147 Presynchronization and delayed fixed-time artificial insemination increases pregnancy rates with sex-sorted semen in replacement beef heifers
نویسندگان
چکیده
منابع مشابه
Delayed insemination of nonestrous cows improves pregnancy rates when using sex-sorted semen in timed artificial insemination of suckled beef cows.
This experiment was designed to test the hypothesis that delayed insemination of nonestrous cows would increase pregnancy rates when using sex-sorted semen in conjunction with fixed-time artificial insemination (FTAI). Estrus was synchronized for 656 suckled beef cows with the 7-d CO-Synch + controlled internal drug release (CIDR) protocol (100 μg GnRH + CIDR [1.38 g progesterone] on d 0, 25 mg...
متن کاملFixed-time artificial insemination in beef cattle
BACKGROUND The study was designed to test the effect of fixed-time artificial insemination (fixed-AI) after the slightly modified Ovsynch protocol on the pregnancy rate in beef cattle in Finnish field conditions. The modification was aimed to optimize the number of offsprings per AI dose. METHODS Ninety Charolais cows and heifers were entered into the program an average of 1.8 times. Thus, 16...
متن کاملFixed-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 کاملFactors affecting pregnancy rate to estrous synchronization and fixed-time artificial insemination in beef cattle.
Application of AI in extensive beef cattle production would be facilitated by protocols that effectively synchronize ovarian follicular development and ovulation to enable fixed-time AI (TAI). The objectives were to determine whether use of a controlled internal drug release (CIDR) device to administer progesterone in a GnRH-based estrous synchronization protocol would optimize blood progestero...
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ژورنال
عنوان ژورنال: Journal of Animal Science
سال: 2020
ISSN: 0021-8812,1525-3163
DOI: 10.1093/jas/skaa278.211