Great Lakes Dairy Sheep Symposium - the Department of Animal ...

production doubles. However, there is not a big difference in the milk production of ewes with
different percentage of dairy genetics. In 1999 ewes with less than 50% dairy breeding produced
almost as much milk as ewes with 75% dairy breeding. In the following years, there was little or
no difference between 50%, 75% and more than 75% dairy breeding ewes. Yet almost each year
the milk production of each genotype kept increasing. In the early years, the overall production
of 1/2 East Friesian – 1/2 Dorset ewes was around 300-350 pounds but was near 700 pounds in
2004.
Perhaps the particular breed composition is more important to the overall production than
the percentage of dairy breeding. Figure 5 shows that for an equal dairy percentage of 75%, East
Friesian-Lacaune crossbred ewes produce more milk than the 75% East Friesian or the 75%
Lacaune. The percentage of EF-Lacaune crossbred ewes grew rapidly from 6.8% of the milking
flock in 2001 to 55.8% in 2004.
The average percentage of fat and protein in the milk (all genotypes, age of ewes and
type of management confounded), have also improved throughout the years (Figure 4). The
increase of the fat percentage is in part related to a higher proportion of Lacaune breeding. The
Lacaune breed is known for a higher fat content than the East Friesian.
Dairy “Value” of the Rams Used
It is possible to have an idea of the “value” of the rams used over time by comparing the
average production of their daughters. Figure 6 shows that none of the rams (not all rams are
shown) used at the Spooner Research Station are of outstanding value. The biggest difference
was between the two 50% EF rams used in 1994 and 1995 to start the dairy flock. All other rams,
East Friesian from Canada, New Zealand or of Dutch origin are all more or less equal. The same
hold true for Lacaune rams of Canadian (Switzerland) or of British origin. Therefore, the
increase in total milk production does not come from the use of better rams.
Length of the Milking Period
From 1996 to 2004, the average length of the milking period per ewe went from a little
over 100 days to 190 days as shown in Figure 7. The evolution curve of the length of the milking
period follows exactly the curve of the evolution of the total milk production. It looks like the
lengthening of the milking period is a very important, maybe the most important, contributor to
the increase of the total milk production. When, for some reasons, the average length of the
milking period was shortened in 2001, the total milk production was also decreased.
The lengthening of the milking period per ewe was achieved with 2 management
practices: 1. Lambing and milking earlier in the year: January instead of April. 2. Raising more
and more lambs on milk replacer and milking more ewes 24 hours after lambing.
Lambing Earlier in the Year
It seems that there is a strong correlation between the length of the milking period and the
photoperiod. Ewes lambing during short days have a longer lactation because more of their
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