Sheep - AgRIS

Genetie Sex of First stage Second stage Third stage
groups the lamb Mean±SE Mean±SE Mean±SE
Nali M 343.5±19.50 33.6±2.14 154.9±8.40
24 27 29
F 396.0±14.37 33.8±2.04 135.5±14.69
15 30 30
Both sexes 367.7±17.51 33.7±2.09 145.1±11.60
Lohi M 259.0±38.07 33.1±1.61 131.7±16.16
10 14 14
F 4213±28.41 32.3±1.81 131.6±7.11
9 13 12
Both sexes 288.5±33.25 32.8±1.73 131.6±10.50
19 27 26
Nellore x Nali M 327.8±29.11 33.8±0.80 161.4±13.17
7 7 7
F 330.6±18.72 33.8±0.88 135.5±13.19
8 10 10
Both sexes 329.3±24.41 33.8±0.88 146.1±13.8
15 17 17
Mandia x Nali M 459.4±96.69 37.8±2.89 124.0±12.40
9 9 8
F 468.6±74.44 41.8±5.81 113.7±17.25
5 5 4
Both sexes 462.7±83.65 39.3±4.32 120.6±14.92
14 14 12
Relationship among weight of placenta, number of cotyledons and birth weight has been
studied by Kaushish and Arora (1983). The average number of cotyledons varied form 66.6 to
74.1 between groups. The weight of placenta ranged from 0.195 to 0.259 kg. The sex of the
lamb did not affect the placental weight and the number of cotyledons significantly. There was
a positive relationship between placental weight, number of cotyledons and birth weight
(Kaushish, 1971). Weight of placenta as percentage of lamb weight generally centered round
about 8.5 percent in Nali, Lohi and the crosses of former with Mandia and Nellore (Kaushish
and Arora, 1975). It was little lower in Bikaneri and Mandia (Tiwari et al., 1969a). The effect
of weight at service on time taken for expulsion of foetus and placenta has been studied by
Kaushish and Arora (1973).
Post partum estrous
Most ewes are seasonal breeders, consequently there are few attempts for the ovaries to
function until the breeding season occurs for that particular breed. In the breeds which have
been selected to produce two crops of lambs each year, there is need for breeding soon after
lactation ceases. As soon as weaning occurs, these brees usually show a cyclic activity in the
ovries accompanied by estrous and ovulation Table 7.4.
Table 7.4 Duration of different stages noted in the process of parturition
Single births Abortions
Interval(days) % of ewes Mean±S.E. % of ewes Mean±S.E.
> 60 19.1 35.5±1.94 14.0 35.5±6.20
61-90 16.1 77.6±1.18 5.3 77.0±1.0
91-120 12.3 103.9±1.27 7.0 101.0±3.10
121-150 12.3 137.1±1.28 7.0 135.0±4.77
151-180 12.9 163.8±1.38 28.1 167.4±1.90
181-210 9.1 196.0±1.60 17.5 194.8±2.95
211-240 7.1 229.5±2.14 1.8 240.0±0.00
241-270 2.3 254.1±2.70 7.0 249.8±3.11
271-300 3.9 285.2±2.20 5.3 272.7±1.53
301-and above 4.5 353.5±7.03 7.0 426.7±47.06
Induction of parturition
Hormones like dexamethasone or flumethasone (Bosc, 1972) can be used to induce
lambing in sheep. Hormones have been used to combat prolonged pregnancy of Karakul ewes
in South Africa (Roux and Wyk, 1977). The interval between injection and partiurition depends
on the stage of pregnancy (Aswad et al., 1974) and if the ewes are injected too early, the lambs
die (Webster and Haresign, 1981). There is a great scope for this in tropics.
417