Browsing by Subject "dairy cow"
Now showing items 1-11 of 11
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(2014)The aim of this study was to investigate the effects of graded amounts of camelina oil on milk fatty acid composition in lactating cows fed diets based on a mixture of grass and red clover silages. The experiment was carried out at the University of Helsinki research farm in Viikki 30th January 2009 – 23th April 2009. Eight multiparous Finnish Ayrshire cows participated in this experiment and four of them were rumen fistulated. Experimental design used was 4 x 4 Latin square. Treatments consisted of concentrate supplements containing various levels of camelina oil (0%, 2%, 4% and 6% on air-dry basis). All concentrates contained camelina expeller (20% on air-dry basis). The cows were offered daily 12 kg of experimental concentrate and silage ad libitum. The experimental periods lasted for 21 days. The first 14 days were adaptation period and the last 7 days formed sampling period. Increase of camelina oil level in the diet linearly decreased forage and whole diet dry matter intake (P?0,002). Camelina oil level did not affect organic matter, NDF and nitrogen whole-tract digestibility (P>0,10). Milk yield and milk protein- and lactose content linearly decreased when camelina oil level increased (P<0,001). Camelina oil level did not affect milk fat yield (P>0,100). Milk fat content (P=0,014) linearly increased and protein content (P=0,032) and urea content (P<0,001) linearly decreased when camelina oil level increased. Camelina oil level did not affect milk lactose content (P>0,100). Increase of camelina oil level linearly worsened milk taste panel scores (P=0,018). Camelina oil level did not affect plasma metabolite concentrations except that of total free fatty acids that linearly increased with camelina oil supplementation (P<0,001). Effects of camelina oil supplementation on rumen pH and rumen fermentation pattern were numerically negligible. Increase of camelina oil level linearly decreased the concentration of saturated fatty acids in milk fat (P<0,001) and linearly increased those of monounsaturated (P<0,001) and polyunsaturated (P<0,002) fatty acids. Increase of camelina oil level linearly decreased the content of mammary de novo synthesised short- and medium-chain 6-14-carbon fatty acid in milk fat (P?0,028). Camelina oil level had no effect on alphalinolenic acid content in milk fat (P>0.100). Increase of camelina oil level linearly increased trans fatty acids and CLA content in milk fat (P?0,008). Camelina oil supplementation did not affect neither the milk fat content of the final product of ruminal biohydrogenation of 18-carbon unsaturates stearic acid nor that of oleic acid (P>0,10). This is possibly due to biohydrogenation not proceeding to the end, ceasing to the last step before stearic acid. Milk fat trans-11 18:1 and cis-9, trans-11 CLA contents linearly increased at remarkably high levels when camelina oil level in the diet increased (P?0,008). This is possibly due to incomplete ruminal biohydrogenation of 18-carbon unsaturated fatty acids. Camelina oil supplement improved milk fat composition by decreasing saturated and increasing the trans-11 18:1 and cis-9,trans-11 CLA content in milk. However, giving camelina oil at high levels decreased silage and whole diet dry matter intake and affected milk production negatively.
