Factors influencing the reproduction and production performance of the Nguni cattle ecotypes in South Africa.

The objective of this experiment was to assess the reproductive and productive performance of Nguni cattle distributed among 11 farms in four regions of South Africa. Only data of registered Appendix A to Stud Proper Nguni animals from the Agricultural Research Council of South Africa’s database were used. Data were collected from 2061 dams and 3285 calves between 1990 and 2009.

Factors influencing reproductive performance of cows from different Nguni ecotypes in southern Mozambique.

The objective of this study was to assess the reproductive performance of two Nguni ecotypes (Nguni and Landim) raised in a subtropical environment to enhance strategies for livestock development and restocking programmes within the southern African region. Reproduction data collected between 1996 and 2009 from 365 cows of the Landim and Nguni ecotypes were analysed. From the results, ecotype, place of birth, year and season of birth/calving had significant effects on age at first calving (AFC) and calving interval (CI).

Influence of gonadotropins on insulin- and insulin-like growth factor-I (IGF-I)-induced steroid production by bovine granulosa cells.

To determine the effect of gonadotropins on insulin- and insulin-like growth factor (IGF-I)-induced bovine granulosa cell functions, granulosa cells from bovine ovarian follicles were cultured for 2 days in the presence of 10% fetal calf serum (FCS), and then cultured for an additional 2 days in serum-free medium with added hormones. In the presence of 0 or 1 ng/mL of insulin or IGF-I, FSH had little or no effect (P > 0.05) on estradiol production by granulosa cells from both small (1-5mm) and large (> or = 8mm) follicles.