Holstein bulls were assigned to sampling categories (AI stud, AI nonstud, or non-AI) based on bull code, controller number, and age at semen distribution. The AI stud bulls were sampled through traditional progeny-testing programs of 13 AI organizations; AI nonstud bulls had AI semen collection reported by another organization or by multiple organizations. The non-AI bulls had no reported AI se...

To determine the effects of location and season on growth of bulls, Hereford bulls from Montana (MH; n = 15) and Nebraska (NH; n = 15) and Brahman bulls from Texas and Louisiana (BB; n = 18) were moved to three locations: Montana (MT), Nebraska (NE) or Texas (TX). Each location received 5 NH, 5 MH and 6 BB. Control bulls (not relocated) were maintained at each location. All bulls were pubertal ...

A study was conducted to determine the effect of serving capacity (SC) on sexual behavior of yearling bulls during single- and double-sire pasture matings. Approximately 60 crossbred virgin bulls were subjected to 3 SC tests, and 20 bulls were selected that were similar in age, BW, testes size and semen quality. Ten bulls were high SC (greater than or equal to 3 services/test) and 10 bulls were...

the aim of this study was to investigate the comparison between some seminal plasma parameters and age of the bull. concentrations of various biochemical parameters like fructose, glucose, total proteins, albumin and inorganic ions including na, k and cl ions of seminal plasma of breeding sahiwal bulls of different ageswere assessed. methods: 40sahiwal bullsdivided into 4 age groups.semen (2ml ...

Progeny-test (PT) programs of US artificial-insemination (AI) organizations were examined to determine timeliness of sampling, PT daughter distribution, rate of return of PT bulls to widespread service, and genetic merit of PT bulls compared with AI-proven and natural-service (NS) bulls. Bull age at semen release and at birth and calving of PT daughters was documented by breed (Ayrshire, Brown ...

BACKGROUND In humans, it is now well documented that rising paternal age is correlated with decreased sperm DNA integrity and embryonic developmental failures. On the other side of the coin, it is also reported that very young fathers such as teenagers carry an increased risk of adverse birth outcomes. These observations suggest that, at least in humans, there is an age window for optimal sperm...

A total of 5,909 scrotal circumference and 5,373 tesricular consistency (tonometer) measurements were made on Holstein bulls in seven artificial insemination studs. Comparable measurements were made on 339Angus bulls. The multiple regression equation, Y = -4.67 + 47.26 log X 1 1 . 7 4 (log X)2), where ~f is scrotal circumference in cm and X is bull age in months, described the high rate of test...

The objective of this study was to determine whether yearling bulls, when pastured with cows, reduced the duration of postpartum anestrus to the same extent as did mature bulls. This experiment was conducted over a 3-yr period. Cows were stratified by parity group to achieve 37% 2-yr-old and 63% mature (> 2-yr-old) cows within each treatment group (approximately 50 cows per treatment per year)....

T evaluation of bulls for breeding soundness is an effective and reliable way to identify bulls that are potentially poor breeders. This management technique can be used to greatest advantage if culling occurs before bulls are turned out with females. Also, the evaluation is an important means available to the producer for predicting bulls with satisfactory to excellent potential. This informat...

Present study analyzed the changes in peripheral blood testosterone concentrations and testicular cytogram in relation to age and semen quality in crossbred males. Three different age groups of crossbred males viz. bull calves (6 months, n = 5), young bulls (15 months, n = 5) and adult bulls (4 to 6 years, n = 8) were utilized for the study. Testicular fine needle aspiration cytology technique ...