Effect of Light, Temperature, and Hormones on the Reproductive Performance of Ewes2

Wilson, R. L.; Godley, W. C.; Hurst, Victor

doi:10.2527/jas1961.204693x

Cited by 7 publications

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“…have generally been poor. Wilson, Godley & Hurst (1961) also found the conception percentage after A.I. in progesterone-p.M.s.…”

Section: Practical Implicationsmentioning

confidence: 82%

The induction of pregnancy in the anoestrous ewe by hormonal therapy V. Progesterone-pregnant mare's serum therapy on Clun forest maiden sheep and general conclusions

Gordon

1963

J. Agric. Sci.

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In a previous paper (Gordon, 19586) results were given on the application of progesterone-p.M.s. therapy in out-of-season breeding which showed that non-lactating ewes conceived more readily than lactating animals. In the trials with ' dry' sheep the most promising results, in terms of conception percentage, were noted in maiden yearling ewes. While results given earlier in this series (Parts II and III) suggest that a solution to the problem of out-ofsoason breeding, especially in lactating ewes, may lie in the use of repeated progesterone-p.M.s. therapy, there is some doubt whether such extended therapy is justifiable in applications to yearling (maiden) animals. Obviously, if there is strong evidence that a satisfactory practical result follows standard (single course) treatment, such information would be useful to the flock-owner. Trial 1The present work was to provide further information on the response of the maiden ewe, and to establish some of the reasons why this category of animal usually shows a better conception percentage than either mature 'dry' or lactating ewes. The work was restricted to animals of the Clun Forest breed, this being an obvious choice of sheep which flock-owners would use in out-of-season breeding. MATERIAL AND METHODSSheep. Experiments were undertaken in two flocks of Clun maiden ewes, made available by two co-operating farmers in Hampshire in 1958. A total of seventy-six was involved (flock 45, forty-seven ewes; flock 46, twenty-nine ewes), the sheep being approximately 1 year old and not previously exposed to the ram. Ten Clun rams were used in the matings (five per flock).Hormones and method of administration. Progesterone was used as an oil solution, 1 ml. containing 10 mg.; the solution was given intramuscularly.A freeze-dried preparation of P.M.S. was subcutaneously injected in all treatments.Treatment and field procedure. Treatment consisted of three doses of 50 mg. progesterone administered at intervals of 3 days; 750 i.u. of P.M.S. was given 2 days after the final progesterone injection. Injections commenced 29 March in flock 45 and 3 April in flock 46. In each instance, treatment was applied simultaneously to all animals.In flock 45, the first part of the experiment consisted of observations on the incidence of spontaneous oestrus in the Clun yearling ewe during the latter part of the normal breeding season. Two rams were 'raddled' and introduced among the fortyseven ewes on 10 February. Daily inspection for matings was made for a 47-day period which ended 29 March, the time at which hormone treatment commenced.The full complement of rams joined each flock following administration of P.M.S. All rams were ' raddled' and a daily record of matings maintained for a period of 2 weeks after the end of hormone treatment. Sheep were identified by plastic eartags, and prominently marked on the fleece for easy field recognition. The sheep on each farm were kept together in the one group for the period of pregnancy. They were on grass for the period of the experiment; no suppleme...

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“…have generally been poor. Wilson, Godley & Hurst (1961) also found the conception percentage after A.I. in progesterone-p.M.s.…”

Section: Practical Implicationsmentioning

confidence: 82%

The induction of pregnancy in the anoestrous ewe by hormonal therapy V. Progesterone-pregnant mare's serum therapy on Clun forest maiden sheep and general conclusions

Gordon

1963

J. Agric. Sci.

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“…(Received 20th August 1973) It has been established that reproductive performance of ewes during the breeding period is adversely affected by constant high ambient temperatures of 32 to 35\s=deg\C (Alliston & Ulberg, 1957, 1961Dutt, Ellington & Carlton, 1959;Dutt, 1963) and favourably affected by constant low ambient temperatures of 16 to 21\s=deg\C (Alliston & Ulberg, 1957;Wilson, Godley & Hurst, 1961;Godley, Wilson & Hurst, 1966). In commercial practice, however, ewes are subjected to prevailing diurnal atmospheric conditions.…”

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confidence: 99%

Effect of Temperature Under Field Conditions on the Reproductive Performance of Ewes

Neville¹,

Neathery²

1974

Reproduction

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Influence of nutrition on reproduction in the ewe with special emphasis on progesterone concentration

et al. 1975

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Effect of Light, Temperature, and Hormones on the Reproductive Performance of Ewes2

Cited by 7 publications

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The induction of pregnancy in the anoestrous ewe by hormonal therapy V. Progesterone-pregnant mare's serum therapy on Clun forest maiden sheep and general conclusions

The induction of pregnancy in the anoestrous ewe by hormonal therapy V. Progesterone-pregnant mare's serum therapy on Clun forest maiden sheep and general conclusions

Effect of Temperature Under Field Conditions on the Reproductive Performance of Ewes

Influence of nutrition on reproduction in the ewe with special emphasis on progesterone concentration

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