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(2022)The intensification of milk production has increased the size of farms and reduced the use of pastures in recent decades worldwide. The interest in farm animal welfare and the climate impact of dairy products is growing. Offering dairy cows full-time pasture access has declined, but there are other possibilities to provide outdoor access for dairy cows. The aim of this study was to evaluate the effects of two outdoor management systems on the feeding behaviors and productivity of lactating dairy cows. This study was conducted at the University of Helsinki research barn’s freestall and adjacent pastureland in Viikki. The experimental design was a replicated 3x3 Latin square. Twenty-seven Ayrshire cows were divided into nine squares. During the experiment, cows went through three 21-day periods. Cows in squares were assigned to the following treatments: partial access to pasture with sufficient forage for grazing (pasture), partial access to pasture without grazeable forage (paddock), and indoor confinement. Milk yield and ECM were greater in the paddock than in the pasture treatment. Part-time grazing led to an energy deficit because pasture cows had the lowest milk yield. Outdoor access reduced the content of saturated fatty acids and increased the content of monounsaturated fatty acids in milk. Pasture cows spent 30% of their outdoor time eating and paddock cows 27%. Paddock cows used 15% of their total eating time eating TMR and 12% attempting to graze. Pasture cows ruminated the most between 12:00 a.m. and 6:00 p.m., and indoor cows ruminated more than outdoor cows between 7:00 a.m. and 5:00 p.m. Outdoor cows ruminated more than indoor cows from 6:00 p.m. to 11:00 p.m. The cows on the pasture produced less methane per day than the paddock cows. However, methane production in g/kg ECM was not different among groups. According to this study, grazing seems to be a motivating activity for dairy cows. Providing TMR outdoors can be beneficial for the welfare of dairy cows because it enables a choice between feeds and helps to maintain milk yields. Partial outdoor access changed the diurnal pattern of rumination but not the total time used for rumination. There were no differences in milk’s polyunsaturated fatty acid contents between treatments, but eating fresh grass modified the cow’s milk to be healthier.
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(2023)Herd sizes have grown in Europe which has decreased pasture access. Farmers see pasture as hard to implement, but there are alternative ways to provide outdoor access. Pasture access has many benefits for dairy cows welfare and some benefits can be achieved with alternative outdoor areas. The aim of this study was to evaluate the effects of two outdoor management systems on the lying behavior, injuries, hygiene, and locomotion of lactating dairy cows. This study was conducted at the University of Helsinki Viikki research freestall barn with adjacent pastureland in Finland. The experimental model was 3 x 3 Latin square within 21-day periods. Twenty-seven primi- and multiparous Nordic red cows was divided into 9 squares based on parity, milk production and locomotion score. Cows were assigned to the treatments which were: 1) partial outdoor access with grazeable forage (pasture), 2) partial outdoor access with no grazeable forages (outdoor paddock), and 3) indoor confinement (control). Cows spent more time standing than lying on pasture and paddock. Cows spent 32% of their time lying on paddock and 40% lying on pasture. There was no difference on locomotion or injuries among treatments. However, hock injuries occurred more than knee injuries. There was no difference between hygiene among treatments. However, flank hygiene tended to be dirtiest when housed indoor. According to this study there are no difference on cows hock and knee injuries and locomotion whether cows are housed in free stall with part-time access to pasture or paddock. This study indicates that cows with part-time access to pasture or outdoor paddock does not improve a suitable indoor environment. Further research on whether longer exposure to each treatment would have an effect is needed.
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(2017)In dairy cattle, milk flow is an important functional trait which impacts production. Milk flow can be measured accurately by electronic milking meters (EMM) and robots. It is necessary to understand the implications of the transition from the use of subjective scores (milkability, from very slow - 1 to very fast - 5) to objective measurements (milk flow, kg/min), as well as the genetic (co)variation of the traits and with production and health traits. Records from Finnish Ayrshire primiparous cows were analysed for milkability, milk flow, annual milk yield and somatic cell count (SCC). Milk flow was recorded by Tru-Test (EMM) and the Lely robot milking systems. A total of 64 696 cows were analysed for milkability, 1618 cows for Tru-Test and 2232 cows for Lely. To estimate variance components, heritability, genetic and phenotypic correlations, both single and two-trait animal models were fitted and analysed under REML using the DMU software. Heritability of milkability was 0.25 (standard error 0.01). For milk flow, heritability was 0.41 (0.08) and 0.52 (0.08) for Tru-Test and Lely, respectively. The genetic correlations with milk yield were 0.10 (0.04), 0.43 (0.14) and 0.37 (0.14), and with SCC, 0.50 (0.04), 0.42 (0.17) and 0.35 (0.17) for milkability, Tru-Test and Lely, respectively. Common sires provided a way to find the correlation between milkability and milk flow in the absence of common records; the results were positive but low. In conclusion, selection for milk flow is more efficacious than for milkability demonstrating the influence of quality and volume of recording on estimating heritability and genetic correlation.
