AIM The aim of the present investigation was to optimize the age at first use (AAFU) of semen of Murrah breeding bulls, which will help in early selection of bulls under progeny testing program for improving the reproductive performance in the herd. MATERIALS AND METHODS The data on AAFU, conception rate based on first A.I. (CRFAI), overall conception rate (OCR), and birth weight (B.WT) of 57...

The importance of milk proteins and the positive effect of administration of growth hormone (GH) on milk production, and the presence in some dairy cattle lines of greater GH concentrations prompted us to examine the presence of restriction fragment length polymorphism at the GH gene using the restriction enzyme TaqI and to investigate associations between this polymorphism in Simmental cows an...

The present study was conducted to detect polymorphism at growth hormone gene in Karan Fries bulls. A 428 bp fragment of growth hormone gene spanning over 4 exon, 4 intron and 5 exon was amplified and digested with AluI restriction enzyme to identify polymorphism at this locus. Karan Fries bulls were found to be polymorphic at this locus. Two genotypes LL and LV were identified in Karan Fries w...

Besides its nutritional value, bovine beta-casein is a source of bioactive peptides called betacasomorphins produced during digestion of raw or processed milk. It was shown that the betacasomorphin 7 originates only from beta-casein variants A1 or B and may be a significant risk factor in human ischemic heart disease, arteriosclerosis, type I diabetes and sudden infant death syndrome. In this s...

Semen characteristics were evaluated every 2 wk from 7 through 13 mo of age in 31 beef bulls representing six breed groups (Hereford, Angus, Hereford x Angus crossbreeds, Angus x Hereford crossbreds, Red Poll and Brown Swiss). Breeds differed in age at puberty, defined as the age at which an ejaculate was first obtained that contained a minimum of 50 x 10(6) total spermatozoa with at least 10% ...

Evaluating breeding soundness of bulls is an often neglected management practice. Producers may incorrectly believe that bulls that have previously proven fertile are of sound breeding value for the rest of their lives. They may also assume that new bulls are reproductively sound simply because of some vague or implied guarantee by the seller. Unfortunately, neither assumption is correct. Bulls...

Ninety-six bulls, one-third each being Charolais (614lb), Hereford (600 lb) and Hereford-Angus crossbreds (566Ib) were implanted with (1) nothing, (2) Compudose, (3) Synovex or (4) Ralgro. The latter two groups were reimplanted on day 75. Bulls were placed in 12 pens and were fed a high concentrate diet for 118 days. Impants increased liveweight gains by a mean of 34 pounds (6.2 percent) and ca...

The present study was undertaken to assess the relationship between the scrotal circumference and testicular parameters with body weight and age in Tho Tho bulls (Bos indicus), which were maintained at around the villages of National Research Centre on Mithun (ICAR), Jharnapani, Nagaland, India. A total of 32 Tho Tho bulls were selected and divided into four groups according to their age and ea...

The diurnal behavior patterns of feedlot bulls were investigated at 52 degrees N during winter and spring. Two trials were conducted during periods when the daylight portion of the day increased by over 7 h. In trial 1, 324 bulls were observed hourly for 24 h on nine occasions at 2-wk intervals. The average proportions of bulls eating, drinking, standing and lying were 9.8, 1.9, 27.4 and 60.0%,...

Introduction Testicular temperature of bulls must be 2 to 6° C cooler than body temperature to allow normal spermatogenesis and maturation of sperm. Exposure of bulls to increased ambient temperatures results in reduced semen quality (Casady et al., 1953; Skinner and Louw, 1966; Meyerhoeffer et al., 1985). Local heating of the scrotum of bulls for a few days causes a reduction in the number of ...