Estimation of genetic parameters among reproductive and growth traits in yearling heifers

Growth and reproductive data were obtained on 779 beef heifers at the San Juan Basin Research Center, Hesperus, Co. Genetic parameters were estimated for age of puberty (AOP), age of first calving (AOC), julian day of first calving (DOC), julian day of second calving (DOSC), birth weight, weaning weight, yearling weight, and average daily gain from weaning to yearling and to cycling weights. The least squares model included birth year, age of dam and breed as fixed effects, sire/breed as a random variable, and day of birth and percent inbreeding as covariates. Day of birth was not included in the analyses of AOC, DOC or DOSC. Paternal half-sib estimates of heritability were: AOP, .10 +/- .17; AOC, .01 +/- .12; DOC, .09 +/- .13 and DOSC, .36 +/- .18. Genetic and phenotypic correlations were generally favorable, but genetic correlations were variable with large standard errors. Inbreeding had a detrimental effect on reproductive traits, and a seasonal effect was present for AOP.     

A comparative study on certain enzymes of the granulocyte from different ruminant species

In the present study the level of enzyme hydrolases (alkaline phosphatase, myeloperoxidase, elastase, arginase, lysozyme and β-galactosidase) of polymorphonuclear cell (PMN) granules in different ruminant species and their release in response to activation was studied. Buffalo PMN alkaline phosphatase activity was higher (P < 0.01) than in PMNs of cattle and goats. Interestingly, myeloperoxidase was higher in cattle PMNs and least in goat PMNs (P < 0.01), a similar pattern was observed in the distribution of enzyme arginase. As far as lysozyme is concerned, its activity was significantly higher (P < 0.01) in PMNs of buffaloes than in the case of cattle and goat PMNs. On activation, these cells released MPO and elastase, in all the species studied, while lysozyme was secreted only in buffalo PMN cells. Activity of certain enzymes related to oxidant defence systems such as glutathione peroxidase and glutathione reductase were higher in cattle and goats compared to that in buffaloes. These observations are likely to have bearing on immunodefense roles played by PMNs and reflected differences among the ruminant species studied.