Browsing by Subject "dairy cattle"
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(2014)In this study the economic values for the breeding goal traits for Finnish Ayrshire cattle were determined by the bioeconomical model. Additionally, the economic value was determined for a new trait, feed efficiency, which was modelled as residual feed intake (RFI). Feed efficiency was added to breeding goals because of intrest in reduction of harmful environmental effects of dairy cattle production. The effect of increasing feed costs on the economic weights was also studied. Economic values were determined by the program ECOWEIGHT. The bioeconomical model included 21 traits, which can be divided a few categories: milk production traits, growth and carcass traits and functional traits (calving difficulty, stillbirth, calf mortality in the rearing period, fertility traits, productive lifetime of cows, incidence of clinical mastitis, somatic cell score (SCS) and residual feed intake (RFI)). Economic values and standardized economic weights were defined for the traits. Profitability of the milk production was negative (?13,3%), when the subsidies were not included in the calculations. Adding RFI didn’t have any effect on the economic values of the other traits and it didn’t change the order of the traits in standardized economical weight. The marginal economic values for RFI of cows and heifers were ?55,8 and ?24,9 €/kg/d, respectively. The highest relative economic weights was found for 305-d milk (36%), protein (14%), fat (9%), mature weight (7%) and calving interval (5%). Relative economic weights for RFI of cows and heifers were 4,6% and 1,5%, respectively. An increase in the feeding costs (10, 30 and 50%) changed the order of the traits in standardized economical weights. The weights of milk production traits were decreased and the weights of growth traits, RFI and calving interval were increased. RFI of cows was the fifth important trait when feeding costs increased 30%. According to the results of this study would be beneficial, especially if the relative im-portance of feed efficiency will increase in the future due to increasing feed costs or in-creasing requirements to mitigate the environmental impact of milk production. However, more research will be needed before adding RFI to the breeding goals.
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(2017)The aim of this master’s thesis was to investigate the potential of reducing enteric methane production from dairy cows by replacing barley grain with oat grain on a grass silage-based diet. The effects of grain species on in vitro methane production, digestibility, pH and volatile fatty acid (VFA) production pattern were investigated and a regression analysis was performed to entangle possible methane mitigating mechanisms of oats. The study was conducted in the laboratory at the Department of Agricultural Research for Northern Sweden in the autumn of 2016. An in vitro gas production system was applied, consisting of 16 diets with two replicates, four blanks and three runs, each with a three-day incubation time. The feed material consisted of eight varieties of barley, eight varieties of oats and timothy silage incubated at a grain/silage ratio of 1:1 on a dry matter basis. Rumen fluid was collected from two cannulated Nordic Red dairy cows after morning feeding. Gas sampling was performed at 2, 4, 8, 12, 24, 32 and 48 hours of incubation, meanwhile VFA-sampling, pH-measurements and sampling of incubation residues were performed at 48 hours. Methane production was estimated as predicted in vivo methane production and stoichiometrically predicted methane production. The in vitro digestibility was determined as true dry matter digestibility (TDMD). Content of indigestible neutral detergent fiber (iNDF) was determined by applying a 12-day in situ incubation in two Ayrshire dairy cows. Oats had a higher content of crude protein, neutral detergent fiber (NDF), iNDF and fat compared to barley, whereas barley had a higher content of starch. Replacing barley with oats decreased predicted in vivo methane production by 9% and stoichiometrically predicted methane production by 11%. Variety within grain was not found to have any significant effect on methane production. True DM digestibility and total VFA production were lower in oat-based diets compared to barley-based diets. No significant differences were observed between the diets considering VFA molar proportions. The pH was lower in barley-based diets compared to oat-based diets. True DM digestibility was the best predictor of methane production. Among grain composition parameters, iNDF content was the best predictor of methane production, followed by NDF. Crude fat content also predicted methane production relatively well. Based on the results of this experiment, it can be concluded that replacing barley grain with oat grain in the diet of dairy cows has a potential to lower methane production predicted in vitro. Furthermore, the methane mitigating effect observed in this experiment is at least partly due to the higher fat content and lower digestibility of oats compared to barley.
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(2015)During early lactation diet is usually rich in protein to stimulate and support milk production. Increased milk production has been connected with negative energy balance and impaired fertility. The aim of this study was to investigate the effects of concentrate crude protein (CP) level to dairy cow silage intake, milk production and energy balance in early lactation. The study was conducted in the experimental barn of MTT Agrifood Research Finland in Maaninka. The experiment started at October 2013 and finished at April 2014. The experiment lasted 70 days starting from parturition day. Fifty-five primiparous or multiparous Holstein and Ayrshire cows were allocated to one of three different CP levels in concentrate (149, 179 or 200 g/kg DM) after parturition. Concentrate allowance was 9 or 13 kg. Silage was fed ad libitum through an individual feeding system. Animals were weighed daily. Body condition score (BCS) was determined when blood samples were taken at 10 days before parturition and 7, 21, 42 and 63 days after parturition. The data were subjected to analysis of variance using the SAS MIXED procedure. Concentrate CP level did not affect silage intake or energy balance. Amino acids digestible from small intestine increased when CP level increased. Increasing CP content of concentrate tended to increase milk and protein yields suggestively. Milk protein yield and milk urea increased when concentrate CP level increased. Concentrate CP level had no significant effect on blood NEFA, BHBA, 3-MH or glucose concentration. There were no significant effects on live weight or BCS change throughout the experiment. Results of this experiment indicate that increasing concentrate CP level improves milk and protein yield in early lactation. In this experiment concentrate CP level did not affect silage intake or energy balance.
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