RESUMEN
The objective was to assess the effects of the month of conception, month of calving, sex of the calf, and twins on gestation length (GL) in Holstein cows and heifers in two dairy herds with different milk yields. The study was performed in northeast Czech Republic over a 6-year period on two commercial dairy herds with a mean annual milk production of 11,060 kg per cow in the higher milk-producing herd and 8854 kg per cow in the lower milk-producing herd. Gestation length in cows that conceived in different months of the year was longer in the higher milk-producing herd than that in the lower milk-producing herd throughout the year (P < 0.01), whereas GL in heifers was almost the same in both herds. Gestation length in cows that conceived in different months of the year was longer than that in heifers through the whole year in both herds (P < 0.05). Similar results were found in cows and heifers that calved in different months of the year. Gestation length in cows and heifers that conceived in the first months of the year was longer than in those that conceived in the last months of the year in both herds (P < 0.05). Gestation length in cows and heifers that calved in late fall and throughout winter was longer than in those that calved in spring and summer in both herds (P < 0.05). Gestation length in females carrying male calves was longer than in those carrying female calves (P < 0.0001). Gestation length in cows (P < 0.0001) and heifers (P < 0.05) carrying singles was longer than in those carrying twins in both herds. In conclusion, results indicate that GL in Holstein cattle is associated with the month of conception, month of calving, herd, parity, sex of the calf, and twins.
Asunto(s)
Bovinos/fisiología , Preñez , Animales , República Checa , Femenino , Lactancia , Masculino , Paridad , Embarazo , Preñez/fisiología , Factores Sexuales , Factores de Tiempo , GemelosRESUMEN
The binding (r) of chloramphenicol to serum proteins is significantly lower in patients with chronic renal failure than in normal subjects. Before hemodialysis, the mean r value in patients with chronic renal insufficiency was 0.165 mg/g (+/-0.003) versus 0.188 mg/g (+/-0.004) in healthy individuals. Hemodialysis produced a significant rise in r (to 0.182 mg/g, +/-0.004). Decrease in the serum concentration of albumin in patients with chronic renal insufficiency does not seem to be the sole factor responsible for decreased r.