Sows that were either fat or lean at farrowing (340 or 280 g of body fat/kg BW, respectively) were offered either a low-protein (LP; 7.9% CP and 15.5 MJ DE/kg as fed) or a high-protein (HP; 19.0% CP and 15.6 MJ DE/kg as fed) diet on an ad libitum basis throughout a 4-wk lactation to test the hypothesis that the amount of milk and its composition are responsive to the supply of endogenous (body ...

The objective of this study was to evaluate the effect of ruminally protected amino acids (RPAAs) and ruminally protected fat (RPF) supplementation on ruminal fermentation characteristics (in vitro) and milk yield and milk composition (in vivo). Fourteen mid-lactating Holstein dairy cows (mean weight 653±62.59 kg) were divided into two groups according to mean milk yield and number of days of p...

Milk fat concentration is variable within and between farms and is modified by genetics, season of the year, and physiological state, but is especially responsive to diet. Synthesis of milk fat is an energy demanding process, but also represents a significant portion of the economic and nutritional value of dairy products. First described over one and a half centuries ago, diet-induced milk fat...

A spline animal model was fitted to 152,103 test-day milk, fat, and protein yield records from 14,423 first-lactation cows. The models included age at calving and the herd-test-month as fixed effects. Model fitting was carried out using Restricted Maximum Likelihood with ASREML. For milk yield, the heritability at 18 d in milk was 0.19, which increased to the maximum estimated value of 0.23 at ...

Maternal lineage effects on milk yield traits, considered indicative of cytoplasmic inheritance, were evaluated with animal models. Cattle were from a selection experiment begun in 1968. Maternal pedigrees were traced to the first female member in the Holstein-Friesian Herdbook; purchased cows entering the herd, considered foundation females, were assigned to maternal lineage groups. All models...

the aim followed in the present study was to investigate the effects of different metabolizable protein (mp) levels on holstein cows, milk yield and composition, and as well on concentration of plasma metabolites in the cow,s early lactation. twenty - four holstein cows(bw 580±23, dim 30±7, parity 2.4±0.5) were randomly assigned to each one of the 4 dietary treatments containing 1) 10.60% (diet...

OBJECTIVE A meta-analysis was conducted to evaluate the effects of supplemental fat containing saturated free fatty acids (FA) on milk performance of Holstein dairy cows. METHODS A database was developed from 21 studies published between 1991 and 2016 that included 502 dairy cows and a total of 29 to 30 comparisons between dietary treatment and control without fat supplementation. Only satura...

To evaluate lactation performance and changes in plasma and fecal lipopolysaccharide (LPS) concentrations in response to the supplementation of Saccharomyces cerevisiae fermentation product (SC), two dairy farms were selected. On each farm, 32 cows in early to mid lactation (21 to 140 DIM) were blocked by parity and days in milk (DIM), and randomly assigned to one of the two treatments within b...

This study explores the biological role of the Fat Mass and Obesity associated (FTO) gene locus on milk composition in German Holstein cattle. Since FTO controls energy homeostasis and expenditure and the FTO locus has repeatedly shown association with obesity in human studies, we tested FTO as a candidate gene in particular for milk fat yield, which represents a high amount of energy secreted ...

The objective of the present study was to determine the effects of rumen-protected choline (RPC) supplementation on body condition, milk production and milk choline content during the periparturient period. Thirty-two Holstein cows were allocated into two groups (RPC group - with RPC supplementation, and control group - without RPC supplementation) 28 days before the expected calving. Cows were...