Effects of synchronization and frequency in insemination on fertility.
Abstract: Fifty-four normally cycling, non-lactating mares were given 2 injections (i.m.) of PGF-2 alpha (10 mg) 14 days apart without regard to stage of the oestrous cycle. At 19 days after the first PGF-2 alpha treatment, a single i.m. injection of either hCG (3300 i.u.) or a GnRH-analogue (500 micrograms) was administered. Each mare was inseminated with 100 X 10(6) motile spermatozoa at one of the following frequencies: once only on Day 20; every other day during oestrus or at least on Days 19 and 21; or daily during oestrus or at least on Days 19, 20, 21 and 22. Eighteen control mares received saline injections on Days 0 and 14, and were inseminated either on the 4th day of oestrus or every other day or daily beginning on the 2nd day of oestrus. More (P greater than 0.05) PGF-2 alpha treated mares displayed their 1st day of oestrus on Days 14 to 20 than control mares (80.6 versus 27.8%). During cycle 1, fewer (P greater than 0.05) treated mares became pregnant compared to controls; 38.9, 25.0 and 66.7% for PGF-2 alpha + hCG, PGF-2 alpha + GnRH-A and control mares, respectively. After three cycles, the pregnancy rates for mares inseminated every other day or daily were higher (P less than 0.05) than mares inseminated only once during oestrus (88.9 and 88.2 versus 64.7%).
Publication Date: 1979-01-01 PubMed ID: 383985
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- Journal Article
Summary
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This study investigated the effects of synchronization and frequency of insemination on the fertility of mares. The findings suggest that mares inseminated every other day or daily exhibited higher pregnancy rates compared to those inseminated only once during their oestrus cycle.
Research Methodology
- Fifty-four normally cycling, non-lactating mares were involved in the study.
- These mares received two intramuscular (i.m.) injections of Prostaglandin F2 alpha (PGF-2 alpha), a compound used to control their oestrus cycle, 14 days apart.
- The stage of the oestrus cycle was not considered prior to these treatments.
- nineteen days after the first PGF-2 alpha treatment, the mares received one of two types of i.m. injections: human Chorionic Gonadotropin (hCG) or Gonadotropin-Releasing Hormone analogue (GnRH-A).
- Each mare was inseminated with a specific concentration of sperm on day 20 once, every other day during the oestrus cycle or daily during the oestrus cycle.
- As a control, eighteen mares received saline injections on Days 0 and 14 and were inseminated either on Day 4 of the oestrus cycle, or every other day, or daily starting from the second day of the oestrus cycle.
Key Findings
- More PGF-2 alpha treated mares displayed their 1st day of oestrus from Days 14 to 20 than control mares (80.6% versus 27.8%).
- During the first cycle, a smaller percentage of treated mares became pregnant compared to the control group; 38.9% for mares treated with PGF-2 alpha and hCG, 25.0% for those treated with PGF-2 alpha and GnRH-A, and 66.7% for control mares.
- By the end of the third cycle, mares inseminated either every other day or daily displayed higher pregnancy rates (88.9% and 88.2%, respectively) than those inseminated just once during their oestrus cycle (64.7%).
Implications
- The results suggest a potentially effective regime to increase fertility rates in mares which includes method of oestrus synchronization and frequency of insemination.
- Mares inseminated either every other day or daily during their oestrus cycle exhibited higher pregnancy rates than those inseminated just once.
Cite This Article
APA
Voss JL, Wallace RA, Squires EL, Pickett BW, Shideler RK.
(1979).
Effects of synchronization and frequency in insemination on fertility.
J Reprod Fertil Suppl(27), 257-261.
Publication
Researcher Affiliations
MeSH Terms
- Animals
- Chorionic Gonadotropin / pharmacology
- Diestrus / drug effects
- Estrus / drug effects
- Female
- Fertility / drug effects
- Gonadotropin-Releasing Hormone / pharmacology
- Horses / physiology
- Insemination, Artificial / veterinary
- Pregnancy
- Pregnancy, Animal / drug effects
- Prostaglandins F / pharmacology
- Time Factors
Citations
This article has been cited 1 times.- Bosu WT, Turner L. Changes in plasma progesterone concentrations in mares treated with cloprostenol and human chorionic gonadotropin and inseminated during estrus. Can Vet J 1983 Aug;24(8):253-7.
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