Canadian and US evaluations of Holstein bulls were compared for longevity measures (433 bulls) and somatic cell score (354 bulls). Bulls were required to have a birth year of > or = 1975, daughter information from > or = 20 herds, and a reliability of > or = 50% in both Canada and the US. The number of bulls with longevity evaluations was greater for early years because longevity information wa...

Adipose tissue in the loin muscle area of beef cattle as a marbling factor is directly associated with beef quality. To elucidate whether properties of proteins involved in depot specific adipose tissue were sex-dependent, we analyzed protein expression of intramuscular adipose tissue (IMAT) and omental adipose tissue (OMAT) from Hanwoo cows, steers, and bulls of Korean native beef cattle by li...

Fibre type composition, activities of enzymes such as citrate synthase (CS), 3-hydroxyacyl coenzyme A dehydrogenase (HAD), lactate dehydrogenase (LDH), as well as glycogen, lactate and pH levels were analysed in muscle biopsies (m. gluteus medius) obtained after bullfighting from 10 young and 10 old bulls. No changes were seen in fibre type composition between groups, but the older bulls had hi...

Sequence polymorphisms in the growth hormone (GH) gene and its transcriptional regulators, Pit-1 and Prop-1, were evaluated for associations with growth and carcass traits in two populations of Brangus bulls Chihuahuan Desert Rangeland Research Center (CDRRC, N = 248 from 14 sires) and a cooperating breeding program (COOP, N = 186 from 34 sires). Polymorphisms were SNP mutations in intron 4 (C/...

The effect of castration on endogenous proteinase activity and myofibrillar protein turnover was investigated in cattle. Six each of MARC III composite bulls and steers weighing approximately 210 kg were given ad libitum access to a typical growing diet. At 0, 42, 84, 126, and 168 d, two consecutive 24-h urine samples were obtained. Urine was analyzed for N tau-methylhistidine (N tau MH) and cr...

In many mammal species, androgen levels in males are elevated during periods of mating activity, often to facilitate aggressive behavior between males over access to fertile females. However, this pattern might be less obvious in species with a rather low male-male aggression rate, or in those that are not strictly seasonal breeders. A complex social structure, as well as additional social and ...

Seven batches of 25% water-phase, oil-in-water vaccine were prepared from whole cultures of Tritrichomonas foetus. Two inoculations were given, spaced 6 weeks apart, to virgin heifers and infected bulls. A significant reduction (P less than 0.01) in the duration of infection in vaccinated heifers was seen when they were challenged by being bred to a bull infected with the same isolate as that c...

Throughout the history of development dairy cattle breeding, particular importance has always been attached to identification and rational use record cows. The significance this category breeding is determined not only by individual indicators, but also effect they have on improvement breed herds, primarily through their sons and, a certain extent, as ancestors families. It should be noted that...

The objectives of this study were to examine the growth, DMI, and feeding behaviors of Angus and Hereford bulls; identify the relationships between feeding behaviors and variation in DMI and residual feed intake (RFI); and determine the value of feeding behaviors in predicting DMI. Individual DMI was measured in Angus bulls (n=189; initial BW=427±3.4 kg) and Hereford bulls (n=146; initial BW=41...