Evaluating Breed Complementarity and Sexed Semen with Maternal Use of Afrikaner Germplasm

Abstract

Livestock production impacts food security of developing countries, especially where efficiency of production is compromised by environmental stressors. In South Africa, breeding with indigenous Afrikaner cattle that are genetically well adapted to subtropical environments is considered an essential strategy for sustainable beef production. Today, there is a potential for farmers to participate in commercial systems that join adapted Afrikaner germplasm, used in a specialized maternal role, with exotic terminal sires to optimize production. The objective of this study was to assess productivity of five simulated production systems: 1) straightbred Afrikaner mated naturally, 2) a straightbred Afrikaner cow herd with two sections; one section to produce replacement females and the other to cross with Charolais terminal sires, both using natural mating, 3) similar to 2, but applying sexed semen to produce replacement females, 4) similar to 2, but using a multi-breed composite dam line with a breed combination of 50% Afrikaner, 25% Hereford and 25% Simmental, and 5) similar to 4, but again applying sexed semen to produce replacement females. Parameter estimates needed to compare these systems were extracted from the scientific literature. Relative to straightbred Afrikaner dams, the simulated composite dams were more fit producing 7.8% more calves and their progeny performance was improved by reducing feed intake (−24.4%) and increasing meat production (+11.7%). The potential benefit of allocating more cows to the terminal sire was insufficient to offset the reduction in pregnancy rate that results with the use of sexed semen. Thus, system 4 had How to cite this paper: Khorshidi, R.,

Randomised controlled trial on estrus and conception impacts of reproductive and nutrition interventions on Kenyan smallholder dairy farms.

“…Reproductive efficiency on smallholder dairy farms (SDF) in low-income countries (LICs) is often low, as demonstrated by late sexual maturity of heifers and long calving intervals of cows (Centurión-castro et al, 2013). This situation is caused by many stressors such as heat and humidity (Khorshidi et al, 2017), diseases, parasites, poor nutrition and loss of body condition during lactation (Centurión-castro et al, 2013). Primary reproductive factors that extend calving intervals include a delay in the resumption of cycling in cows after calving, weak estrus expression, poor heat detection, poor semen quality, uterine infection, and poor timing of insemination (Kurykin, 2017).…”