Browsing by study line "Husdjursvetenskap"
Now showing items 21-40 of 78
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(2024)With growing consumer interest in the nutritional benefits of high-quality beef, livestock producers face the challenge of enhancing carcass traits, which are typically measurable post-slaughter. As a result, breeding for carcass traits often entails lengthy waiting periods for progeny testing and the need to sacrifice the bull’s progeny for carcass trait assessment. This study aims to estimate the genetic parameters of conformation traits (stature [S], withers width [WW], inner hindquarter [IHQ], hindquarter width [HQW]) and their genetic correlations with carcass traits (carcass weight [CW], carcass conformation [CC], fat class [FC]) using the records of two beef cattle breeds (Charolais: 1,620 and Limousine: 1,326) obtained from the Finnish Animal Breeding Association. A univariate model was used for heritability estimation and a bi-variate model for genetic correlations. The variance and co-variance components were estimated using the restricted maximum likelihood (REML) method in the DMU software. Heritability estimates (±standard error) varied from 0.17±0.04 (FC) to 0.33±0.04 (CC) for Charolais, and from 0.15±0.05 (CW, FC, and WW) to 0.33±0.05 (S) for Limousine. The study found CC to have the highest heritability in both Charolais (0.33±0.04) and Limousine (0.31±0.05) among the carcass traits, indicating a faster response to selection and a higher potential for improvement. Statistically significant correlations were found between conformation and carcass traits, with HQW, IHQ and WW displaying moderate to strong correlations (ranging from 0.32 to 0.79) with CC across both breeds. Additionally, S, HQW and WW exhibited genetic correlations with CW. These results suggest the potential of utilizing these conformation traits as early indicators for the respective carcass traits. These findings offer insights into the potential of using conformation traits as early indicators for selecting animals with desirable carcass traits, thereby guiding breeding decisions towards improved beef quality, as well as promoting resource efficiency.
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Heritabilities of conformation and movement traits from linear assessments of young Icelandic horses (2024)In Finland the evaluation of young Icelandic horses is relatively more common than the evaluation of adults. The goal of this study was to find out about heritabilities and genetic correlations of conformation and movement traits evaluated in young horse linear assessment with horses of age 1-2-year-old. Record data contained the assessment of 354 horses from years 2010-2023. From the assessed traits 18 were selected for calculations. These traits included conformation and movement traits as well as one temperament trait. DMU-program was used to estimate the result using REML-method. Linear model used for all traits contained age, sex, and the assessment event as fixed effects, even though not all of these had statistically significant effect on all traits. Heritability values ranged from 0 to 0,86. For two traits the heritability was zero and only eight traits had a statistically significant heritability value. The genetic correlation was very high between several traits. The average breeding values for eight traits slightly increased over years when observed per birth year. 10 stallions with the most assessed offsprings were selected for further breeding value study. From the breeding values it was possible to observe differences between the stallions. Accuracies of the breeding value estimates were 0,6-0,9 for the traits with higher heritability and 0,3-0,8 for the lower ones, depending on the trait and individual. The results from this study are promising, although it a is bit difficult to compare them to similar previously done studies due to the lack of them and due to the fact that heritability values are tied to the population. It would be good to repeat this study with a bigger dataset to minimize the high standard errors and thus improve the accuracy of the results. The breeding values indicate that information from conformation and movement evaluation from young horses could be used as a tool of selection, but it would be good to first study how the results of young horses are connected to the results from breeding assessment of adult horses.
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(2023)Karkearehuvaltaisessa ruokinnassa yli puolet lehmien syömästä kuiva-aineesta on peräisin karkearehuista. Suomessa nurmisäilörehuun ja viljaan pohjautuvaa ruokintaa on perinteisesti täydennetty rypsi- ja rapsirehuilla, jotta korkeatuottoisten lypsylehmien ravintoaineiden tarve on saatu tyydytettyä. Herneen (Pisum sativum) siemen on yksi kotimainen täydennysvalkuaisrehuvaihtoehto rypsirouheelle ja -puristeelle. Herneen siemenen valkuaisarvo on huonompi kuin rypsipuristeen tai -rouheen, koska herneen siemenen raakavalkuaispitoisuus on pienempi ja valkuaisen pötsihajoavuus suurempi kuin rypsirouheella tai -puristeella. Tämän tutkielman tarkoituksena oli selvittää, miten rypsipuristeen korvaaminen herneen siemenellä lypsylehmien karkearehuvaltaisessa ruokinnassa vaikuttaa lehmien kuiva-aineen syöntiin, maitotuotokseen ja maidon koostumukseen. Koe tehtiin Helsingin yliopiston Viikin tutkimustilalla 31.3.-25.6.2020 syklisenä jaksokokeena, jossa oli kaksi kuuden ayrshirelehmän blokkia ja kuusi koeruokintaa. Lehmät olivat useamman kerran poikineita ja viimeisimmästä poikimisesta oli kulunut kokeen alkaessa keskimäärin 133 päivää. Koejaksoja oli kolme ja jokainen koejakso kesti 17 päivää, joista päivät 14–17 muodostivat näytteiden keruujakson. Koeruokinnat olivat rypsipuriste tai jauhettu herneen siemen ilman merilevää tai merilevillä A. nodosum tai L. digitata täydennettynä. Koeruokinnasta riippuen rypsipuriste (72 g/kg seosrehun ka) tai herneen siemen (109 g/kg seosrehun ka) annettiin isonitrogeenisenä valkuaistäydennyksenä osana seosrehua. Seosrehussa oli lisäksi 2. sadon nurmi-säilörehua (D-arvo 661 g/kg ka) ja ohraa. Merilevät annettiin erikseen yhdessä kivennäisten ja melassileikkeen kanssa. Koeruokintojen karkearehu-väkirehu-suhde oli 65:35 kuiva-aineessa. Koejaksojen välissä oli 18-päiväinen washout-jakso, jolloin lehmät eivät saaneet merilevää. Koeruokintojen välillä ei havaittu eroa kuiva-aineen syönnissä (22,8 kg ka/pv), mutta rypsipuristeen korvaaminen herneen siemenellä paransi tärkkelyksen saantia sekä vähensi raakavalkuaisen, ohutsuolesta imeytyvän valkuaisen ja kokonaisrasvan saantia tilastollisesti merkittävästi. Lisäksi rypsivalkuaisen korvaaminen hernevalkuaisella vähensi suuntaa-antavasti muuntokelpoisen energian saantia. Laskennallinen pötsin valkuaistase oli kaikilla koeruokinnoilla positiivinen (yli 650 g/pv), mutta herneen siementä saaneiden lehmien pötsin valkuaistase oli tilastollisesti merkittävästi pienempi kuin rypsipuristetta saaneiden lehmien. Herneen siemen paransi suuntaa-antavasti raakavalkuaisen näennäistä kokonaissulavuutta rypsipuristeeseen verrattuna. Myös kuiva-aineen kokonaissulavuus parani, kun rypsipuriste korvattiin herneen siemenellä. Sen sijaan tärkkelyksen ja kokonaisrasvan näennäiset kokonaissulavuudet huononivat herneen siemenen korvatessa rypsipuristetta. Herneen siemen vähensi maitotuotosta tilastollisesti merkittävästi (1,5 kg/pv) sekä rasvatuotosta suuntaa-antavasti rypsipuristeeseen verrattuna. Sen sijaan valkuaistuotokseen koeruokinnalla ei ollut vaikutusta, vaikka maidon valkuaispitoisuus oli herneruokinnoilla tilastollisesti merkittävästi suurempi kuin rypsiruokinnoilla. Maidon rasva- ja laktoosipitoisuuksissa ei koeruokintojen välillä havaittu eroa. Energiakorjattua maitotuotosta tarkasteltaessa erot rypsi- ja herneryhmien välillä tasoittuivat hieman, mutta erot olivat edelleen tilastollisesti merkittäviä (31,2 vs. 30,3 kg/pv, vastaavasti). Vaikka tässä tutkimuksessa herneen siementä saaneiden lehmien maitotuotos oli selvästi pienempi kuin rypsipuristetta saaneiden lehmien, eivät tuotoserot ole selitettävissä ainoastaan täydennysvalkuaisen lähteen vaihdolla. Tutkimuksessa käytetty säilörehu oli sulavuudeltaan heikohkoa, mikä on todennäköisesti vaikuttanut negatiivisesti pötsimikrobien energian saantiin ja sitä kautta mikrobivalkuaisen synteesin tehokkuuteen.
