The conceptual bases of recent NRC publications of nutrient requirements to meet dietary energy needs of growing Holsteins, emphasizing heifers gaining 0.75 kg/d, are described and compared with several world systems and with body composition data. Requirements of Holsteins for net energy for maintenance are generally thought to be higher (from 7 to 20%) than those of British beef breeds. Total...

Farmers' subjective evaluations of their cows' milking speed, scored as "very fast", "fast", "average", "slow", or "very slow", were recorded between 1982 and 1985 under Agriculture Canada's Record of Performance milk recording scheme. For the analysis, scores taken at the beginning (score 1) and the end (score 2) of the lactation were distinguished. Edited data comprised 20,909 records for sco...

A sire-maternal grandsire threshold model was used for genetic evaluation of stillbirth in US Holsteins. Calving ease and stillbirth records for herds reporting at least 10 dead calves were extracted from the Animal Improvement Programs Laboratory database. About half of the 14 million calving ease records in the database had a known livability score, mostly from herds processed by Dairy Record...

Genetic variation in estrus traits derived from hourly measurements by electronic activity tags was studied in an experimental herd of Holstein (n = 211), Jersey (n = 126), and Red Dane (n = 178) cows. Both virgin heifers (n = 132) and lactating cows in the first 4 parities (n = 895 cow parities) were used, giving a total of 3,284 high-activity episodes indicating estrus. The first estrus after...

This study was conducted to evaluate the relationship between milk score (MS) and litter weight at 70 d (LW) for four sheep breeds in the United States. Milk score is a subjective measure of milk production used to assess milk production of range ewes when milk yield cannot be quantitatively determined. Variance components for MS and LW were estimated for each of Targhee, Columbia, Rambouillet,...

CXC chemokine receptors 1 (CXCR1) play a key role in inflammatory response and eventual activation of the innate immunity. Mastitis is a big problem in dairy industry. In the presented study the bovine CXCR1 gene was considered a candidate gene of anti-mastitis defense in Chinese Holsteins. Polymorphism of bovine CXCR1 was investigated and its associations with Somatic Cell Scores (SCS) and mil...

Young sows are subordinate and vulnerable in group-housing systems because they usually lose most fights and suffer more injuries than mature sows at mixing. This study was conducted to evaluate effects of sorting by parity on reducing aggression and associated stress with the aim to improve welfare and performance of first-parity sows in a group-housed system. Sows and gilts (n = 180) from 6 b...