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(2019)Kivennäis- ja hivenaineet ovat lypsylehmälle välttämättömiä elintoimintojen ja tuotannon ylläpitoon. Härkäpavun siementä voidaan käyttää valkuaisen lähteenä ja koko kasvustoa säilörehuna, mutta niiden hivenainekoostumusta ei tunneta yhtä hyvin kuin rypsirouheen ja nurmisäilörehun. Tutkimuksessa verrattiin lypsylehmän kivennäis- ja hivenaineiden saantia ja sulavuutta härkäpapusäilörehusta ja härkäpavun siemenestä nurmisäilörehuun ja rypsirouheeseen. Tutkielmassa tarkasteltiin kahta koetta, jotka oli tehty Viikin opetus- ja tutkimustilalla vuosina 2014 ja 2015. Molemmissa kokeissa oli 8 Ayrshire-rotuista lypsylehmää. Kokeet toteutettiin kaksinkertaisina 4x4 latinalaisina neliöinä, joissa oli neljä ruokintaa neljänä kolmen viikon jaksona. Koeasetelmat olivat 2x2 faktoriaalisia. Ensimmäisessä kokeessa faktoreina olivat säilörehun kasvilaji (nurmi tai 1:1 nurmi+härkäpapu-kevätvehnä) ja väkirehun raakavalkuaispitoisuus (175 tai 200 g/kg ka). Toisessa kokeessa faktoreina olivat valkuaistäydennys eri lähteistä (rypsirouhe tai härkäpapu), sekä näiden osittainen korvaaminen Spirulina platensis mikrolevällä. Kokeen 2 koeruokinnat olivat isonitrogeenisiä valkuaisrehujen suhteen. Kokeessa 2 kaikissa koeruokinnoissa oli sama pitoisuus kaupallista kivennäisrehua ja kokeessa 1 kivennäislisä oli täysrehuissa. Härkäpapusäilörehuseos sisälsi enemmän kivennäisaineita, mutta vähemmän hivenaineita kuin nurmisäilörehu. Härkäpavun siemen sisälsi 70 % enemmän kuparia kuin rypsirouhe. Härkäpapusäilörehuseos lisäsi eri kivennäisaineiden saantia 1-6 %, mutta vähensi hivenaineiden, kuten raudan ja mangaanin saantia 5-7 % verrattuna nurmisäilörehuun. Härkäpavun siemen lisäsi kuparin saantia 9 %, mutta pienensi magnesiumin, rikin, raudan, mangaanin ja seleenin saanteja 2-14 % verrattuna rypsirouheeseen. Härkäpavun lisääminen ruokintaan kokoviljasäilörehuna tai kokonaisena siemenenä ei vaikuttanut kivennäis- tai hivenaineiden sulavuuteen. Härkäpapusäilörehu tai härkäpavun siemen eivät eronneet merkittävästi nurmirehusta tai rypsistä hivenaineiden lähteinä. Härkäpapu ei sisältänyt mitään kivennäis- tai hivenainetta haitallisen suurta tai hälyttävän pientä määrää.