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Inverkan av mjölkproduktion, foderdiet och ensilage på förekomst av våmacidos och ketos hos mjölkkor (2024)Subacute ruminal acidosis (SARA) and ketosis are metabolic diseases that occur in milking cows and affect milk production and feed efficiency. The aim of this thesis was to investigate how milk production and composition of diet and silage affected the occurrence of ruminal acidosis and ketosis in milking cows. Data was provided from six dairy farms with milking robots. From the farms, data was collected from milking test-day results, rumination and performance reports from robot. The farms took samples from silage regularly and feeding plans were updated continuously. Three farms with Gea and three farms with Lely milking robots participated in the study. Data from these farms were collected and sorted in separate Excel-files and analysed with logistic regression analysis to obtain the odds ratios for ruminal acidosis and ketosis and to compare the farms with each other. The odds ratio for ruminal acidosis increased with increasing milk production and concentrate allowance for both Lely- and Gea farms. When dietary and silage crude protein concentration increased the odds ratio for ruminal acidosis decreased in Gea farms but not in Lely farms. An increase in dietary concentrate proportion increased and increase of dietary fibre decreased the odds ratio for acidosis in both farm groups, while an increase of dietary starch and silage fibre increased the odds ratio only in Gea farms. The odds ratio for ketosis decreased when milk production increased in Lely farms. The odds ratio for ketosis increased in Gea farms but decreased in Lely farms when concentrate allowance increased. An increase of dietary starch decreased the odds ratio for Gea-farms but not for Lely-farms. The odds ratio for ketosis decreased for both groups when rumination time increased. There were differences in the odds ratio for ruminal acidosis and ketosis between the farm groups for milk production, rumination time and for various descriptive variables regarding the composition of feeding diet and silage. This suggests that in addition to production level and feeding composition there are other factors influencing the risk of ruminal acidosis and ketosis in farms.
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(2022)The aim of the study was to find out how the thickening of fish oil affects the total digestibility of fat in dog food. The study used solid fat paste compared to liquid salmon oil. Both fat preparations were studied as a supplement to complete dog food. The research hypothesis is that the thickening treatment of oil for dogs does not affect its digestibility. The study was carried out in collaboration with the University of Helsinki and Olini Oy, and the test fats were produced in Olini Oy's own experimental kitchen. The experimental group of the study was 12 volunteer dogs, which were fed with pre-calculated and weighed experimental feed. The dogs lived with their owners at home and were fed experimental feed twice daily. The total duration of the experiment was three weeks. The acclimatization period of the experimental feed lasted for 7 days, after which the dogs were given a paste-like fat supplement. During the first 5-day collection period, faecal samples were collected in plastic bags from the experimental dogs. There was a two-day break between treatments when no faecal samples were collected. In the second collection period, the dogs were fed an oil supplement, and the feces were collected for 5 days. Every dog was performed with both treatments. Dry matter, ash, organic matter, crude protein, crude fat, gross energy and AIA tracer were analyzed from the feed and faecal samples used in the experiment. The apparent digestibility of the fat paste diet was numerically lower for all the nutrients than that of the oil diet. There was a statistically significant difference in the apparent digestibility of crude protein and crude fat. Although the difference was statistically significant, it was not very biologically significant in practice. In practice, the total digestibility of fat paste is almost as good in dog digestion as that of liquid oil. Artificial thickening alters the molecular structure of the oil, which can have effects on the absorption of fatty acids into the bloodstream. A product completely similar to that used in this study, has not previously been prepared for animal feed, so further research would be needed.
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(2021)Maissinviljelyn yleistymiseen 2000-luvun aikana Suomessa ovat vaikuttaneet uudet lajikkeet, joilla on nopeampi kehitysrytmi ja parempi kylmänsietokyky. Ilmaston lämmetessä viljelyn odotetaan kasvavan entisestään. Nautakarjan rehuksi viljeltäessä rehumaissin etuna verrattuna nurmisäilörehuun on kertakorjuulla saatava suuri kuiva-ainesato ja suuri energiapitoisuus. Tässä maisterintutkielmassa selvitettiin korjuuajankohdan ja lajikkeen vaikutusta rehumaissin sokeri- ja tärkkelyspitoisuuteen sekä in vitro -sulavuuteen. Aineisto kerättiin Helsingin yliopiston Viikin tutkimustilalla kasvukauden 2019 aikana tehdystä kenttäkokeesta. Osaruutukokeessa pääruututekijänä oli korjuuajankohta (101, 123 ja 144 vrk) ja osaruututekijänä lajike (P7326, P7034, MAS 10.A, MAS 08.F). Lisäksi tutkittiin lämpösumman vaikutusta sulamattoman neutraalidetergenttikuidun (iNDF) pitoisuuteen käyttäen aineistona Viikissä kolmena peräkkäisenä kasvukautena (2017-2019) tehtyjen ruutukokeiden tuloksia. Maissirehun sokeripitoisuus pieneni ja tärkkelyspitoisuus suureni myöhempinä korjuuajankohtina. Ravintoarvo oli suurin korjattaessa rehu 144 vrk kylvöstä. Rehun sulavuus oli suurimmillaan 123 vrk kylvöstä, mutta sulavuus ei laskenut tilastollisesti merkitsevästi korjattaessa rehu 144 vrk kylvöstä. Lajikkeista MAS 08.F sisälsi eniten sokeria ja vähiten tärkkelystä, joten sen ruokinnallinen laatu oli heikoin. MAS 10.A:n sokerin ja tärkkelyksen yhteispitoisuus oli suurin ja sulavuus muita lajikkeita parempi. Lajikkeiden koostumuksen muutokset eivät vastanneet aiempien tutkimusten tuloksia, joissa aikaisemmat lajikkeet sisälsivät enemmän tärkkelystä kuin myöhäisemmät lajikkeet. Lämpösumman kasvaessa rehun iNDF-pitoisuus lisääntyi. Kun lämpösumman kertymä laskettiin käyttämällä rajana +10 °C keskilämpötilaa iNDF-pitoisuus kuiva-aineessa kasvoi astetta kohden kaksi kertaa enemmän kuin laskettaessa lämpösumman kertymä käyttämällä rajana +5 °C keskilämpötilaa. Etelä-Suomen olosuhteissa on siis mahdollista korjata laadukas rehumaissisato nautakarjalle. Riittävän pitkä kasvuaika mahdollistaa tärkkelyksen kertymisen tähkään, mikä kompensoi kasvin ikääntyessä tapahtuvaa kuidun sulavuuden heikentymistä.
