nutrition has a significant effect on reproduction and lactation in ruminant. supply of require nutrient of dairy cows and ewes in early lactation is the main challenges that will be considered, since in most cases the animals facing negative energy balance after calving and the beginning of the period of lactation. negative energy balance may sometimes result in reduced livestock production an...

Even though extensive research has examined the role of nutrition on milk fat composition, there is less information on the impact of forages on milk fatty acid (FA) composition. In the current study, the effect of replacing grass silage (GS) with maize silage (MS) as part of a total mixed ration on animal performance and milk FA composition was examined using eight multiparous mid-lactation co...

Decreased milk production of beef cattle grazing endophyte-infected (EI) tall fescue (TF), an important cool season grass in the southeastern United States, can affect calf growth. The objective was to determine whether a thermal or heat-tolerant Bos taurus breed of cattle, Romosinuano (RO), would tolerate EI TF toxins relative to Angus (AN) cattle. Milk production and quality were examined on ...

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 ...

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...

The objective of the present study was to determine the effect of substitution of corn grain with dried citrus pulp (DCP) on milk composition, fatty acids profiles and blood metabolites in Holstein dairy cows. These parameters were measured in a replicated 4 × 4 latin square design experiment using eight Holstein cows. Each experimental period lasted 4 weeks. The four treatments were: control (...

The aim of this study was to evaluate the effect of replacing progesterone injections by progesterone vaginal inserts on productive and reproductive parameters of lactating cows with reproductive problems after prolonged periods of heat stress. Fifteen Holstein cows were randomly assigned to one of three treatments: 1) treated with two progesterone vaginal inserts (P4-INS); 2) treated with prog...

Objective. To determine the associations of BoLA DRB3.2 alleles present in Holstein and BON x Holstein cattle to production and milk quality traits in a dairy herd of Antioquia, Colombia. Materials and methods. Ninety-one cows, 66 Holstein and 25 BxH, were genotyped for the BoLA DRB3.2 gene, through PCR-RFLP technique. Furthermore, the association of the alleles of the gene BoLA DRB3.2 with mil...