A survey of reproductive success in South African Thoroughbred horse breeding from 1975 to 1999.

This research paper presents an analysis of the reproductive success rate of Thoroughbred horses in South Africa during a 25-year period from 1975 to 1999, showing improvements in live foal production and reductions in barren mares and twins, linked to advances in veterinary healthcare.

Background and Scope

• This study is based on the statistical data taken from the ‘Return of Mares’ of the General Stud Book of The Jockey Club of Southern Africa spanning a quarter century from 1975 to 1999.
• It reflects detailed analysis of the data related to various aspects of Thoroughbred horse breeding in South Africa over this period.
• These aspects include the total number of mares covered per season; the total numbers and percentage of their living produce; the total numbers and percentage of dead produce, ‘slips’ and foals born dead; barren and ‘no return’ mares; and the total number of live twins reported.

Key Findings

• There was a significant increase in the percentage of live foals per season from 52% to 62% over the period surveyed, showing improvements in reproductive success.
• The percentage of barren and ‘no return’ mares (mares that didn’t conceive) declined notably from 35.5% to 28.4% over the period, indicating improvements in breeding practices.
• The number of live twins reported showed a dramatic reduction from 156 to 5, which can be seen as a beneficial trend given the risks associated with twin pregnancies in horses.
• These observed improvements are attributed to a combination of factors, including advances in veterinary knowledge and technology.

Comparative Analysis and Future Research

• The findings of this research were compared to those reported by similar surveys of Thoroughbred horse populations in North America and Germany, indicating a similar trend.
• The paper also suggests the need to expand the scope of this annual survey by recording additional parameters such as pregnancy and live birth rates, that more accurately reflect reproductive efficiency rather than just a cumulative annual total of live foals.