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(2024)The background of the research was a societal need to find a compensatory for peat, which is widely used as a horses’ bedding material in Finland. It is estimated that exploitation possibilities and availability of peat is decreasing in the future. Because of the horses' welfare, it is needed to be researched what kind of bedding material would be as agreeable material for horses as peat is. In this research, the effects of two different bedding materials, reed canary grass pellets and peat, on horses' resting and sleeping behavior were investigated. The research was a part of the UNIHEPO-project, and it was executed in Ylä-Savo Vocational College, in Hingunniemi unit, at Kiuruvesi in November-December in 2022. The study consisted of two 21-day experimental periods. In the first period individual pens were littered by reed canary grass pellets of 15 centimeters. In the second period individual pens were littered by 15 centimeters of peat. Altogether 16 clinically healthy riding horses were involved, and they were kept in the same individual stalls. Horses’ behavior was recorded by videocameras, and their rest and sleep behavior were observed from both periods’ two (2) first and last days between 4 pm and 6 am. The average total duration of horses’ rest and sleep behavior were determined by dividing horses’ total duration of behavior by the number of behavioral periods. The differences between bedding materials were tested by linear repeated measurement to mixed models. The results of the research gave more information about horses’ rest and sleep behavior and how reed canary grass pellets affect horses' rest and sleep behavior compared to peat litter. The results showed that horses' rest behavior was longer on peat. Reed canary grass pellets increased horses’ activity of the neck and decreased the length of laying down periods during the first days of the period. On peat horses’ total duration of sleep was found to be longer and the rest that appeared to be paradoxical sleep was also longer. The horses laid on lateral and sternal recumbency more often and longer on peat periods. Results show that in the future more research is needed to be done into other bedding materials and their effects on horses’ rest and sleep behavior to promote horses’ wellbeing.
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(2024)Grazing is a species-typical behavior for cows. In Finland, some dairy farms graze their cows, but grazing is decreasing as herd sizes increase. However, consumers demand more welfare to dairy cows, and many Dairies have started paying an additional price for milk if farms graze their cows. The research was carried out as part of the GRAZE-WEL project, in which the University of Helsinki and the Natural Resources Institute Finland are involved. The study viewed at the welfare of dairy cows on 15 Finnish practical dairy farms, of which 8 were freestalls and 7 were tiestalls. Of the farms in the study, all tiestalls grazed their cows in accordance with the law, and 4 freestalls grazed. A welfare assessment visit was carried out to the farms twice during the study, before and after the possible grazing season, so that the effects of grazing could be compared. During the welfare assessment visit, cow`s body condition class, cleanliness, knee and hock lesions and degree of lameness were classified. Average results were calculated and analyzed using the SAS statistical program`s generalized linear mixed model. The housing types studied were tiestall with grazing, freestall with grazing and freestall without grazing. The body condition of cows of all housing types decreased during the summer. The effect of classification time on body condition was statistically significant. Cows in both housing types with grazing were cleaner at the end of the grazing season than before the grazing season. The cleanliness of the cows was significantly affected by the time of classification. Knee and hock lesions decreased during the grazing season only in tiestall cows. The common factor of housing type and classification time had a significant effect on the classification results of knee and hock lesions of tiestall cows and non-grazed freestall cows. The lameness of cows decreased during the summer only in cows with tiestall housing. Tiestall cows benefited the most from grazing, as their welfare results improved in all areas during the summer. The welfare results of grazed freestall cows during the indoor feeding season were better than those of other housing types and remained the most consistent throughout the study.
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(2020)Linear scoring of livestock and farm animals has been in use since the 1980’s. In Europe, the first linear evaluations in horse breeding were conducted in 1989. In Finland, the linear evaluation was introduced into breeding evaluation of warmblood horses in 2015. So far, there is only a limited amount of research available about the heritabilities calculated from linear evaluation. Some of the studies have shown that the judge has a statistically significant effect on the linear conformation evaluation of the horse. The heritabilites from these studies have varied within different researches. The highest siginificant heritabilities have been found for conformation traits. For now, only warmblood horses are being evaluated linearly in Finland. The aim of this study was to estimate the heritabilities of the leg and movement traits from show data between 2015 – 2019 and to estimate the genetic correlations between different traits. All in all 26 traits were analyzed in the study. There were 915 horses in the data. Observations were gathered from 29 different shows in Finland. Both geldings, mares and stallions were represented in the data, mares being the largest group of gender. From one singular age group, the two – year- old mares had the greatest amount of observations. Based on the year of birth, horses born in 2015 had the most observations. The year of birth did not, however, have any significance on the results. Both the age and the gender of the horse did have a statistic significance on the results. Also the location of the show and the year of observation had some significance. Heritibilities of leg traits based on this data were extremely low, ranging between 0,00 – 0,11. The heritabilities of type and movement traits ranged between 0,00 and 0,28. Standard errors of heritabilities ranged between 0,09 – 0,14. Genetic correlations between the traits ranged between weak to strong. Standard errors of genetic correlations ranged between 0,04 – 0,13. To get reliable heritability parameters, more data and research is needed about the linear scoring of horses.
