ABSTRACT Dairy sheep production research was initiated at the University of Wisconsin-Madison in 1993. Studies have been conducted on performance of East Friesian (EF) dairy sheep, weaning systems, and supplementation of the diet with rumen bypass fat. Lambs and ewes of 12.5 to 50% EF breeding were compared to lambs and ewes of 0% EF and 75 to 87.5% Dorset breeding from 1993 through 1997. East Friesian-cross lambs had greater (P < 0.05) birth, weaning, and postweaning weights than Dorset-cross lambs. When lambing at 1 and 2 yr of age, EF-cross ewes gave birth to and reared more (P < 0.05) lambs per ewe mated, had more (P < 0.05) days in lactation, and produced 1.9 times more (P < 0.05) milk and more weight of milk fat and milk protein than Dorset-cross ewes. In 1999 and 2000, lambs of over 50% EF breeding had lower (P < 0.05) survival rates than lambs of less than 50% EF breeding due to greater susceptibility to respiratory disease. Lambs of 0% EF breeding had survival rates similar to all EF-cross groups of is less than or equal to 50% EF breeding. Raising lambs on milk replacer and starting the milking of ewes 24 to 36 h after parturition resulted in a 61% increase (P < 0.05) in milk production compared to starting the milking period after lambs were weaned at 30 d of age. A system of leaving lambs with the ewe for half the day and milking the ewe once per day during the first 30 d after parturition followed by twice-daily milking was the most profitable system because ewes raised their lambs and still produced 85% as much milk as did ewes milked twice per day from shortly after lambing. However, milk obtained from ewes nursing their lambs had a lower (P < 0.05) fat percentage than milk from ewes that had weaned their lambs. Feeding supplemental fat increased (P < 0.05) milk fat percentage of ewes that had weaned their lambs but not of ewes that were still suckling their lambs. Large increases in average ewe milk yield in U.S. milking sheep flocks are possible within a few years. Average milk yield per ewe in our research flock increased from 76.9 kg for 130 ewes in 1996 to 223.5 kg for 267 ewes in 2000. Whereas a significant proportion of this increase in milk yield was a result of an increase in ewe age, the majority of the increase in milk yield was attributed to increased proportions of East Friesian breeding in the ewe flock and initiation of milking shortly after parturition.
Implications
Milk yield of dairy sheep can be almost doubled if ewes of 25 to 50% East Friesian (EF) breeding are used. Milking EF-cross ewes once or twice a day during the first 30 d postpartum rather than waiting to start milking until after lambs are weaned at 30 d of age will result in a further 61 and 38%, respectively, increase in milk yield. Ewes that are milked once a day during the first 30 d postpartum also rear their lambs, resulting in a profitable system. However, a disadvantage of this system is the low fat percentage of the milk obtained during the suckling period, and feeding supplemental fat does not raise milk fat percentage. Large increases in flock milk yield are possible in a few years. Average milk yield per ewe in the Spooner flock went from 76.9 kg for 130 ewes in 1996 to 223.5 kg for 267 ewes in 2000. The majority of the increased milk yield was due to increased proportions of East Friesian breeding in the ewes and initiation of milking shortly after parturition.
Key Words: Dairy Research, East Friesian (Sheep Breed), Milk, Sheep
© 2001, by the American Society of Animal Science. All rights reserved.
J. Anim. Sci. 2001. 79:E16-E20
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