Vie CONG. INTERN. REPROD. ANIM. INSEM. ARTIF., PARIS, 1968, VOL. I

Table 1. O 0 0, d esponge dat
Group No. of No, of sows on No., of sows farrowing to
sows oestrus during lactational mating
lactation
1 6 0 0
2 5 1 1
3 6 2 2
4 7 5 4

Stage 2, The success of the treatment applied to Group 4 was
evaluated using larger numbers of animals. The oestrous res-
ponse and pregnancy response data are shown in Table 2,

Table 2. Oestrous response and pregnancy response data e
Group No., of No. of sows on No. of sows farrowing to
sows oestrus during lactational mating
lactation
1 11 0 0
4 18 16 11

In those sows in Group 4 showing oestrus during lactation,
the mean interval from PMSG injection to oestrus was 4.2 days.
In those sows in Group 4 which farrowed as a result of mating
during lactation, the mean interval between the birth of suc-
cessive litters was 143.8 days compared with 169.6 days for
control sows. The mean number of young born as a result of
lactational matings in Group 4 was 9.7 compared with 10.5 for
control sows mated at the post-weaning oestrus. The mean growth
rate to weaning of the young of concurrently pregnant and lac-
tating sows in Group 4 was normal when compared with controls.

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(7) W.M.PALMER, H.S.TEAGUE & W.G.VENZKE, 1965. J.Anim.Sci.
2L35/1-545.

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(11) D.B.CRIGHTON, 1961. M.Sc. thesis, University of Edinburgh.
(12) This work was supported by a grant from the Pig Industry
Development Authority. The PMSG used was a gift from

Burroughs Wellcome and Co,

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