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(2020)Residual feed intake (RFI) is a measurement method used in animals to determine feed efficiency. Improving feed efficiency has been found to be more cost-effective than maximizing daily gain. Determining the feed efficiency is laborious as the measurement periods are long and expensive. The problem is the limited capacity of the measuring devices in relation to the number of animals, because the animals daily dry matter intake (DMI), average daily gain (ADG) and metabolic body weight (MMBW) must be measured over a sufficiently long continuous period. The aim of the study was to optimize the measurement of residual feed intake to reduce workload. In this case, the costs of measurement would be lower, and the utilization rate of measuring equipment would be improved. The study sought a critical limit on the amount of data required. Measurements were removed from the data until it was found that the reliability of the results was affected. The hypothesis was that the fewer measurements and the shorter the measurement period, the greater the risk of error in the results. The study material included 105 dairy bulls and the experiment lasted 56 days. DMI was measured for each animal and the animals were weighed once a week during the experiment, a total of nine times (double weighings at the beginning, middle and end of the measurement period). The growth curves were used to calculate the ADG and MMBW of the animals. In addition, the area of the area of the cross-section of the longissimus muscle (M.longissimus dorsi) and the thickness of the back fat of each bull were measured with an ultrasound device at the end of the experiment. RFI was calculated for seven different measurement periods. The original 56-day period was shortened to seven days at a time until the period was 28 days. Ultrasound measurements were added to the 56-day measurement period model only. In addition, the number of weighing was reduced from nine to five and three times from the original 56-day model. The addition of ultrasound measurements weakened the statistical model compared to the initial 56-day measurement period. The animal RFI results changed the most in the 28-day and 35-day models. The reliability of the results decreased the least in the 49-day and five-weighing models. The ADG and MMBW averages remained almost the same in the models until 35 days. The shorter the measurement period, the more the DMI values changed. Based on the results, shortening length of the RFI measurement period to 42 days had no market effect on the results. A 42-day measurement period is enough for DMI, but a longer measurement period is recommended for ADG. Three weighings did not change the ADG as much as the 49-day measurement period and was more reliable than the 42-day measurement period. Adding longissimus muscle and back fat to the RFI model did not improve the reliability of the model and thus did not provide added value. Based on this study, ultrasonic measurements are not required to determine RFI, and the workload can also be reduced by shortening the measurement period or reducing weighing times.
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(2024)Linear classification is used in cattle breeding to estimate animal’s production traits. Classification can be done early for a young animal. Muscularity scores in classification are used to estimate the animal’s slaughter traits. During slaughter, carcasses are scored based on muscularity, fatness and weight. The price of the carcass is based on these scores, so it is important for the farm’s profitability to improve slaughter traits. If conformation scores are used to make breeding decisions to improve slaughter traits, those classification scores need to correlate with the slaughter scores both phenotypically and genetically. Phenotypic scores are important especially when choosing animals for breeding because breeding values are not calculated for conformation traits in Finland. The aim of this study was to estimate phenotypic and genetic correlations between Finnish linear classification scores and slaughter scores in beef cattle. Phenotypic correlations were estimated for Angus, Hereford, Charolais, Limousin and Simmental. Genetic correlations were estimated for Hereford and Charolais. Phenotypically the strongest correlation in every breed was between inner thigh width and slaughter traits (-0.20-0.71). Weakest phenotypic correlation in every breed was between thigh length and slaughter traits (0.01-0.21). Genotypic correlations were similar compared to phenotypic correlations in Hereford and Charolais breeds. In both breeds the correlation between hip height and carcass conformation was negative (-0.11 and -0.20), but the genetic correlations between inner thigh width and muscularity score and carcass information were strong positive (0.48-0.81). Phenotypic correlations estimated simultaneously with genetic correlations were also similar but significantly weaker compared to straight phenotypic estimations. That’s possibly because the data used in straight phenotypic estimations was more narrowed compared to the data used in genetic estimations. Heritabilities were estimated for the traits used in genetic correlation estimations. Those estimated heritabilities were moderate (0.18-0.39) in both Hereford and Charolais breeds which is similar result to earlier studies. Based on this research, linear classification muscularity scores can be used as a reliable indicator trait when choosing animals for breeding to improve slaughter traits, especially carcass conformation.
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(2023)Terve ja tuottava lypsylehmä on eettisesti, ekologisesti ja ekonomisesti kestävän maidontuotannon perusta. Suurin tuotantosairauksien riski ajoittuu poikimisen läheisyyteen, jolloin lehmä läpikäy suuria fysiologisia muutoksia ravintoaineiden ohjautuessa alkavaan maidontuotantoon. Lypsylehmän lihavuudella on havaittu olevan yhteys alkulypsykauden pidentyneeseen, voimakkaasti negatiiviseen energiataseeseen, mikä altistaa eläimen hedelmällisyysongelmille ja tuotantosairauksille. Hypoteesina oli, että edellisen lypsykauden lopussa enemmän lihovilla lehmillä on pienempi märehtimisaika laktaation alussa, pienempi 305 päivän maitotuotos, suuremmat plasman BHBA- ja NEFA-pitoisuudet sekä pienempi valkuais- ja suurempi rasvapitoisuus maidossa. Aineisto oli kerätty Viikin tutkimustilalla 1.1.2017–6.10.2021. Data koottiin Minun Maatilani -ohjelmistosta, lypsyrobotin tallentamasta aineistosta, aiempien tutkimusten aineistoista, tuotosseurannan tiedoista ja aktiivisuussensorien tallentamasta aineistosta. Lehmien elopainon muutosta tarkasteltiin kahden peräkkäisen laktaation aikaväleiltä 7–49, 7–91, 49–287 ja 91–287 päivää poikimisesta. Elopainonmuutoksia saatiin yhteensä 127 lypsylehmältä ja 344 laktaatiosta. Tutkimuksessa havaittiin heikko yhteys laktaation lopun lihomisen ja seuraavan alkulaktaation laihtumisen välillä useamman kerran poikineilla lehmillä. Loppulypsykauden lihominen pienensi seuraavan laktaation maitotuotosta ja maidon valkuaispitoisuutta. Edellisen laktaation painonmuutoksilla ei havaittu olevan yhteyttä maidon rasvapitoisuuteen, alkulaktaation märehtimiseen sekä plasman NEFA- ja BHBA-pitoisuuksiin. Alkulaktaation suurempi laihtuminen nosti maitotuotosta, maidon rasvapitoisuutta sekä veren NEFA- ja BHBA-pitoisuuksia. Kahden peräkkäisen laktaation loppuvaiheen elopainon muutokset korreloivat positiivisesti keskenään. Loppulypsykauden lihominen ei ollut yhteydessä suurempaan rasvakudosten käyttöön seuraavan laktaation alussa. Pelkkä elopainon muutoksen suuruus voi kuitenkin olla riittämätön lihomisen mittari. Systemaattista kuntoluokitusta eri tuotoskauden vaiheissa tarvitaan, jotta voidaan arvioida lypsylehmän lihomista ja laihtumista.