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(2020)Faba bean (Vicia faba) has potential as a domestic supplemental protein feed, as its seeds are rich in crude protein and starch. However, faba bean protein is low in methionine and highly degradable in the rumen, which reduces its nutritional value. The rate of protein degradation can potentially be decreased by industrial heat and steam treatment. The aim of the study was to investigate how feed industrial processing and methionine supplementation can affect the milk yield and milk composition of dairy cows. The study was conducted at the research farm of the University of Helsinki in Viikki from 6.1.2018 to 21.4.2018. Five multiparous Finnish Ayrshire cows with ruminal fistulas participated in the study, which utilized a 5x5 Latin square study design with three-week trial periods. The five experimental treatments consisted of the following isonitrogenous protein feeds: rapeseed meal (RR), milled faba bean (HJ), roasted (industrial heat treatment) faba bean (HR) and methionine-supplemented (15 g/day omasal infusion) faba bean feeds HJM and HRM. The cows were fed TMR (total mixed ratio) ad libitum. TMR was based on first cut timothy and meadow fescue grass silage (D-value 706 g/kg dry matter), including a mixture of barley-oats, sugar beet pulp and a mineral supplement. The share of concentrate in the dry matter of TMR was 38 %. Faba bean feedings (HJ, HJM, HR, HRM) increased dry matter intake by an average of 1.6 kg/day compared to rapeseed feeding, but this had no effect on milk yield, which averaged 27.7 kg/day in the experiment. Crude protein and starch intakes were higher in faba bean feedings compared to rapeseed feeding. Rapeseed meal contained more fat than milled and roasted faba beans, which increased total fat intake in rapeseed feeding. Faba bean feedings increased the digestibility of crude protein and the protein content of milk compared to rapeseed feeding. Roasting of faba beans tended to increase milk and lactose yields (HJ, HJM vs. HR, HRM). However, methionine supplementation had no effect on milk or protein yield (HJ, HR vs. HJM, HRM). Faba bean feedings increased the content of saturated de novo fatty acids in milk fat and decreased the content of long-chain mono- and polyunsaturated fatty acids compared to rapeseed feeding. Feeding had little effect on rumen fermentation or plasma energy metabolites. According to this study, faba beans were palatable as a supplementary protein feed and it was possible to replace rapeseed meal by milled or roasted faba beans without a decrease in total dry matter intake or milk yield. Roasting of faba bean tended to increase milk yield compared to milled faba bean. Faba bean feeds increased the content of saturated de novo fatty acids and reduced the content of unsaturated fatty acids. Methionine supplementation had no effect on milk production in this study.
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(2014)The aim of this study was to investigate dairy cow performance on faba bean compared to rapeseed meal on silage based diets. Increasing use of grain legumes may improve selfsufficiency of feed protein. The study was conducted at the research farm of University of Helsinki. In the experiment, eight multiparous Finnish Ayrshire cows were used. Four of them were fitted with rumen fistula. In the beginning of the experiment, cows were 100 (± 51) days in milk. Replicated 4x4 Latin square design was used: the other square consisted of cows with rumen fistulas and the other of intact cows. Treatments of the study were concentrate feeds as follows: control (no protein supplement), rapeseed meal, faba bean and mixture of rapeseed meal and faba bean. Concentrates were fed at a rate of 14 kg/d and silage was given ad libitum. Concentrate feeds including protein supplement were isonitrogenous crude protein content being approximately 200 g/kg DM. Protein supplementation increased silage intake (2,4 kg/d) and milk production (1,6 – 4,9 kg/d). Protein supplementation decreased milk fat content (41,2 vs. 45,3 g/kg DM) but increased milk protein content (35,5 vs. 34,3 g/kg). Feed nitrogen utilization to milk, AAT and ME utilizations and ECM yield to feed intake -ratio were decreased on protein supplementation. In this experiment however rapeseed meal did not give responses of same level as was expected according to results of earlier experiments. Diets including faba bean increased silage intake and milk production compared to rapeseed meal diet. Rapeseed meal diet decreased silage intake 2,7 kg and milk yield 2,5 kg compared with faba bean diet. Mixture of rapeseed and faba bean resulted in the highest milk production being 2 kg more than on average on rapeseed meal and faba bean diets. Utilization of ME and ECM yield to feed intake –ratio were increased with rapeseed meal diet. According to this study rapeseed meal as a protein supplement can be substituted by faba bean in dairy cow diets on silage based diets.
