Cow attributes, herd management, and reproductive history events associated with the risk of nonpregnancy in cow-calf herds in Western Canada.
To identify herd management and cow characteristics associated with the reproductive success of cow-calf herds in Western Canada, 33,391 beef cows were followed from the beginning of the breeding season in 2001 through pregnancy testing in 2002. Breeding management and cow-level risk factors such as age, body condition score (BCS), and previous reproductive history, were measured through a series of herd visits by project personnel and records maintained by the herd owner. Pregnancy status was measured in 205 herds in the fall of 2001 and again in 200 herds in the fall of 2002. Cows least likely to be pregnant in the fall of the year were 10 years old or older, exposed to a bull less than 84 days, had a BCS ≤5 of 9 at pregnancy testing, <5 of 9 before calving, and lost condition between calving and the start of the breeding season, or had a prebreeding BCS <5 of 9 with a loss of condition between breeding and pregnancy testing. Other factors identified that decreased the likelihood of pregnancy in at least one of the 2 years included being a heifer or being a cow exposed to breeding after her first calf, and using a single bull on breeding pasture. Cows vaccinated for bovine viral diarrhea virus and infectious bovine rhinotracheitis and bred on community pastures were more likely to be pregnant than cows that were not vaccinated and bred on community pastures. Cows bred on community pastures that were not vaccinated were also less likely to be pregnant than cows that were not on community pastures regardless of vaccination status. Calving-associated events such as twin birth, Cesarean section or malpresentation, problems such as uterine prolapse or retained placentas, abortion or calf death within 1 hour after birth, or calving late after the start of the breeding season, were also associated with fewer pregnancies after accounting for all other factors.
Factors associated with serum vitamin A and vitamin E concentrations in beef calves from Alberta and Saskatchewan and the relationship between vitamin concentrations and calf health outcomes
Abstract: The study objectives were to identify factors associated with serum vitamin A and vitamin E concentrations in beef calves less than 1 mo old and to examine associations between vitamin concentrations and health outcomes. Serum vitamin A concentrations were highest in calves more than 4 d old, with serum immunoglobulin G concentrations > 19 g L-1, from cows without perinatal health problems, and born where precipitation in the previous growing season was ≥200 mm. Serum vitamin E was highest in calves more than 4 d old, born earlier in the calving season, not born to heifers, and that received selenium and vitamin E injections at or shortly after birth. After accounting for other risk factors, calves with serum vitamin A less than 0.14 µg mL-1 were 2.8 times more likely to die (P = 0.02), and calves with serum vitamin E less than adequate for their age (2–7 d old, <0.8 µg mL-1; >7 d old, <0.5 µg mL-1) were 3.2 times more likely to be treated for enteritis than calves with higher concentrations (P = 0.0001). Drought conditions, dam peripartum health problems, and inadequate colostrum intake contribute to low vitamin A and vitamin E concentrations and adverse health outcomes in beef calves.
Induction of parturition in conjunction with antibiotic treatments
Abstract Parturicion was induced in pregnant beef cows and heifers with 15 mg of flumethasone to test: 1) the effects of an orally active antibiotic on flumethasone induction of parturition success rate and incidence of retained placenta and 2) the effects of injectable long acting and orally active antibiotics on subsequent fertility and offspring performance. Gestation length and birth weight were not significantly changed. There were no significant differences among calving ease scores even though induction significantly improved vigor. Induction caused a significant increase in the incidence of retained placental membranes. Pregnancy rate (P