The influence of environmental temperatures on farrowing rates and litter sizes in South African pig breeding units

Abstract

The reproductive performance of pigs is one of the main determinants of the profit farmers make from pig production. This study was undertaken to describe whether periods of high environmental temperature have an effect on the farrowing rate, litter sizes and number of stillbirths in commercial breeding units in South Africa. Data were collected weekly from four commercial breeding units with good records from December 2010 to August 2012. These data included the number of sows mated, number of sows farrowed and number of piglets born alive, as well as the number of stillbirths. Note was also taken of whether environmental temperature control mechanisms were employed. Temperature data from weather stations within 100 km of the breeding units were obtained from the South African Weather Service. In all breeding units a decrease in farrowing rate following mating during severe average temperatures (> 30 °C) when compared to the farrowing rate following mating during mild average temperatures ( 30 °C). Environmental temperature control did not negate this effect, but the breeding units employing the environmental temperature control did show higher average farrowing rates overall.

Keywords

• Seasonal infertility
• Litter size
• Farrowing rate
• Environmental temperature