The aim of this paper was to study the polymorphisms of bovine growth hormone gene. The authors genotyped 363 Hungarian Holstein-Friesian bull dams from 6 farms all over the country. Two variants (L and V) of the bovine growth hormone gene digested with AluI enzyme were identified in the experiment. Genotyping was carried out by PCR-RFLP method. The frequency data of L and V allele was 0.93 and...

The present study was taken to characterize molecular weights of sperm specific polypeptides antigenic to rabbits and calf with the aim to assess their immunoreactivity with IgG antibodies in sera from immuno-infertile cows. Seropositivity for antisperm IgG antibodies in 75 repeat breeder and 15 pregnant control cattle was tested by cellular ELISA using washed spermatozoa antigen from 4 bulls. ...

Genomic evaluations are calculated using deregressed predicted transmitting abilities (PTA) from traditional evaluations to estimate effects of single nucleotide polymorphisms. The direct genomic value (sum of an animal's marker effects) should be consistent with traditional PTA, which is the case for bulls. However, traditional PTA of yield traits (milk, fat, and protein) for genotyped cows ar...

The response of dairy bulls to the urine of cows in various stages of the reproductive cycle was quantified by presenting 200 ml of urine in a stainless steel bowl to the stanchioned bulls for 10 min. Estrous mucus was also presented in the same manner. Sniffs, nose licks and flehmen responses were recorded. Of 15 bulls tested only 7, or 47%, met the criteria of two flehmens in response to estr...

The reproductive performance of Angus (A), Polled Hereford (PH) and Santa Gertrudis (SG) bulls was compared when exposed to 40 cows/bull vs 80 cows/two bulls during a 90- to 95-d breeding period on pasture. Cows were A, PH and SG straightbreds and crossbreds of these breeds. Each year, cows were allotted at random within breed composition and age of dam to breeding groups. A replicate consisted...

Characteristics of progeny-test (PT) programs of artificial insemination (AI) organizations in the United States were examined for changes since 1960. Mean number of bulls that were progeny tested annually by major AI organizations during the mid 1990s was 11 for Ayrshires, 24 for Brown Swiss, 21 for Guernseys, 1261 for Holsteins, 112 for Jerseys, and 3 for Milking Shorthorns. Mean parent age a...

-Bull trout Salvelinus confluentus and other salmonids in the Pacific Northwest are believed at risk of local and regional extinctions because of ongoing habitat loss and fragmentation . Biologists have focused on defining and protecting critical stream channel characteristics, but there is little information regarding the scale or spatial geometry of habitat that may be necessary for the speci...

Grass tetany in cattle has been associated with the consumption of early spring forages high in potassium (K) and low in magnesium (Mg). Alterations in serum Mg and K may affect intermediary carbohydrate metabolism, resulting in hypoglycemia and ketosis that often accompany grass tetany. We investigated these interrelationships by infusing potassium chloride (KC1) intravenously in normal (plasm...

Crossbred (Bos taurus) yearling beef bulls were assessed for breeding soundness and physical traits prior to multi-sire natural mating at pasture. Bulls (n = 60) were assigned to six groups of nine or 10 bulls and two bull-groups were rotated on 14-day intervals during a 63-day mating season in each breeding herd (n = 3) of 191-196 cows. The remaining bulls (n = 14) were maintained under simila...

Introduction Artificial insemination provides a method to inseminate a large number of females to a single sire selected and proven to be an industry leader for economically relevant traits. Thus, genetic change in a herd can occur quickly through the use of artificial insemination. With natural service, herd bulls are also selected for economically relevant traits but are limited on the number...