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(2011)The aim of this study was to develop mathematical energy balance models for early and middle lactation period of dairy cows. The traits for predicting were information of diet, feed, milk production, milk composition, body weight and body condition score. This study was a part of development work of KarjaKompassi-project. The data used in this study was based on 12 feeding experiments performed in Finland. The complete data from the studies included 2647 weekly records from multiparous dairy cows and 1070 weekly records from primiparous dairy cows. The data was collected from calving to 8-28 weeks of lactation. Three-fourths of the totals of 344 dairy cows were Finnish Ayshire cows and the rest of the cows were Friesian Cattle. The cows were fed by the Finnish feeding standards. The data was handled by the Mixed-procedure of the SAS-programme. The outliers were removed with Tukey´s method. The relationship between energy balance and predictor traits was studied with correlation analysis. The regression analysis was used to predicting energy balance. To quantify the relationship of lactation day to energy balance, 5 functions were fitted. The random factor was a cow in the experiment. The model fit was assessed by residual mean square error, coefficient of determination and Bayesian information criterion. The best models were validated in the independent data. Ali-Schaeffer achieved the highest fit functions. It was used by the basal model. The error in every model grew after the 12th lactation week, because the number of records decreased and energy balance turned positive. The proportion of concentrate in the diets and concentrate dry matter intake index were the best predictors of energy balance from traits of diet. Milk yield, ECM, milk fat and milk fat-protein ratio were good predictors during lactation period. The RMSE was lower when ECM was standardized. The body weight and body condition score didn’t improve the predictive value of the basal model. The models can be used to predict energy balance in the herd level, but they are not applicable for predicting individual cow energy balance.
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(2019)Siirtyminen ummessaolokaudelta tuotoskaudelle on lypsylehmälle haastava ajanjakso, jolloin tapahtuu monia aineenvaihdunnallisia muutoksia. Tunnutusruokinnassa dieetin väkirehun osuutta lisätään muutamia viikkoja ennen poikimista, jotta lehmä ja sen pötsi sopeutuisivat poikimisen jälkeiseen, runsaasti energiaa sisältävään ruokintaan. Tutkimuksen tavoitteena oli selvittää tunnutusruokinnan vaikutusta tuotoskauden alun maito-tuotokseen, maidon koostumukseen, kuiva-aineen syöntiin ja eläimen energiatasetta kuvaaviin veriparametreihin hyödyntäen aikaisemmin julkaistuja tieteellisiä tutkimuksia. Meta-analyysin aineistona käytettiin 20 vertaisarvioitua tutkimusta, joissa ummessaolokauden ruokinnan solunsisällyshiilihydraattien (SSHH) pitoisuutta muutettiin aikaisintaan 30 päivää ennen odotettua poikimista. Tunnutusdieetin SSHH- ja NDF-pitoisuuksien yhteyttä maitotuotokseen, maidon koostumukseen, kuiva-aineen syöntiin sekä veren NEFA (vapaat rasvahapot)- ja BHBA (β-hydroksivoihappo)-pitoisuuksiin tarkasteltiin käyttämällä regressioanalyysiä sekä lineaarista ja toisen asteen sekamallia. Aineiston luokittelevina tekijöinä käytettiin tunnutusdieetin pääasiallisen karkearehun tyyppiä (maissisäilörehu, nurmisäilörehu) ja kontrollidieetin SSHH-pitoisuutta (alle 250 g/kg ka, yli 250 g/kg ka). Väkirehun lisäämisen vaikutusta verrattuna pelkästään nurmisäilörehua sisältävään tunnutuskauden ruokintaan tutkittiin Mix 2.0 PRO ohjelman Random-mallilla. Tunnutusdieetin SSHH-pitoisuuden lisääminen ja NDF-pitoisuuden vähentäminen pienensi veren NEFA-pitoisuutta ennen poikimista sekä suurensi hieman maidon valkuaispitoisuutta ja valkuaistuotosta. NDF-pitoisuuden lisääminen pienensi suuntaa antavasti EKM- ja valkuaistuotoksia. Toisen asteen mallissa SSHH-pitoisuuden vaikutus poikimisen jälkeiseen kuiva-aineen syöntiin oli käyräviivainen ja vaihteli dieetin SSHH-pitoisuuden mukaan. Dieetin SSHH-pitoisuuden ja karkearehutyypin välillä ei havaittu tilastollisesti merkitseviä yhdysvaikutuksia maitotuotokseen, maidon koostumukseen, kuiva-aineen syöntiin tai veriparametreihin. Kun tunnutusdieetin SSHH-pitoisuuden lähtötaso oli vähintään 250 g/kg ka, SSHH-pitoisuuden lisääminen paransi hieman maitotuotosta ja poikimisen jälkeistä kuiva-aineen syöntiä. Väkirehun lisääminen pelkästään nurmisäilörehua sisältäneeseen tunnutuskauden dieettiin suurensi maidon rasvapitoisuutta ja rasvatuotosta. Tunnutusruokinnan vaikutukset maitotuotokseen, maidon koostumukseen ja kuiva-aineen syöntiin olivat pieniä, mutta veren NEFA-pitoisuuden pienentymisellä ennen poikimista voi olla positiivisia vaikutuksia lehmän terveyteen.