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(2022)Lypsylehmillä siirtymä- eli transitiokausi on ajanjakso, joka alkaa kolme viikkoa ennen poikimista ja jatkuu poikimista seuraavat kolme viikkoa. Tuona aikana lehmässä tapahtuu suuria aineenvaihdunnallisia muutoksia, ja jopa 75 % kaikista terveydellisistä ongelmista ilmenee tällä ajanjaksolla. Lihavat lehmät mobilisoivat poikimisen jälkeen kudosvarojaan runsaasti, jolloin ne vähentävät syöntiään ja kärsivät helpommin negatiivisesta energiataseesta normaalikuntoisiin lehmiin verrattuna. Syönnin vähentyessä myös märehtiminen vähenee. Lihavuus lisää riskiä aineenvaihdunnallisille ja tulehduksellisille sairauksille, sillä lihavuus lisää rasvakudoksen tulehdusta välittävien sytokiinien tuotantoa ja heikentää maksan toimintaa. Tämän tutkimuksen tavoitteena oli selvittää edellisen ja meneillään olevan lypsykauden eri aikaväleillä tapahtuneita lehmien elopainon muutoksia ja niiden yhteyttä lehmien aineenvaihdunta- ja hedelmällisyysongelmiin, utareterveyteen ja jalkaterveyteen. Lisäksi tutkittiin lihavuuden yhteyttä märehtimisaikaan. Tutkimuksessa hyödynnettiin Helsingin yliopiston Viikin tutkimustilalla 1.1.2017 – 6.10.2021 kerättyä tietoa. Lehmien poikimapäivät, poistot ja muut tarvittavat eläintiedot saatiin Minun Maatilani -ohjelmistosta, märehtimistiedot (min/pv) lypsyrobotin järjestelmästä, maitonäyteanalyysit Valion Valma-palvelusta ja terveystiedot Nautaeläinten terveydenhuoltojärjestelmä Nasevasta sekä navettapäiväkirjoista. Tutkimusaineistoon sisällytettiin kyseisenä ajanjaksona vähintään kaksi kautta lypsäneet lehmät, jotta oli mahdollista analysoida loppulypsykaudella tapahtuvan lihomisen yhteyttä seuraavan lypsykauden alun terveyteen. Yhteensä tutkimuksessa oli mukana 166 ayrshire-lehmää. Pihatossa olleet lehmät punnittiin jokaisen lypsykerran alussa lypsyrobotin vaa’alla. Elopainon muutokset laskettiin seuraavilta aikaväleiltä: 7–49, 7–91, 49–287, 49–217, 91–287, 91–217, 7–287 ja 7–217 päivää poikimisesta. Lehmien paino pieneni alkulaktaation aikana ja suureni keskilaktaatiosta loppulaktaatioon. Edellisellä lypsykaudella keskimääräistä enemmän lihoneet lehmät märehtivät seuraavalla lypsykaudella vähemmän. Edellisellä lypsykaudella tapahtunut lihominen ei lisännyt seuraavan lypsykauden terveysongelmia, vaan keskimääräistä suurempi lihominen oli yhteydessä jopa vähäisempiin terveysongelmiin. Lehmät, jotka laihtuivat alkulypsykaudesta, kärsivät saman lypsykauden aikana aineenvaihdunnallisista häiriöistä ja heikommasta utareterveydestä. Lypsykauden loppupuolella enemmän lihoneilla lehmillä oli puolestaan saman lypsykauden aikana vähemmän terveysongelmia. Näin ollen edellisellä loppulypsykaudella tapahtuvaa kohtuutonta lihomista ja siitä aiheutuvaa alkulypsykauden laihtumista tulisi välttää, mutta kohtuullinen lihominen ei lisää terveysongelmia, vaan saattaa jopa olla seurausta paremmasta terveydentilasta.
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(2024)During the lactation cycle of dairy cows, the feeding strategy can influence the milk yield and the animal's welfare. During early lactation in particular, major changes occur in the metabolism of cows. The cow's body condition score at calving affects early lactation period, as fatter cows mobilize their tissue reserves abundantly due to lower dry matter intake and thus more severe negative energy balance. Excessive mobilization of fat tissue stores can manifest as a metabolic disorder called ketosis. The well-being of the cow and successful feeding has a positive effect on the milk yield and thus also on the economic profitability of the farm. The aim of this study was to examine how concentrate feeding of dairy cows should be implemented throughout the lactation, when lower than usual proportion of concentrate is fed (about 35% of diet dry matter). In the feeding trial, the effects of the concentrate feeding schemes on milk yield of cows during the early and late lactation were investigated. The study also investigated the effects of the concentrate feeding model on the cow's energy balance and the change in live weight and body condition score. The study compared feeding a flat rate of concentrate throughout the lactation to distributing concentrate unevenly according to the lactation stage. The research was carried out in the experimental dairy barn of the Natural Resources Institute in Finland in Jokioinen as two different sub-experiments, where cows in the early and late lactation formed their own experimental groups. Both groups consisted of 20 Nordic Red dairy cows. Early lactation cows started the experiment immediately after calving, unlike cows in the late lactation, which started their experiment all at the same time (approx. 213 days after calving). All cows were fed a total mixed ratio with a concentrate content of 25% in dry matter, the concentrate proportion in the whole diet was adjusted in concentrate stations. The experimental groups were randomly divided into two different groups. The concentrate proportion in early lactation cows was 35% or 45% of the total dry matter intake, and 35% or 27% for late lactation cows. Cows in the early lactation were given 2 dl of propylene glycol per day. Timothy-meadow fescue silage from 1st cut with a D-value of 697 g/kg dry matter was used as forage in the diet. The feeding trials lasted eight weeks. During the trials, the milk yield, feed consumption and live weight of the cows were measured daily. The body condition score of all animals were determined at the beginning and end of the experiment. In addition, blood samples were taken from the cows in the early lactation at production weeks 1, 3 and 6 to determine plasma beta-hydroxybutyrate (BHB) and non-esterified fatty acids (NEFA) concentrations. Based on the current study, it was concluded that in a grass silage-based feeding model, it is the best to emphasize the feeding of concentrate at the beginning of lactation and give less concentrate in late lactation. However, there were no health benefits from a higher proportion of concentrate in terms of energy balance at early lactation when compared to a lower rate of concentrate. Emphasis on concentrate distribution at early lactation is more profitable feeding strategy compared to flat concentrate rate due to increased milk yield and financial results. In addition, the lower live weight gain achieved in the end-lactation with lowered concentrate feeding rate has advantages for the cows' next calving and the beginning of the subsequent production period.
