ABSTRACT
Foram analisadas as características do sêmen obtido de 250 touros de raças zebuínas e 144 touros de raças taurinas em uma central de inseminação artificial, no Sudeste brasileiro. Consideraram-se dois períodos de colheita: chuvoso e seco, ambos com temperaturas elevadas (>19,0º C). Também foram estudadas as causas dos descartes e a congelabilidade do sêmen. O sêmen das raças taurinas foi superior ao das raças zebuínas nos aspectos turbilhonamento, motilidade e concentração espermática e inferior quanto ao volume (P<0,05). O descarte foi maior na estação chuvosa (P<0,05). O sêmen descartado por características físicas foi maior nas raças zebuínas e por características morfológicas nas raças taurinas (P<0,05). A congelabilidade do sêmen das raças taurinas foi superior à dos touros das raças zebuínas (P<0,05).
Subject(s)
Cattle , Insemination, Artificial/methods , Semen Preservation/trends , Semen Preservation/veterinary , AndrologyABSTRACT
A longitudinal and prospective study was carried out at two state-operated maternity hospitals in Belo Horizonte during 1996 in order to assess the weight of preterm appropriate-for-gestational-age newborns during the first twelve weeks of life. Two hundred and sixty appropriate-for-gestational-age preterm infants with birth weight <2500 g were evaluated weekly. The infants were divided into groups based on birth weight at 250-g intervals. Using weight means, somatic growth curves were constructed and adjusted to Count's model. Absolute (g/day) and relative (g kg-1 day-1) velocity curves were obtained from a derivative of this model. The growth curve was characterized by weight loss during the 1st week (4-6 days) ranging from 5.9 to 13.3 percent (the greater the percentage, the lower the birth weight), recovery of birth weight within 17 and 21 days, and increasingly higher rates of weight gain after the 3rd week. These rates were proportional to birth weight when expressed as g/day (the lowest and the highest birth weight neonates gained 15.9 and 30.1 g/day, respectively). However, if expressed as g kg-1 day-1, the rates were inversely proportional to birth weight (during the 3rd week, the lowest and the highest weight newborns gained 18.0 and 11.5 g kg-1 day-1, respectively). During the 12th week the rates were similar for all groups (7.5 to 10.2 g kg-1 day-1). The relative velocity accurately reflects weight gain of preterm infants who are appropriate for gestational age and, in the present study, it was inversely proportional to birth weight, with a peak during the 3rd week of life, and a homogeneous behavior during the 12th week for all weight groups