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(2020)Milk fat contains a lot of (70–75 %) saturated fat, which is connected to Finnish public heart and coronary diseases. However, it is possible to alter the fatty acid composition of milk fat by giving cows lipid supplements such as crushed rapeseeds. The aim of this pilot study was to investigate how the lipids of crushed rapeseeds affect dairy cow’s milk fatty acid composition. The effects of rapeseed lipids on saturated and unsaturated fatty acid concentrations in milk fat were studied in particular. Additionally, it was investigated how dietary lipids affect cows’ dry matter (DM) intake and milk production as it is known that high amounts of lipids can reduce DM intake and fiber digestion in the rumen. The study consisted of two successive three week long periods of which the first one was control period and the second one test period. There were six ayrshire cows which had been on average 181 days in milk at the beginning of the study. The cows were given partial total mixed ratio (pTMR) containing grass silage as forage (60 % of diet DM) during the whole study. Concentrates comprised cereals, rapeseed meal, molassed sugar beet pulp and mineral supplements. Control diet’s barley was replaced by oats and most of the rapeseed meal was replaced by crushed rapeseed in the test diet. Crushed rapeseed was added 160 g/kg pTMR DM. Cows were also given complete feed 3kg/day at milkings. Lipids of crushed rapeseeds reduced the concentration of saturated fatty acids by 20 % in milk fat. Of all the saturated fatty acids, palmitic acid (C16:0) was decreased by 38 % and stearic acid (C18:0) was increased by 94 %. Of these two saturated fatty acids, C16:0 is linked to higher total plasma cholesterol levels whereas C18:0 is considered to have a neutral effect in humans. The concentration of monounsaturated oleic acid (cis-9 C18:1), which is known to be hypocholesteremic, increased by 78 % in milk fat. Test diet caused decline in DM intake and milk production. It is likely that the milk production decreased partly because the cows were in declining milk production phase. Test feed decreased the apparent digestibility of neutral detergent fiber (NDF), because the amount of rapeseed lipids in the diet was high (48 g/kg diet DM). Crushed rapeseeds suit excellently to alter dairy cow’s milk fatty acid composition. The amount of lipid supplementation should not be too high in order to avoid decreases in DM intake and NDF digestibility as occurred in this study.
