Sheep - AgRIS

Mortality in young lambs and other stock
As a guideline, the following mortality figures should not be allowed to exceed under the
ideal sheep management practices:
Birth to weaning - 5-10%
Weaning to 6 months - 5-8%
6 months to 1 year - 3-5%
1 year and above - 0-5%
9.2.7 TeaserRams
The number of vasectomised rams used is 1% of the original number of ewes i.e. 5,000
ewes 50 teasers and even when there are only 1,000 ewes left in the mob 50 teasers should still
be used. All vasectomised rams are tested for brucelosis. Two teams of teasers are used and
alternated every 3rd day. The time to change teasers is when a large percentage ofthe ewes that
are presented for insemination have creamy vaginal mucus. This indicates that estrous has
terminated and this means that teasers did not detect estrous at the onset, either because there
were too many ewes or they had lost interest.
9. 2. 8 Breeding Rams
Rams, should have access to pasture or irrigated plots and be fore they are let out on
pasture, should be inspected daily for fly strike, screw worm and foot abscess. Rams at two
tooth stage are separated from adults to prevent fighting and homosexuality.
When the actual insemination programme starts, the rams are still housed and fed as before
and walked to the shearing shed and back daily, to ensure exercise. When in use at the shearing
shed and back daily, to ensure exercise. When in use at the shearing shed, they are penned
separately awaiting their turn as semen donors to avoid fighting with other males and to save
time in handling.
The training, actually does not begin till the programme starts and it seldom takes more
than two days to get all rams to serve an ewe and subsequently into an A.V. The number of
collections to be obtained in a day varies from ram to ram. From most of the rams semen can be
collected three times a day producing average ejaculates of 1.0 ml, sperm concentration of 35 x
108 per ml and live counts 85-90% (Miller, 1975). He further reported 15,000 x 106 sperm per
day from two teeth rams in three collections (Table 9.1).
Table 9.1 Results of rams semen examined on day 6th and 15th day of semen collected
Vol.(ml.) Sperm No. x 10 8 Live (%)
No. I No.2 No 3 No.1 No.2 No.3 No. l No.2 No.3
Day-6
Ram A 0.7 1.4 0.8 39 45 45 90 92 88
Ram B 1.0 1.0 1.1 41 31 31 90 S6 88
Ram C 0.8 0.6 0.5 34 45 45 82 95 95
Ram D 0.7 1.0 0.4 54 43 36 95 95 95
Day-15
Ram A 0.6 1.0 0.8 40 40 35 90 90 90
Ram B 1.0 1.0 1.0 40 35 30 90 S5 90
Ram C 0.0 0.6 0.4 32 40 45 80 90 95
Ram D 0.7 0.5 0.7 45 40 35 95 95 90
Semen could successively be collected upt to 5 times daily for 17 days from mature rams
without fall in semen quality (Miller, 1975).
9. 2. 9 Management of Ewes
Keast and Morley (1949) and Dun et al. (1960) recommended overnight teasing and
drafting raddled ewes offin the morning. This is quite manageable for small lots, but when large
numbers have to be inseminated it takes lot of time as ewes connto be presented for A.I. at
proper time during estrous. Under the circumstances the rams have to be worked too frequently
to provide necessary semen. When large number of ewes are to be handled, harnessed
vasectomised rams are released with the ewes at about 5 p.m. and the mob turned into a
paddock. They are mustered into the yards by 8.00 a.m. the following morning and marked
ewes drafted off. With few modifications to most sheep yards, this can be done at the rate of
4,000 per hour.
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