Last update: November 19, 2010 09:29:09 AM E-mail Print

 

Protein supplementation of late pregnant and lactating sheep and Angora goats

in the different grazing areas of SA

 

J.H. Hoon and M.J. Herselman

 

Grootfontein A.D.I., Private Bag X529, Middelburg (EC), 5900

Corresponding author: Jan Hoon

 


The aim of the project was to determine the effect of supplementation of late pregnant and lactating ewes with different protein sources on production and reproduction, in order to establish guidelines for day-to-day advice to producers.  The project was carried out at 16 localities (13 sheep and 3 Angora goats), representative of the different small stock grazing areas of South Africa. At each locality, a control (no supplementation) and two treatment groups (low and high bypass protein supplementation) were kept. The two supplementary diets were supplied at 300g/ewe/day for the last four weeks prior to lambing/kidding and 400g/ewe/day for the first eight weeks after lambing/kidding. The following data were recorded at all the localities: body weight of lambs/kids at 42-day age and at weaning, body weight of ewes at 42-day lamb/kid age and weaning percentage. An economic analysis was done on the pooled data of each locality, using the SM2004 model, to determine the economic viability of supplementation of ewes during late pregnancy and lactation. All the procedures were repeated for three/four consecutive years with the same nucleus of animals at each locality. The results in general indicated a positive response with supplementation of ewes during late pregnancy and lactation on body weight of ewes, growth rate of lambs and weaning percentages. It would, however, appear that the response was only substantial when grazing conditions were relatively poor, in quality and/or quantity. Furthermore, under less favourable grazing conditions, supplementation with a high bypass protein diet had a positive effect on the measured traits, specifically the weaning percentage. The results are supported by the economic analysis that indicated a positive response in gross margin/ewe with supplementation on sour grass veld, stubble lands and other poor quality pastures. Supplementation of ewes with a high bypass diet was also more profitable than a low bypass diet under less favourable grazing conditions.