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(2019)Sulavuustutkimuksen avulla pyritään arvioimaan eläinten ravintoaineiden tarvetta, kehittämään rehujen koostumuksia ja minimoimaan eläintuotannon ympäristövaikutukset. Eläimen rehunsyönnin ja sonnan kokonaiskeruun avulla laskettua sulavuutta käytetään laajasti, mutta menetelmään liittyy virhelähteitä ja ongelmia. Merkkiaineen käyttö sulavuuden tutkimisessa poistaa kokonaiskeruun tarpeen, mutta se ei ole myöskään ongelmaton. Sisäiset merkkiaineet ovat aineita, joita on luontaisesti rehussa, kuten piioksidi, ligniini, happoon liukenematon tuhka (AIA) ja sulamaton neutraalidetergenttikuitu (iNDF). Ulkoiset merkkiaineet ovat rehuun lisättäviä reagoimattomia valmisteita, kuten liukenemattomia metallioksideja, muovia, kumia tai väriaineita. Tämän tutkimuksen tavoitteena on verrata lypsylehmillä iNDF:n ja AIA:n avulla laskettuja sulavuuksia käyttäen aineistona aiemmin AIA:lla tehtyjä sulavuustutkimuksia. Tutkimusaineistona oli viisi Viikin opetus- ja tutkimustilan navetassa vuosina 2013–2015 tehtyä ruokintatutkimusta. Lehmien poikimisesta oli 100–212 päivää. Koeasetelmat olivat pääasiassa kahden neliön latinalaisia neliöitä. Ruokintakeskiarvoja aineistossa oli 21. Rehu- ja sontanäytteistä määritettiin iNDF nailonpussimenetelmällä uittamalla näytepusseja 12 vrk kahden fistelöidyn lehmän pötsissä. Ravintoaineiden sulavuudet laskettiin iNDF-merkkiaineella ja orgaanisen aineen sulavuuksille laskettiin suhdeluku iNDF-sulavuus/AIA-sulavuus. Lisäksi laskettiin sonnan määrä ja sonnassa erittyneen iNDF:n osuus syödystä iNDF:stä (recovery). Aineistosta laskettiin koeruokintojen minimi ja maksimi, keskiarvo sekä keskihajonta. AIA- ja iNDF-merkkiaineella saatujen sulavuusarvojen välistä yhteyttä testattiin yksinkertaisella regressioanalyysillä. Lisäksi analysoitiin sekamallin regressioanalyysillä mitkä rehuannosta kuvaavat laatuparametrit selittivät parhaiten AIA- ja iNDF-sulavuuksien eroa. Tutkimusaineiston rehujen iNDF-pitoisuudet vaihtelivat 58–146 g/kg ka ja iNDF:n osuus NDF:stä 136–318 g/kg NDF. Koeruokintojen AIA-pitoisuudet vaihtelivat 8,6–14,9 g/kg ka ja iNDF-pitoisuudet 50,8–132 g/kg ka. Aineiston ruokintakeskiarvojen AIA:lla määritetty orgaanisen aineen sulavuus vaihteli 0,646–0,760, kuiva-aineen syönti 18,2–25,8 kg ka/pv, energiakorjattu maitotuotos 24,9–38,4 kg/pv ja väkirehun osuus 42,1–53,0 % kuiva-aineesta. Ravintoaineiden iNDF:llä määritetyt sulavuudet olivat keskimäärin pienempiä kuin AIA-sulavuudet. Orgaanisen aineen iNDF- ja AIA-sulavuuksien keskimääräinen suhdeluku oli 0,959 ja keskimääräinen erotus 0,028. Keskimäärin sonnassa erittyneen iNDF:n osuus syödystä iNDF:stä oli 0,922. Regressioanalyysin mukaan eri merkkiaineilla määritetyissä sulavuuksissa oli suurin ero rehuannoksen sulavuuden ollessa matala, mutta ero pieneni sulavuuden parantuessa. Parhaiten iNDF- ja AIA-sulavuuksien suhdelukua selitti dieetin iNDF-pitoisuus. Mitä suurempi dieetin iNDF-pitoisuus oli, sitä pienempi oli orgaanisen aineen sulavuus iNDF:llä määritettynä verrattuna AIA:lla määritettyyn. Tutkimuksen perusteella iNDF:llä ja AIA:lla saatujen sulavuustulosten välinen suhde vaihtelee riippuen rehuannoksen ominaisuuksista. Tutkielman aineistossa iNDF:n käyttö sisäisenä merkkiaineena vastasi AIA:lla saatuja sulavuustuloksia sitä paremmin mitä pienempi rehuannoksen iNDF-pitoisuus oli ja mitä parempi rehuannoksen sulavuus oli.
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