The use of progesterone releasing intravaginal device (CIDR-B) with or without hCG for the induction of oestrus and ovulation in lactational anoestrus mares

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dc.contributor.advisorPhogat, J.B.
dc.contributor.authorAhlawat, Raj Kumar
dc.date.accessioned2017-08-19T04:43:56Z
dc.date.available2017-08-19T04:43:56Z
dc.date.issued2005
dc.description.abstractThe study was conducted on a total of 30 lactational anoestrus mares (10 mares each in Group A, B and C) during late breeding season (July/August) in the age group of 5–20 years and which have already foaled 1-10 times, located at Equine Breeding Stud, Hisar, Haryana. Easy breed CIDR device (containing 1.38 gm natural progesterone) was inserted intravaginally for a period of 12 days (day 0 to day 12) in mares of Group A and B, alongwith 0.450 mg PGF2 intramuscularly on the day of device removal. In one group (n = 7, Group B) of mares 3000 IU hCG intravenously was also administered on the day of natural covering/artificial insemination with fresh donkey semen and mares in Group C served as controls. The reproductive performance of these mares was recorded in terms of oestrus/ovulation induction response, conception and pregnancy rates. Plasma progesterone concentrations in 15 mares (6 mares of Group A, 5 mares of Group B and 4 mares of Group C) on days 0, 4, 8, 12, on the day of covering/A.I. and on day 12 post-covering of the treatment schedule were also monitored. During the treatment schedule five mares lost the CIDR-B device and these mares were excluded from the study, i.e. the CIDR-B device was retained by 15 out of 20 mares. An oestrus induction response of 86.66% was observed in treated mares of both the groups with a variable period of onset of oestrus following device removal. Majority of the mares i.e. 9 out of -ii- 13 (69.23%) exhibited signs of oestrus between 36-72 hours after CIDR-B removal, while three mares were induced to oestrus within 96 hours. Only one mare took 144 hours for onset of cyclicity after removal of the device. However, mean interval from removal of the device to onset of signs of oestrus was 68.30  8.94 hours. In control mares, out of 10 only three mares (30%) exhibited signs of oestrus during the experimental period which was significantly (p< 0.05) lower than treated mares. All mares from all the three groups in the present investigation, which exhibited signs of oestrus, also ovulated following covering/A.I. as confirmed by rectal palpation. The conception rate at the induced oestrus was very low (15.38%, 2/13) but 4 more mares conceived at the subsequent oestrus, thus, an overall conception rate of 46.15% was achieved in the mares treated with or without hCG. However, only one out of 10 mares conceived in Group C (controls) during the entire period of investigation. Plasma progesterone profiles in 7 mares (4 treated and 3 controls) indicated that these mares were already having luteal phase plasma progesterone concentrations (4-17 ng/ml) at the time of CIDR-B insertion (day 0), while in rest of the 8 mares plasma progesterone profiles were at basal levels at the time of CIDR-B insertion. In mares, which were having initial basal progesterone levels (1.64  0.19 ng/ml) on the day of device insertion, the levels significantly (p<0.01) increased to 5.64  0.89 ng/ml on day 4 following CIDR-B insertion and remained elevated (3.49  0.88) up to day 8. These values came down to 1.33  0.20 ng /ml (comparable to day 0) on the day of device removal (Day 12). Similarly in mares, which were having initial high progesterone profiles on the day of device insertion, progesterone concentrations increased in the same fashion as recorded in the mares having initial basal progesterone profiles at the time of device insertion. But on the day of covering/A.I. in all the mares (having initial basal or high progesterone concentrations) the plasma progesterone concentrations were either below the detection limit of the assay or below 1 ng/ml. which typically resembles to oestrus levels, clearly indicating and supporting our oestrus induction responseen_US
dc.identifier.urihttp://krishikosh.egranth.ac.in/handle/1/5810028996
dc.keywordsCIDR, PGF2a, HCG, Fertility, Mareen_US
dc.language.isoenen_US
dc.publisherLUVASen_US
dc.subAnimal Reproduction and Gynecologyen_US
dc.themeThe use of progesterone releasing intravaginal device (CIDR-B) with or without hCG for the induction of oestrus and ovulation in lactational anoestrus maresen_US
dc.these.typeM.V.Sc.
dc.titleThe use of progesterone releasing intravaginal device (CIDR-B) with or without hCG for the induction of oestrus and ovulation in lactational anoestrus maresen_US
dc.typeThesisen_US
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