| Abstrakt: |
Predation losses reported by producers and claims by livestock industries that predation has severe impacts on the livestock trade are often cast in doubt. Here, the effects of predation on the reproduction and production of five Merino flocks and a Dorper flock, on a strictly monitored government entity (the Glen Agricultural Institute), from 1999 to 2007, are reported. These predation losses also cover other sheep losses from diseases, metabolic disorders, accidents, and livestock theft. Additional indirect financial losses, namely veterinary, shearing, supplementary feeding (lick), labour, and planted pasture costs, were calculated. The calculations were used to determine a more realistic cost of predation and to compare the extent to which financial losses ascribed to predation exceeded other losses. The Merino and Dorper flock numbers decreased significantly over the nine years covered in the study. Less reproductive ewes were available for mating and consequently resulting in less lambs that were born. The pre-weaned and post-weaned lambs were also severely impacted by predation. Due to predation, some ewes could not raise a single lamb in a six-year reproduction cycle. Therefore, it became challenging to replace older ewes and maintain flock sizes. An exception was the Merino flock that utilized ryegrass (Lolium multiflorum and L. perenne) because of protection from predation during critical phases in the reproduction cycle. Predation contributed 72% of annual financial losses, metabolic disorders, and accidents 20%, livestock theft 6%, and diseases 2%. Black-backed jackal (Lupullela mesomelas) alone accounted for 730 post-weaning losses, constituting 70% of all predation losses from 2003 to 2007. The negative effect of livestock predation made it impossible to evaluate the economic viability and sustainability of the four Merino treatment flocks as envisaged. A marked component of the genetic base of the two sheep breeds at the Glen Agricultural Institute (Glen AI) has also been lost permanently because of predation. [ABSTRACT FROM AUTHOR] |
