Document Detail

Short-term treatment with a controlled internal drug releasing (CIDR) device and FSH to induce fertile estrus and increase prolificacy in anestrous ewes.
MedLine Citation:
PMID:  11322244     Owner:  NLM     Status:  MEDLINE    
The objectives were to evaluate, in anestrous ewes, the effectiveness of a CIDR-G device (0.3 g progesterone) administered for 5 d to induce estrus; and FSH (Folltropin; 55 mg NIH-FSH-P1 equivalent) in saline:propylene glycol (1:4) 24 h before insert removal (Day 0), to increase ovulation rate and prolificacy. Ewes of mixed breeding were assigned at random to 3 treatments: control (C; n = 125), 5 d progesterone (P5; n = 257) and 5 d progesterone plus FSH (P5F; n = 271). Intact rams were joined at insert removal and ewes were observed every 24 h for 3 d. On Day 14, the ovulation rates of all ewes detected in estrus in the treated groups were determined using transrectal ultrasonography. Rams were removed on Day 26 to 31. Ewes were examined for pregnancy then, and again 20 to 25 d later to detect ewes that conceived to the second service period. Percentage of ewes marked by rams was higher in progesterone-treated (77%) than in C (20%; P < 0.01), but did not differ between P5 and P5F. The ovulation rate (1.95+/-0.04) did not differ due to FSH. Conception (68%) and pregnancy (52%) rates were higher in progesterone-treated (P < 0.01) than in C (0%) ewes. Estrous response varied quadratically with time after ram introduction, and the conception rate varied quadratically with the time of observation of onset of estrus. Over two service periods more progesterone-treated than C ewes lambed (65 vs 45%; P < 0.01). Lambs born per ewe exposed (0.7+/-0.1, 1.0+/-0.1, and 1.1+/-0.1 for C, P5 and P5F, respectively) was increased by progesterone (P < 0.05). Litter size to the first service period (1.59+/-0.04) and overall (1.54+/-0.03) did not differ among treatment groups. FSH-treated ewes tended to have more lambs (1.67+/-0.1) than did ewes receiving progesterone alone (1.5+/-0.1; P = 0.06) and than did ewes lambing to the second service period (1.5+/-0.1; P = 0.06). In summary, a 5-d progesterone pre-treatment of anestrous ewes induced estrous cycles and increased the pregnancy rates. A single injection of FSH only tended to increase litter size.
M Knights; T D Maze; P J Bridges; P E Lewis; E K Inskeep
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Theriogenology     Volume:  55     ISSN:  0093-691X     ISO Abbreviation:  Theriogenology     Publication Date:  2001 Mar 
Date Detail:
Created Date:  2001-04-26     Completed Date:  2001-06-07     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0421510     Medline TA:  Theriogenology     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1181-91     Citation Subset:  IM    
Division of Animal and Veterinary Sciences, West Virginia University, Morgantown 26506, USA.
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MeSH Terms
Drug Delivery Systems / veterinary*
Estrus / drug effects*,  physiology
Follicle Stimulating Hormone / administration & dosage*
Litter Size
Ovulation Induction / methods,  veterinary*
Pregnancy Outcome / veterinary
Progesterone / administration & dosage*
Random Allocation
Sheep / physiology*
Reg. No./Substance:
57-83-0/Progesterone; 9002-68-0/Follicle Stimulating Hormone

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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