Effect of Early Weaning and Hormone Treatments on Induction of Estrus, Conception and Lambing of Fall-Lambing Karakul Ewes2

Sefidbakht, N.; Farid, A.

doi:10.2527/jas1977.452311x

Cited by 8 publications

(3 citation statements)

References 15 publications

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“…Others have reported no such effect (e.g. Whiteman, Zollinger, Thrift & Gould, 1972;Sefidbakht & Farid, 1977). These differences may be due to the influences of species or breed, locality or season.…”

Section: Maximizing Reproductionmentioning

confidence: 95%

“…Some workers have reported shorter periods of anoestrus and a higher percentage of females coming into oestrus during a specified period after birth for females whose lambs have been weaned early (0-3 days) compared to later weaning (30+ days; e.g. Mallampati, Pope & Casida, 1971;Sefidbakht, Makarechian & Ghorban, 1971;Gould & Whiteman, 1973;Restall & Starr, 1977;Lawson, Forrest & Shelton, 1984), although the anoestrous period is usually shortened by only a few days. Others have reported no such effect (e.g.…”

Section: Maximizing Reproductionmentioning

confidence: 99%

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Reproductive biology of Nilgiri tahr, Hemitragus hylocrius (Mammalia: Bovidae)

Rice

1988

Journal of Zoology

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The reproductive biology of Nilgiri tahr (Hemitragus hylocrius) was studied in Eravikulam National Park, Kerala, India from August 1979 to September 1981. The rutting season occurred during the monsoon (July and August) and the main birth season was January to mid‐February. Gestation was estimated at 179 days. Three females which lost their first young in 1981 conceived 18 to 21 days post‐partum. One female conceived of her second young while the first was 15 days old. The remainder of the individually identified females gave birth to one young (n=40) or none (n=4). Infant mortality was highest during the first two weeks after birth. Young born during the monsoon also had a high mortality rate (0.50/week). Oestrus during the rut was discontinuous in 1980 and 1981. Periods of frequent oestrus corresponded with periods of low rainfall with a mean lag time of 4.9 days. The ultimate factor determining the birth season in Nilgiri tahr appears to be weather. The main birth season is timed so as to minimize thermal stress. Several proximal factors may be important in stimulating reproductive activity. These include photoperiod, temperature, the presence of males in mixed groups, and nutrition. The photoperiod response is unusual in that Nilgiri thar evidently respond to the abrupt decrease in apparent day length associated with the onset of the monsoon. The inverse correlation of rainfall and oestrous activity may have been effected through the sudden decrease in thermal stress on the females or heavy rainfall (5.7 cm/day) masking pheromonal stimulation. The pattern of lactation anoestrus observed in Nilgiri tahr approximates results obtained from some studies of domestic Caprini. Nilgiri tahr females are presumably able to increase their lifetime reproduction by giving birth twice in one year. However, this strategy seemed counterproductive in 1981 as survival was low for second offspring.

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Section: Maximizing Reproductionmentioning

confidence: 95%

Section: Maximizing Reproductionmentioning

confidence: 99%

Reproductive biology of Nilgiri tahr, Hemitragus hylocrius (Mammalia: Bovidae)

Rice

1988

Journal of Zoology

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“…Research conducted with sheep on the effect of early weaning on the stimulation of early postpartum oestrus also gave conflicting results. Some researchers reported that lactation delays the onset of postpartum behavioural oestrus while others found no significant differences between early and late weaned ewes (Sefidbakht and Farid, 1977). However, Stagg et al (1998) studied the effect of calf isolation on follicular wave and hormone changes, and clearly demonstrated that the suckling effect in beef cows was the major factor affecting the duration of the postpartum on oestrous interval.…”

Section: Hormonesmentioning

confidence: 99%

The Influence of Weaning Time on Deer Performance

Bao¹,

Ru²,

Glatz³

et al. 2004

Asian Australas. J. Anim. Sci

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Current growth in the deer industry is 20% per annum as the demand increases for venison in Europe, including the increased use in Asia of antlers as a natural medicine by humans. The deer industry in Australia has developed rapidly, but farm profitability has fluctuated markedly. The knowledge on deer farming has largely been adopted from New Zealand (NZ) and the United Kingdom (UK) although the environmental conditions in these deer growing countries differ markedly from Australia. The practice used for weaning is one of the key factors influencing the profitability of the industry. However, a wide range in weaning dates are practised by farmers leading to the question of whether deer should be weaned after mating to reduce the stress during weaning or should they be weaned in the pre-rut period to allow does to recover their body condition for the next reproduction cycle. This review examines the effect of weaning time on the performance of does and hinds and the subsequent growth rate of the fawns and calves. Gaps in knowledge of weaning procedures and nutritional management for early weaned deer are identified.

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