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(2021)It is necessary actively seek effective ways to reduce agricultural emissions so that the proportion of agricultural greenhouse gas emissions in total national emissions does not increase. The aim of this study was to evaluate with carbon footprint calculators different options for reducing greenhouse gas emissions of dairy production and the carbon footprint of energy-corrected milk. The scenarios included the changes in the dietary concentrate proportion, the proportion of grass in cultivation, the digestibility of roughage and the level of milk production. In addition, the effect of temperature on methane emissions from manure was examined. Data of a dairy farm located in Central Ostrobothnia from year 2020 were utilized in the study. The assessment was carried out by using the carbon footprint calculator developed by the European Commission and the Valio Carbo® environmental calculator. According to the results of both calculators, the effect of the changes in the concentrate proportion in the diet on the carbon footprint of milk was very small. Reducing the proportion of concentrate in the diet reduced total emissions. Reducing the proportion of rapeseed meal in feeding reduced total emissions more than reducing the proportion of barley. Increasing the proportion of grass in cultivation reduced the carbon footprint of milk and the total amount of greenhouse gas emissions with both calculators. According to the European Commission carbon calculator, increasing grass yield and also increasing the proportion of grain in cultivation reduced the carbon footprint of milk and the total amount of greenhouse gas emissions. With Valio Carbo® environmental calculator, increasing the proportion of grain in cultivation increased the carbon footprint of milk and the total emissions. According to European Commission calculator, the total emissions and the carbon footprint of milk decreased when the digestibility of roughage decreased. The increase of milk production level also clearly reduced the carbon footprint of milk with both calculators. However, the change in the milk production level had only a small effect on the amount of emissions produced. Reducing the conversion factor describing the effect of temperature on methane formation from slurry reduced the carbon footprint of milk. The decrease in the conversion factor reduced the emissions from the manure system by 51.3 percentage and reduced the milk carbon footprint from 1.21 to 1.15 kg CO2e/kg ECM. In conclusion, there are many feasible opportunities to reduce the carbon footprint. The most effective ways to reduce total emissions at farm level are to increase the proportion of grass in cultivation and to increase the yield of grass. Raising the milk production level effectively reduces the carbon footprint, but in the future the calculations must take into account that the dry matter intake is higher as the milk yield increases. The main differences between the calculators are currently in the coefficients they use. When comparing the results given by the calculators, it is important to note that the calculation principles cannot fully take into account the possible opposite effects of different factors. The results should be looked critically with a caution that the results given by different calculators are not directly comparable.
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(2022)Uusien lajikkeiden myötä maissin rehuviljely on tullut ajankohtaiseksi myös pohjoisemmilla alueilla Euroopassa. Maissisäilörehun pienen raakavalkuaispitoisuuden takia ruokinnassa käytettävän valkuaisrehun tulee mahdollistaa riittävä valkuaisen ja aminohappojen saanti ruokinnasta. Rypsin ja härkäpavun viljely on mahdollista Suomen olosuhteissa, ja ne voisivat soveltua hyvin valkuaistäydennykseksi maissisäilörehua sisältävään ruokintaan. Tutkimuksen tavoitteena oli selvittää maissisäilörehun ja kahden eri valkuaistäydennyksen vaikutusta lypsylehmien syöntiin, dieetin sulavuuteen, maitotuotokseen ja aineenvaihduntaan, kun nurmisäilörehun kuiva-aineesta 50 % korvattiin maissisäilörehulla. Ruokintakoe toteutettiin cyclic change over -koemallin mukaisesti kolmessa 21 vuorokauden jaksossa. Kokeessa oli kuusi erilaista ruokintaa ja kaksi tuotosvaiheen perusteella muodostettua kuuden eläimen blokkia. Kokeessa oli mukana 12 useamman kerran poikinutta ayrshire -rotuista lypsylehmää. Koeruokinnat muodostettiin 2 x 3 faktoriaalisesti kahdesta karkearehusta (1. sadon nurmisäilörehu vs. nurmi- ja maissisäilörehun seos (50:50)) sekä kolmesta valkuaiskoostumukseltaan erilaisesta väkirehuseoksesta. Väkirehuseoksista yksi sisälsi niukasti rypsirouheen ja härkäpavun valkuaista ja kaksi runsaammin valkuaista siten, että lisävalkuaisen lähteenä oli joko rypsirouhe tai härkäpapu. Valkuaisrehujen lisäksi seosrehujen väkirehuseos sisälsi ohraa, kauraa, melassileikettä, propyleeniglykolia ja kivennäistä. Seosrehujen karkearehu-väkirehu -suhde oli 58:42 kuiva-aineessa. Ruokinnat eivät vaikuttaneet kuiva-aineen ja orgaanisen aineen syöntiin. Maissisäilörehun lisääminen ruokintaan lisäsi tärkkelyksen ja vähensi raakavalkuaisen ja neutraalidetergenttikuidun saantia sekä heikensi dieetin sulavuutta. Valkuaislisä lisäsi maissisäilörehua saaneiden lehmien maitotuotosta ja energiakorjattua maitotuotosta, mutta ei nurmisäilörehua saaneiden. Valkuaistuotos lisääntyi, kun maissisäilörehua sisältävään ruokintaan yhdistettiin runsaampi valkuaisruokinta, kun taas nurmisäilörehua sisältävällä ruokinnalla vastaavaa ei havaittu. Härkäpapu lisävalkuaisena lisäsi maissisäilörehua saaneiden lehmien valkuaistuotosta, mutta ei nurmisäilörehua saaneiden. Lisävalkuainen lisäsi maidon valkuaispitoisuutta maissisäilörehua sisältävällä ruokinnalla. Ruokinnalla ei ollut vaikutusta maidon rasva- ja laktoosipitoisuuteen. Maidon ureapitoisuus väheni, kun lehmät saivat ruokinnassaan maissisäilörehua. Sen sijaan runsas valkuaisruokinta lisäsi maidon ureapitoisuutta niukkaan valkuaisruokintaan verrattuna. Maidon ureapitoisuus oli suurempi härkäpapua kuin rypsiä sisältävällä ruokinnalla. Valkuaislisä lisäsi maissisäilörehua saaneiden lehmien välttämättömien ja haaraketjuisten aminohappojen yhteenlaskettuja pitoisuuksia, mutta vähensi niitä nurmisäilörehua saaneiden lehmien plasmassa. Plasman aineenvaihduntatuotteiden pitoisuuksissa ei ollut suuria eroja ruokintojen välillä. Valkuaislisä lisäsi hieman plasman glukoosipitoisuutta ja vähensi NEFA-pitoisuutta. Nurmisäilörehun osittainen korvaaminen maissisäilörehulla muuttaa lehmien ravintoaineiden saantia. Maissisäilörehun lisäämisen vaikutus maitotuotokseen tai maidon komponenttien tuotokseen riippuu valkuaisruokinnan tasosta siten, että riittävän valkuaistäydennyksen myötä maissisäilörehua sisältävällä ruokinnalla saavutetaan sama maitotuotostaso nurmisäilörehuun verrattuna. Tutkimuksen tulosten perusteella rypsi ja härkäpapu sopivat hyvin valkuaislisäksi maissisäilörehua sisältävään ruokintaan.
