We investigated the effect of the amount of body condition loss in the dry period and early lactation in 42 high-yielding Holstein-Friesian cows on milk yield and the share of fatty acids in milk fat. Energy reserves were estimated based on the body condition scoring (BCS) and backfat thickness (BFT). Milk yield and milk composition were determined over 305-d lactation. From d 6 to 60 of lactat...

There are many potential applications of transgenic methodologies for developing new and improved strains of livestock. One practical application of transgenic technology in pig production is to improve milk production or composition. The first week after parturition is the period of greatest loss for pig producers, with highest morbidity and mortality attributed to malnutrition and scours. Des...

The modern dairy cow has been selected over generations for high milk production, with many successful dairy operations averaging over 13,500 kg of milk per lactation cycle per cow. This amount of nutrient output in the form of milk components puts a tremendous amount of pressure on the metabolism of the dairy cow, especially during early lactation. In fact, it is common to all mammals, includi...

in order to estimate the genetic parameters and comparison legendre polynomials for production traits of iranian holstein dairy cattle test-day records of first lactation cows for milk yield, fat yield, protein yield, fat percentage and protein percentage traits were used. these records collected from 2006 to 2010, by the animal breeding center of iran. the genetic parameters were estimated usi...

The effects of melatonin administration and pinealectomy on the milk ejection response were studied in the rat. The amounts of milk obtained by a litter during 1 hr suckling and during an additional 30 min suckling after 1 I.U. of oxytocin injection, following 7 or 8 hr separation from the mother on the 10th or 16th day of lactation, were considered as the naturally ejected milk and the residua...

In discussing whether or not homologous milk is an advantage to the young (Le., whether feeding the young of a species milk of the same species confers an advantage over a substitute derived from milk of another species), we are still largely reduced to the old teleological arguments: the milk of a species is appropriate for the growth of the young of that species, therefore, growth and develop...

The objectives of this study were to analyze the genetic properties of three measures of lactation persistency in Polish Holstein-Friesian cows, and possibly to choose one measure which could be used for estimation of breeding value for lactation persistency in the Polish dairy cattle population. Data included 117,327 first three lactations of 110,141 cows calved in 1995-2009. The lactation cur...

Two experiments were conducted with lactating Angus x Gelbvieh beef cows to determine the effects of postpartum lipid supplementation, BCS at parturition, and day of lactation on fatty acid profiles in plasma, adipose tissue, and milk. In Exp. 1, 36 pri-miparous cows (488 +/- 10 kg of initial BW; 5.5 +/- 0.02 initial BCS) were given ad libitum access to hay and assigned randomly to a low-fat (c...

collected data in animal breeding center of iran from 1983 to 2003 was used to estimate the genetic parameters of milk yield in iranian holstein cattle. genetic parameters were estimated, using single and three trait animal models. records of three lactations were divided into thre esub groups according to average milk yield, climitical regions and herd sizes. all variance components in the thr...

Six groups of Sahiwal-Friesian crossbred cows, namely M50-1, M50-2, M50-3, M56, M63 and M75-1 were evaluated. In total 180 cows were used and milk collected was evaluated for composition and quality. The effect of genotypes was significant (P≤0.05) only for titrable acidity (TA) and milk yield (MY). The M50-1 had the highest milk yield per day (8.73 ± 1.65 kg) but this was not significantly dif...