BACKGROUND Selectively bred rodent lines are valuable tools for investigating gene × environment interactions related to risk for alcoholism in humans. Early maternal environment is one particular factor known for critically influencing neural, hormonal, and behavioral outcomes in adulthood. Cross-fostering is a procedure that may be used to explore the role of genotype-dependent maternal influ...

The number of lambs sold per ewe mated in the breeding flock has a considerable impact on sheep operation profitability. This depends primarily on fertility, prolificacy (# of lambs), and lamb survival, mothering ability, milk production of the ewe and lamb growth rate. Optimal reproduction does vary by environment and management system – some sheep operations don’t want a lambing rate over 200...

castration of male animal's leads to a reduction in aggressive behavior, which animals will avoid wasting energy resulting to economic production of the animal, grows. it also reduces damage and bruising animals and increases normed meat producing at slaughter. in this study, 20 lambs ghezel breed in four age groups, group 1: one month (n = 4), group 2: two months (n = 4) group 3: three months ...

Many investigators have called attention to the importance of heredity in breast cancer, lung tumors, leukemia, and other neoplasms of mice (cf. 1). Recently, the staff of the Roscoe B. Jackson Laboratory ( 2 ) has demonstrated the r61e of non-genetic factors and emphasized the need for a reinvestigation of the part played by heredity in the development of tumors.2 Experiments have been underta...