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(2021)Maissi on yksivuotinen heinäkasvi, jonka viljely Suomessa on lisääntynyt merkittävästi ja viljelyala on ollut viime vuosina yli tuhat hehtaaria. Suomessa viljeltävä maissi korjataan tuleentumattomana nautakarjan karkearehuksi. Maissisäilörehu sisältää paljon tärkkelystä ja on siksi erittäin energiapitoinen karkearehu. Maissin viljelyvarmuuden lisääntyessä se saattaisi olla hyvä karkearehuvaihtoehto nurmen rinnalle riskien hajauttamista ajatellen. Maissin etuna viljelykasvina on sen tehokas vedenkäyttökyky sekä yhdellä korjuukerralla saatava suuri sato. Tutkimuksen tavoitteena oli selvittää maissisäilörehun vaikutuksia lypsylehmien maidontuotantoon, dieetin sulavuuteen ja typen hyväksikäyttöön, kun nurmisäilörehua korvataan osittain maissisäilörehulla. Tutkimus toteutettiin kolmena 3 x 3 latinalaisena neliönä, joissa oli mukana 9 ayrshire-rotuista lehmää. Lehmät olivat parsissa ja ne lypsettiin kaksi kertaa päivässä. Kokeen lehmät olivat poikineet 2 – 4 kertaa ja kokeen alkaessa niiden poikimisesta oli keskimäärin 69 ± 17,4 (SD) päivää. Tutkimuksessa oli kolme erilaista koeruokintaa, joiden karkearehuvaihtoehdot olivat puhdas nurmisäilörehu (kuiva-aine 316 g/kg, D-arvo 652 g/kg ka) sekä seokset, joissa 25 % tai 50 % nurmisäilörehun kuiva-aineesta korvattiin maissisäilörehulla (kuiva-aine 359 g/kg, D-arvo 679 g/kg ka). Karkearehuseoksia täydennettiin väkirehun tilaseoksella (ohra, kaura, härkäpapu, herne, melassileike, kivennäinen, propyleeniglykoli). Seosrehujen karkearehu-väkirehu -suhde oli 65:35 kuiva-aineessa. Lehmille oli tarjolla vapaasti seosrehua ja vettä. Lisäksi lehmät saivat täysrehua 7 kg/pv. Nurmisäilörehun korvaaminen maissisäilörehulla nosti lineaarisesti lehmien kuiva-ainesyöntiä (24,3 vs. 25,3 vs. 26,0 kg ka/pv) ja maitotuotosta (32,8 vs. 33,3 vs. 34,0 kg/pv). Maidon rasvapitoisuus nousi 5,6 %, kun nurmisäilörehun kuiva-aineesta korvattiin 50 % maissisäilörehulla. Valkuaispitoisuuteen maissisäilörehulla ei ollut vaikutusta. Paras energiakorjattu maitotuotos (33,2 kg vs. 33,6 kg vs. 35,3 kg) saavutettiin, kun karkearehun kuiva-aineesta 50 % oli maissisäilörehua. Maissisäilörehun osuuden lisääntyessä ruokinnassa ravintoaineiden sulavuus heikkeni ja typen hyväksikäyttö (N tuotos/ N saanti) parani (0,286 vs. 0,291 vs. 0,306). Tutkimuksen perusteella nurmisäilörehun osittainen korvaaminen maissisäilörehulla nostaa lehmien maitotuotosta ja maidon rasvapitoisuutta. Myös typen hyväksikäyttö paranee maissisäilörehun osuuden noustessa. Tämän tutkimuksen perusteella jopa puolet nurmisäilörehusta kannattaa korvata maissisäilörehulla.
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(2022)Maissi (Zea mays L.) on lämpimiin olosuhteisiin ja lyhyeen päivään tottunut, runsaasti biomassaa tuottava heinäkasvi. Maissia viljellään laajasti ympäri maailman niin rehu- kuin elintarvikekäyttöönkin, mutta Suomessa sitä viljellään lyhyen kasvukauden vuoksi pääasiassa karkearehun tuottamiseksi nautakarjalle. Suomessa maissin viljely säilörehuksi on lisääntynyt pohjoisiin olosuhteisiin soveltuvien lajikkeiden myötä ja viljelypinta-ala on kasvanut viime vuosien aikana jo yli tuhanteen hehtaariin. Suomessa kasvuaika ei riitä maissin jyväsadon korjaamiseen, joten maissikasvusto korjataan tuleentumattomana säilörehuksi myöhään syksyllä. Maissin ruokinnallinen arvo eroaa nurmesta pienemmän raakavalkuaispitoisuuden ja suuremman tärkkelyspitoisuuden vuoksi. Toisin kuin nurmesta, maissista saadaan korjattua yhdellä korjuulla suuri kuiva-ainesato. Maisterintutkielmassani käsittelen maissisäilörehua lypsylehmien ruokinnassa. Tarkoituksena oli selvittää, miten nurmisäilörehun osittainen korvaaminen maissisäilörehulla vaikuttaa lypsylehmien syöntiin, maitotuotokseen ja metaanintuotantoon. Ruokintakoe järjestettiin Helsingin yliopiston Viikin opetus- ja tutkimustilan pihattonavetassa 18.1.-9.4.2020. Tutkimus oli osa Tulevaisuuden kestävät karkearehuvalinnat (Tukeva) -hanketta. Tutkimus koostui kolmesta neljän viikon jaksosta. Jakson viimeinen viikko oli näytteiden keruuviikko. Ensimmäisellä ja kolmannella ruokintajaksolla karkearehusta 50 % oli maissisäilörehua ja 50 % nurmisäilörehua. Toisella ruokintajaksolla karkearehu oli pelkästään nurmisäilörehua. Lehmät saivat koko kokeen ajan väkirehua robotilta keskimäärin 6,2 kg/pv. Seosrehua oli vapaasti tarjolla ja sen karkearehu-väkirehusuhde kuiva-aineessa oli 65:35. Kokeeseen valittiin kymmenen Ayrshire-rotuista lehmää, joiden poikimisesta oli kokeen alkaessa kulunut keskimäärin 98 pv ja maitotuotos oli keskimäärin 46,6 kg/pv. Maissisäilörehun D-arvo oli 679 g/kg ka, kuiva-ainepitoisuus 351 g/kg ja NDF-pitoisuus 390 g/kg ka. Nurmisäilörehun D-arvo oli 652 g/kg ka, kuiva-ainepitoisuus 361 g/kg ja NDF-pitoisuus 590 g/kg ka. Nurmisäilörehun osittainen korvaaminen maissisäilörehulla lisäsi kuiva-aineen syöntiä 0,9 kg/pv ja tärkkelyksen saantia 1,91 kg/pv. Myös muuntokelpoisen energian saanti (MJ/pv) nousi maissisäilörehuruokinnalla 2,7 %. Maissisäilörehu heikensi dieetin sulavuutta. Kuiva-aineen sulavuus väheni 6,2 % ja kuidun sulavuus 32,5 % maissisäilörehun korvatessa nurmisäilörehua. Maissisäilörehuruokinnalla ei ollut vaikutusta maitotuotokseen tai maidon pitoisuuksiin. Metaanintuotanto (g/pv) väheni n. 5 % maissisäilörehuruokinnalla, mutta ruokinnalla ei ollut vaikutusta metaanintuotantoon per tuotettu energiakorjattu maitokilo (EKM). Maissisäilörehun lisääminen ruokintaan pienensi maidon ureapitoisuutta ja paransi typen hyväksikäyttöä. Maissisäilörehu on hyvä karkearehulähde myös Suomen olosuhteissa ja se voi vähentää lypsylehmien metaanipäästöjä (g/pv), mutta tuotekiloa (g/kg EKM) kohti laskettuna päästövähennystä ei välttämättä saavuteta.
