Analysis of circulating-microRNA expression in lactating Holstein cows under summer heat stress

Influence of sire and sire breed (Gyr versus Holstein) on establishment of pregnancy and embryonic loss in lactating Holstein cows during summer heat stress.

Heat stress has negative effects on pregnancy rates of lactating dairy cattle. There are genetic differences in tolerance to heat stress; Bos taurus indicus (B. t. indicus) cattle and embryos are more thermotolerant than Bos taurus taurus (B. t. taurus). In the present study, the effects of sire and sire breed on conception and embryonic/fetal loss rates of lactating Holstein cows during the Br...

Interrelationships of Heat Stress and Reproduction in Lactating Dairy Cows

Efficient reproductive performance of lactating dairy cattle in tropical/subtropical and arid environments throughout the world is impacted by a multiplicity of factors such as: the physical environment, socialeconomic status of producers, available nutrients, adaptability and genetic composition of cattle, intensive or extensive management systems, and available reproductive technology. Season...

Role of prostaglandins in the development of hyperthermia in heat-stressed, lactating Holstein cows.

Heat stress can have severe effects on the physiology and productive function of lactating dairy cattle. Among the negative effects are hyperthermia, metabolic alkalosis, reduced feed intake, decreased milk yield, and increased embryonic mortality (Ealy et al., 1993; Miller et al., 1999; Ominski et al., 2002). The hyperthermia coincident with heat stress occurs largely because animals cannot di...

Genetic Regulation of Feed Efficiency in Lactating Holstein Cows

Methane prediction in dry and lactating Holstein cows.

Data from six experiments (two with dry cows) were used to predict partitioning of gross energy to CH4 in Holstein cows using selected independent variables, some of which were intercorrelated, and a stepwise backward elimination regression procedure. Methane outputs ranged from 3.1 to 8.3% (mean 5.5) of gross energy intake for 134 dry cow balance trials and from 1.7 to 14.9% (mean 5.2) of gros...