Fertility of Dairy Cows after Resynchronization of Ovulation at Three Intervals Following First Timed Insemination
نویسندگان
چکیده
منابع مشابه
Effect of interval from timed artificial insemination to initiation of resynchronization of ovulation on fertility of lactating dairy cows.
To compare 2 strategies for systematically resynchronizing ovulation, lactating Holstein cows (n = 763) at various days in milk and prior artificial insemination services were assigned randomly at timed AI (TAI) to receive the first GnRH injection of Ovsynch 26 (D26) or 33 (D33) d after TAI to resynchronize ovulation (Resynch) in cows failing to conceive. Cows in the D26 treatment received GnRH...
متن کاملResynchronization of ovulation and timed insemination in lactating dairy cows I: use of the Ovsynch and Heatsynch protocols after non-pregnancy diagnosis by ultrasonography.
The objective was to compare pregnancy rates and pregnancy losses in lactating dairy cows that were diagnosed not pregnant and re-inseminated following either the Ovsynch or Heatsynch protocols. Also evaluated were the effects of stages of the estrous cycle, ovarian cysts and anestrus on pregnancy rates for both treatments. Non-pregnant cows (n = 332) as determined by ultrasonography on day 27 ...
متن کاملResynchronization of ovulation and timed insemination in lactating dairy cows, II: assigning protocols according to stages of the estrous cycle, or presence of ovarian cysts or anestrus.
Pregnancy rates were compared in lactating dairy cows (n = 1083) assigned to protocols for resynchronization of ovulation based on stages of the estrous cycle, or presence of ovarian cysts or anestrus. Cows were detected not pregnant by ultrasonography 30 d after a previous AI (study day 0) and classified as diestrus, metestrus, proestrus, with ovarian cysts or anestrus. Cows in diestrus (Janua...
متن کاملEffect of GnRH injection at day 6 and 12 after insemination on fertility of Holstein dairy cows during the warm season
The objective of this study was to determine the effects of two different time of GnRH injection after artificial insemination (A.I) (d 6 and d 12) on reproductive performances of Holstein cows during the warm season. Cows randomly assigned to treatments 1) No GnRH injection (control, n = 300),2) GnRH injection at day 6 after A.I (G6, n=300) and 3) GnRH injection at day 12 after A.I (G12, n=30...
متن کاملResynchronization of ovulation and timed insemination in lactating dairy cows III. Administration of GnRH 23 days post AI and ultrasonography for nonpregnancy diagnosis on day 30.
The objective was to compare pregnancy rates to resynchronization and timed AI (TAI) protocols in lactating dairy cows that received GnRH at 23 d and were diagnosed not pregnant at 30 d after the pre-enrollment AI. Nonpregnant cows (624) at ultrasonography on day 30 (study day 0) were classified as diestrus (74.8%), metestrus (5.6%) and without a CL (19.5%). Cows in diestrus were assigned eithe...
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ژورنال
عنوان ژورنال: Journal of Dairy Science
سال: 2003
ISSN: 0022-0302
DOI: 10.3168/jds.s0022-0302(03)74003-x