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פותח על ידי קלירמאש פתרונות בע"מ -
Influence of gonadotropin-releasing hormone and timing of insemination relative to estrus on pregnancy rates of dairy cattle at first service.
Year:
1990
Source of publication :
Journal of Dairy Science
Authors :
פולמן, ישעיהו
;
.
Volume :
73
Co-Authors:
Mee, M.O., Department of Animal Sciences and Industry, Kansas State University, Manhattan 66506.
Stevenson, J.S., Department of Animal Sciences and Industry, Kansas State University, Manhattan 66506.
Scoby, R.K., Department of Animal Sciences and Industry, Kansas State University, Manhattan 66506.
Folman, Y., Department of Animal Sciences and Industry, Kansas State University, Manhattan 66506.
Facilitators :
From page:
1500
To page:
1507
(
Total pages:
8
)
Abstract:
The objective was to determine the influence of gonadotropin-releasing hormone on pregnancy rates of dairy cattle at first services, when both the timing of hormone injection and insemination were altered relative to the onset of estrus. Cows (n = 325) were assigned randomly to six groups making up a 2 X 2 X 2 incomplete factorial experiment; dose of GnRH (100 micrograms versus saline), timing [1 h (early) or 12 to 16 h (late) after first detected estrus] of AI, and timing of hormone injection (early versus late) were the three main effects. Cows were observed for estrus 4 times daily. Treatments and resulting pregnancy rates were: 1) hormone injection early plus AI early (35%), 2) hormone injection late plus AI early (34%), 3) saline injection early plus AI early (30%), 4) hormone injection late plus AI late (30%), 5) hormone injection early plus AI late (46%), and 6) saline injection late plus AI late (43%). Pregnancy rate in the first four groups (32%) was less than that in the latter two groups (44%). Concentrations of LH in serum were greater for cows given hormone or saline injections in early estrus than for cows injected with either hormone of saline during late estrus. Concentrations of LH in serum 2 h after GnRH were elevated above those of controls, whether GnRH was injected during early or late estrus. Neither concentrations of LH during estrus nor concentrations of progesterone 8 to 14 d after estrus explained the possible antifertility effect of GnRH given during late estrus.(ABSTRACT TRUNCATED AT 250 WORDS)
Note:
Related Files :
Animal
artificial insemination
Blood
cattle
drug effect
Estrus Detection
Female
pregnancy
Random Allocation
עוד תגיות
תוכן קשור
More details
DOI :
Article number:
Affiliations:
Database:
סקופוס
Publication Type:
מאמר
;
.
Language:
אנגלית
Editors' remarks:
ID:
22925
Last updated date:
02/03/2022 17:27
Creation date:
16/04/2018 23:55
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Scientific Publication
Influence of gonadotropin-releasing hormone and timing of insemination relative to estrus on pregnancy rates of dairy cattle at first service.
73
Mee, M.O., Department of Animal Sciences and Industry, Kansas State University, Manhattan 66506.
Stevenson, J.S., Department of Animal Sciences and Industry, Kansas State University, Manhattan 66506.
Scoby, R.K., Department of Animal Sciences and Industry, Kansas State University, Manhattan 66506.
Folman, Y., Department of Animal Sciences and Industry, Kansas State University, Manhattan 66506.
Influence of gonadotropin-releasing hormone and timing of insemination relative to estrus on pregnancy rates of dairy cattle at first service.
The objective was to determine the influence of gonadotropin-releasing hormone on pregnancy rates of dairy cattle at first services, when both the timing of hormone injection and insemination were altered relative to the onset of estrus. Cows (n = 325) were assigned randomly to six groups making up a 2 X 2 X 2 incomplete factorial experiment; dose of GnRH (100 micrograms versus saline), timing [1 h (early) or 12 to 16 h (late) after first detected estrus] of AI, and timing of hormone injection (early versus late) were the three main effects. Cows were observed for estrus 4 times daily. Treatments and resulting pregnancy rates were: 1) hormone injection early plus AI early (35%), 2) hormone injection late plus AI early (34%), 3) saline injection early plus AI early (30%), 4) hormone injection late plus AI late (30%), 5) hormone injection early plus AI late (46%), and 6) saline injection late plus AI late (43%). Pregnancy rate in the first four groups (32%) was less than that in the latter two groups (44%). Concentrations of LH in serum were greater for cows given hormone or saline injections in early estrus than for cows injected with either hormone of saline during late estrus. Concentrations of LH in serum 2 h after GnRH were elevated above those of controls, whether GnRH was injected during early or late estrus. Neither concentrations of LH during estrus nor concentrations of progesterone 8 to 14 d after estrus explained the possible antifertility effect of GnRH given during late estrus.(ABSTRACT TRUNCATED AT 250 WORDS)
Scientific Publication
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