Last update: November 19, 2010 11:50:58 AM E-mail Print

 

Milk production of grazing wool sheep ewes

 

M.A. Snyman1, M.J. Herselman1, S.W.P. Cloete2, P.J. Griessel1, M. van Heerden1, T. Buys3 and A.C. Greyling4

 

1Grootfontein ADI, P/Bag X529, Middelburg (EC), 5900

2Institute for Animal Production, P/Bag X1, Elsenburg, 8500

3Carnarvon Experimental Station, P.O. Box 98, Carnarvon, 8995

4Cradock Experimental Station, P.O. Box 284, Cradock, 8888

Corresponding author:  Gretha Snyman

 


The aim of this study is to evaluate the use of maternal breeding values for early growth traits as alternative or additional selection criterion for improved growth efficiency in slaughter lamb production enterprises. As the objective of the study is to determine milk production of all ewes in the experimental flocks for the next 10 years, the most accurate time for recording of milk production should be determined. In the first part of the study, milk production and the average shape of the lactation curves for the ewes in each of the experimental flocks were determined. During 2004, ewes in the Carnarvon Afrino flock, as well as the Grootfontein Dohne Merino flock, were milked. During 2005, ewes in the Elsenburg Merino flock and Cradock fine wool Merino flock, were milked. Milk production of the ewes was determined at 7, 14, 21, 28, 35, 49, 63, 77 and 98 days after lambing, and at weaning, through the oxytocin technique. Milk samples were collected from ewes in the Afrino and Dohne Merino flocks at each milking for determination of milk fat, milk protein and lactose. Daily milk production (DMP) for the weeks when actual milk production was not recorded was obtained by interpolation. Dohne ewes produced more milk per day than the Afrino ewes (1260±162 vs. 912±146 ml/day), indicative of the better grazing conditions at Grootfontein during the recording period. Total weekly milk production was used to obtain lactation curves. There were large differences in the shape of the lactation curves of individual ewes. Milk production during Week 3 and Week 12 together accounted for 76% of the variation in total milk production. Therefore, for the purpose of predicting total milk production, the milk production during the third and twelfth weeks of lactation will be recorded for all the ewes in the experimental flocks in future.