Reproductive Performance of Dairy Heifers after Estrus Synchronization and Fixed-Time Artificial Insemination
نویسندگان
چکیده
منابع مشابه
Fixed-time artificial insemination in replacement beef heifers after estrus synchronization with human chorionic gonadotropin or gonadotropin-releasing hormone.
We determined the effects of hCG on ovarian response, concentration of progesterone, and fertility in a fixed-time AI (TAI) protocol. Four hundred forty-four crossbred beef heifers were synchronized with the CO-Synch + CIDR (controlled internal drug-releasing insert) protocol. In addition, heifers were randomly assigned to 1 of 4 treatments in a 2 × 2 factorial arrangement of treatments with ma...
متن کاملComparison of progestin-based estrus synchronization protocols before fixed-time artificial insemination on pregnancy rate in beef heifers.
The objective of the experiment was to compare pregnancy rates resulting from fixed-time AI after administration of either 1 of 2 controlled internal drug release (CIDR)-based protocols. Heifers at 3 locations (location 1, n = 78; location 2, n = 61; and location 3, n = 78) were assigned to 1 of 2 treatments within reproductive tract scores (1 = immature to 5 = cycling) by age and BW. Heifers a...
متن کاملEffect of prostaglandin F2α and GnRH administration at the time of artificial insemination on reproductive performance of dairy cows
The present study aimed to determine the effect of administrating prostaglandin F2α (PGF2α) and GnRH at the time of artificial insemination (AI) on the pregnancy per artificial insemination (P/AI) and the pregnancy survival rate of dairy cows. A number of 830 lactating Holstein cows were randomly divided into four groups. Cows in group 1 (n=200) treated with 150 µg d-cloprostenol. In group 2 (n...
متن کاملKeys to Successful Estrus Synchronization and Artificial Insemination Programs
Introduction The development of effective methods of synchronizing estrus and ovulation has been based on our understanding of the physiological and hormonal mechanisms controlling the estrous cycle and the initiation of estrous cyclicity and prepuberty in heifers and postpartum cows. Although estrus synchronization products (PGF2, MGA, CIDR and GnRH) and protocols have changed over time, the ...
متن کاملComparison of long-term progestin-based protocols to synchronize estrus before fixed-time artificial insemination in beef heifers.
Two experiments were conducted to compare pregnancy rates resulting from fixed-time AI (FTAI) after administration of 1 of 2 long-term controlled internal drug release (CIDR)-based protocols. Heifers were assigned to treatment by age, BW, and pubertal status. The CIDR Select-treated heifers (Exp. 1, n = 37; Exp. 2, n = 192) received a CIDR (1.38 g of progesterone) from d 0 to 14, followed by 10...
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ژورنال
عنوان ژورنال: Journal of Dairy Science
سال: 1999
ISSN: 0022-0302
DOI: 10.3168/jds.s0022-0302(99)75309-9