Approaches to improve the ovulatory response and reproductive performance of ewes introduced to rams during seasonal anestrus

Jordan, Katherine M.

doi:10.33915/etd.2202

Cited by 2 publications

(5 citation statements)

References 61 publications

(110 reference statements)

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“…Probably, sheep detect day light changes by means of a bult-in biologic clock in the hypothalamus, and this information is transmitted to the hypothalamus gonadal axis via the pineal gland (Bowen, 2003). Melatonin, a pineal hormone, mediates the response to changes in the photoperiod in sheep (Bowen, 2003), melatonin levels are high during dark period and low during light period, probably these differences in the pattern of melatonin secretion act as a signal indicating day length to the nevroendocrine axis (Jordan, 2005), melatonin which is produced and secreted by the pineal gland exclusively at night, is believed to determine the effects of photoperiod on the cyclic activity of the ewe, along duration of melatonin secretion signals a short-day, where as a short duration of melatonin secretion signals a long day ( Younes, 2008).…”

Section: I11 Seasonality and Ovarian Activitymentioning

confidence: 99%

“…As in other species the estrus cycle can be divided into phases. the follicular phase 3-4 days, and the luteal phase that lasts about 14-15 days, which characterized by the maturation of the corpus luteum and high levels of progesterone that reach a maximum peak about 6 days after ovulation (Jordan, 2005).…”

Section: I12 the Estrus Cyclementioning

confidence: 99%

“…Melatonin, which called the darkness hormone, secreted from pineal gland, secretion increase when the day length becomes shorter, which effect on hypothalamus and secretion of the gonadotropin hormone, However, can be using exogenous melatonin as mimic effect to shorting day lengthy, therefore, used widely to improve performance of reproductive during anestrus (Jordan, 2005). Waller et al, (1988) found that the ewes treated orally with 2mg melatonin daily in anestrus season, have more estrus cycles than control ewes and similar to ewe treated with progesterone, and PMSG.…”

Section: I34 Melatoninmentioning

confidence: 99%

“…The ram effect allows induction breeding during anestrus and produce some of synchrony of cycle among the ewes in flock (Chanvallon et al, 2008). However, this common practice to isolate the ewes from rams (including sight, sound, and smell) for a period of time before introduction to get reproductive response (Jordan, 2005).…”

Section: I31 Introduction Of Ramsmentioning

confidence: 99%

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Different estrous induction protocols during non-breeding season in Assaf ewes

Mahmoud

Abu²,

Gazal³

2018

Sci. J. Vet. Adv.

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This experiment was conducted to investigate the effect of pregnant mare serum gonadotrophin (PMSG) levels (300 or 600 I.U.) and the progestagen method (one sponge for 14 d or two sponge each for 7 d) on estrus response, onset and duration of estrus,lambing rate, litter size and serum progestagen concentrations during estrus period and early pregnancy. Atotal of 20 assaf ewes were used in the experiment which was conducted during April, a month that is considered as non-breading period in Palestine. Ewes were inserted with intravaginal sponges that containing 60 mg Medroxyprogesterone acetate (MAP). Seven days later, these sponge were removed and 10 new sponges were inseted to 10 of the experimental ewes. Following withdrawal of sponges, at day 14, 5ewes from each tretmant groups were injected intramauscularly with PMSG at level of 300 and 600 IU. This investigation showed that level of PMSG and progesterone application methods had no significant effects on the tested parameters, also, there are significant different in progesterone concentration between ewes gave brith to single and twines. This finding indicated that low level of PMSG can be XIII applied for estrus synchronization where lots of savings can be achieved for the benefit of local sheep farmers. Although, some slight differences were obtained but there was no significant differences between the two different progesterone application methods nor the two different PMSG doses. So one sponge followed by 300I.U. PMSG can be used to synchronize estrus successfully and with lower cost than using two sponges or high PMSG doses.

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Section: I11 Seasonality and Ovarian Activitymentioning

confidence: 99%

Section: I12 the Estrus Cyclementioning

confidence: 99%

Section: I34 Melatoninmentioning

confidence: 99%

Section: I31 Introduction Of Ramsmentioning

confidence: 99%

See 2 more Smart Citations

Different estrous induction protocols during non-breeding season in Assaf ewes

Mahmoud

Abu²,

Gazal³

2018

Sci. J. Vet. Adv.

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“…Ram leads to a rise of the LH concentration in females within a few minutes and later to an increased LH pulse frequency, which is a prerequisite for this method can improve the efficacy of estrus synchronization or induction as well. In this respect, Jordan (2005) reported that introduction of rams to ewes induced ovulation, and this method is referred to as the ram or male effect. This effect allows induction breeding during anestrus and produce some of synchrony of cycle among the ewes in flock (Chanvallon et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Estrus Synchronization in Ewes Using Sponges With PMSG or Ram Effect With or Without Progesterone Injection

Abdel-Khalek

Khalil

El-Saidy³

et al. 2014

Journal of Animal and Poultry Production

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Total of 40 crossbred ewes were divided into five treatment groups (8 ewes each). Ewes in the first group (G1) represented the control ewes which were allowed for natural mating. The control ewes were exposed to fertile ram from the contemporary to that of treatment groups start time up to the end of the breeding season (end of September) and natural mating was applied for those coming in estrus. Ewe in the other four treatment groups G2, G3, G4 and G5 treatment groups were inserted with 20 mg sponges for 11 days, and ewes in G2 were injected with 300 IU PMSG on the Day 11 (sponge withdrawal), ewes in G3 the same treatment of G2 but injected with 1 ml progesterone (Lutone) before the sponge withdrawal with 24 h (Day 10), ewes in G4 after sponge withdrawal teaser introduce ram kept until artificial insemination was done. Ewes in G5 the same treatment of G4 but injected with 1 ml progesterone (Lutone) before the sponge withdrawal with 24 h (Day 10). Ewes in all treatment groups were artificially inseminated twice 48 and 56 hr after the sponge removed with fresh diluted semen. Blood samples were taken during treatment period for P4 assay.Results show that estrus rate was 100% in treatment groups and onset of estrus was the latest (P<0.05) with the longest duration (P<0.05) in ewes of G5, while those in G2 showed an opposite trend. Lambing rate was the highest (P<0.05) in G2 and G5 (75%), moderate in G3 and G4 (62.5%) and the lowest in G1 (50%). Ewes in G3 showed the highest (P<0.05) fecundity and twining rates (112.5% and 1.80 lamb /ewe) due to the greatest number of twins as compared to other treatment and control groups. The differences in average LBW of lambs at birth between all treatment groups and the control one were not significant. There was marked differences in P4 level according to treatment and lambing in different groups. In conclusion, the findings of the present research indicate that primary P4 and PMSG is a beneficial adjunct to the breeding of sheep by AI at progestagens-synchronized estrus and administration of 300 IU PMSG at sponge withdrawal is more effective for increasing the reproductive performance of artificially inseminated crossbred ewes in breeding season.

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Approaches to improve the ovulatory response and reproductive performance of ewes introduced to rams during seasonal anestrus

Abstract: Thesis submitted to the Davis College of Agriculture, Forestry, and Consumer Sciences at West Virginia University in partial fulfillment of the requirements for the degree of Master of Science in Reproductive Physiology

Cited by 2 publications

References 61 publications

Different estrous induction protocols during non-breeding season in Assaf ewes

Different estrous induction protocols during non-breeding season in Assaf ewes

Estrus Synchronization in Ewes Using Sponges With PMSG or Ram Effect With or Without Progesterone Injection

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