RESUMEN
First lactation records of 1538 buffalo maintained at the Animal Production Research Institute farms in 1967 to 1990 were used to determine lactation curves for three lactation lengths: > 28 and < 150 d, > 149 d, and > or = 308 d, as well as all records. Daily milk yields were summed by 14-d intervals for analyses. Yields peaked at the first, fifth, sixth, and seventh periods for > 28 and < 150 d, > 149 d, > or = 308 d, and all records. Herd-year-season significantly affected milk yield in all periods. Persistency for all records and three groupings (> 28 d, > 149 d, and > or = 308 d in milk) was highest for the > or = 308-d group (1.02 vs. .85 for > 149 d, .57 for > 28 d, and .47 for all records). Herd-year-season of calving significantly affected persistency in all records and the three subset groupings. Persistency was higher for buffalo calving in spring and summer for all records, records > 28 d, and records > 149 d but in summer and autumn for the > or = 308 d, the correlation coefficient between persistency and milk yield (r = .06) was not significant but was negative with season of calving (r =-.11).
Asunto(s)
Bovinos/fisiología , Industria Lechera/estadística & datos numéricos , Lactancia/fisiología , Envejecimiento , Animales , Egipto , Femenino , Embarazo , Estaciones del Año , Factores de TiempoRESUMEN
6 male and 5 female calves each of Shorthorn X Domiatti crosses and 3 female calves each of the Domiatti breed were fed either the norm (100% allowance) or a lower ratio (80% allowance) between their 28th and 72nd weeks of age. The growth of all animals differed significantly with regard to the different allowance levels but not with regard to the breeds. In the female animals no differences were found in the age and live weight at puberty, the first conception, and calving between the two feeding levels. In the male animals there were no differences in the age at puberty with both feeding levels, though there were significant differences in the live weight at puberty. The semen volume, sperm motion, and sperm concentration were not significantly affected.