Resumen

SANDOVAL, Espartaco ; VALLE, Alberto; JIMENEZ, Delia   y  MARQUEZ, Oswaldo. Birth weighs and growth evaluations of double purpose suckling calves with nursing cows during lactation period. Zootecnia Trop. [online]. 2005, vol.23, n.1, pp.1-16. ISSN 0798-7269.

Summary In order to evaluate the viability of using nursing cows for suckling calves, 177 crossbreed calves, born in an double purpose farm with tendency to the specialization in milk production, were monitored from their birth until three months of age. Data were analyzed by variance, including sex, birth season, and racial type of the calf, as well as their interactions, using the Tukey test for mean comparisons. Birth weight did not show statistically significant differences, although in the interaction season x racial type in the rain season, it corresponded to the smallest average for the animals predominantly Holstein, while in those with Zebu predominance it was higher (P<0.05). The daily weight gain for sex did not show statistically significant differences, with a tendency to decrease progressively as the age of the animal advances. There were statistically significant differences (P<0.05) among seasons (dry and rainy) for the first month of life, but it did not keep in the following months, showing an irregular behavior. Evidence of interactions genotype x environment and genotype x sex was detected. The wide variability in weight allowed inferring about the difficulty to standardize appropriate milk supply using nursing cows. It was observed a greater response of adaptation by Zebu predominant animals to environmental conditions and management system.

Palabras clave : Birth weighs; yearling calf; double purpose; nurses; weight gain..