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(2023)The importance of equine welfare has become more important in the last years. There is a need for welfare parameters, which help to define and measure the welfare of domestic horses. The importance of sleep on health and wellbeing is well-known in humans but has not yet been extensively studied in horses. It is known that horses sleep either non-REM-sleep or REM-sleep. Also, horses are able to partially sleep in a standing position. For REM-sleep they need to have muscle atony and lie down. Horses are easily disturbed while sleeping and many factors affect how much and how long horses spend sleeping. Horses are also able to postpone their REM-sleep for extensive periods of time, which directly effects their health and welfare. The aim of our study was to measure and analyze how the softness of the bedding in the lying areas affect the sleeping and resting behavior of horses. This thesis was part of the UNIHEPO initiative, which consisted of multiple studies around equine sleep. For our study we conducted a cross over study with sixteen (16) clinically healthy horses in the equine school Ylä-Savon ammattiopisto during fall 2022. The study included three treatments: the normal amount of bedding as the baseline, then thin (5 cm) bedding and thick (15 cm) of bedding. We recorded three periods: the baseline, and then two consecutive periods with half of the stalls having thick bedding and the other half thin. The duration of each treatment period was 21 days, respectively. We switched the treatments after the first period so that that each horse had both treatments. We recorded and analyzed the first two (2) and last two (2) nights of each period. The results were reported as seconds calculated from the median of the daily mean values. Only the data from the two treatments was analyzed for this thesis. The horses exhibited more resting behaviors and supported their necks longer in a sleeping position, when the bedding was thicker (p=0,002). There was no statistically significant difference between the treatments when lateral recumbency bout amounts or lying durations were analyzed, but the lying duration was longer. With thicker bedding the horses had a higher number of sternal recumbency bouts (p=0,013) and the bout duration was longer (p=0,001). Also, the total duration spent in sternal recumbency was higher on thicker bedding (p=0,002). Surprisingly we noticed rolling behavior after lying bouts almost solely on thicker bedding (p=0,004). There were also some tendencies for correlation between the height of the horses, lying bouts and bedding thickness. Our research provided us with valuable information on the factors affecting the sleeping and resting behavior of horses. At the same time the need for further research was highlighted. Still, our results reinforce the scientific knowledge, which is crucial in developing and promoting equine welfare.
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(2021)Iodine deficiency is a global health problem that causes physical and mental development disorders in humans. School-age children, pregnant women and consumers of organic food are particularly vulnerable to iodine deficiency. The popularity of organic products is growing, and attention should be paid to the iodine content of organic milk, as the iodine content of organic milk is usually lower than in conventionally produced milk. The aim of this study was to increase the iodine content of organic milk by adding two different species of seaweed, Ascophyllum nodosum and Laminaria digitata, to dairy cow diets, and thus create a sustainable mineral feeding strategy for dairy cows in organic production. The aim was to study the effect of dietary seaweed addition to iodine content of milk together with rapeseed cake or pea, as rapeseed cake is known to contain goitrogenic compounds that reduce iodine transfer to milk. The experiment was conducted at the Viikki Research Farm from 31 March to 25 June 2020. The experiment included 12 lactating Ayrshire cows and the experimental design was a cyclic changeover study. The factors studied were the effects of dietary protein source (rapeseed cake or pea) and the species A. nodosum or L. digitata on the intake of mineral and trace elements on dairy cows and on the mineral content of milk. In particular, effects on milk iodine were studied. The experiment had three 17-day trial periods and there was an 18-day wash-out period between the periods, when no seaweed was fed in order to minimize the carry-over effects between periods. The samples were collected on the last four days of the periods. Experiment included six dietary treatments in which protein feed was isonitrogenously either rapeseed cake or pea and diets were supplemented with seaweed. The dietary treatments were: rapeseed control K-R (no seaweed), pea control K-H (no seaweed), which were supplemented with 56,9 g dry matter (DM)/d A. nodosum i.e. seaweed 1 (M1- R, M1-H) and 7,8 g DM/d L. digitata i.e. seaweed 2 (M2-R, M2-H). The target iodine content of control diets was 1 mg/kg DM and seaweed diets 4 mg/kg DM. Finnish iodine recommendation for feeds that do not contain goitrogenic compounds is 1 mg/kg DM. Cows had ad libitum access to partial mixed ration that contained grass silage, barley and protein feed. In addition, concentrate was given to cows 1,8 kg/d and contained minerals (300 g/d), molassed sugar beet pulp, molasses and also seaweed in seaweed diets. The forage to concentrate ratio was 65:35. Mineral used in diets was approved for organic production and contained iodine 60 mg/kg DM. Dietary treatments did not affect DM intake. Compared to rapeseed diets, pea diets had a 0,15 kg/d lower crude protein intake, 0,24 kg/d lower crude fat intake and 49,7 µg/d lower iodine intake. Iodine intake increased on average by 63,4 µg when seaweed was added to the diet and the effect was greater when adding L. digitata compared to A. nodosum. Also, milk yield was lower with pea diets than with rapeseed diets. The iodine content of milk was higher with pea diets than with rapeseed diets (324 vs. 117 µg/l). Moreover, the addition of seaweed increased the iodine content of milk (on average +226 µg/l). Based on the results, iodine intake was lower with pea diets than with rapeseed diets, as expected, due to the higher iodine concentration of rapeseed cake. Both seaweeds increased the iodine content of milk, but the transfer of iodine to milk was higher with pea-based diets compared to rapeseed-based diets, due to goitrogenic compounds in the rapeseed cake.
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