This study investigated the effects of gonadotrophin-releasing hormone (GnRH) administration (Experiment 1) and a controlled internal drug-releasing (CIDR) insert (Experiment 2) after timed artificial insemination (TAI) on the pregnancy rates of dairy cows. In Experiment 1, 569 dairy cows that underwent TAI (day 0) following short-term synchronization with prostaglandin F2α were randomly alloca...

This study evaluated the effect of resynchronization programs on pregnancies in dairy cows. Of 1,342 cows confirmed not pregnant after their first artificial insemination (AI), those with a corpus luteum (CL) were resynchronized using Ovsynch or PG-GnRH-Ovsynch and without CL GnRH-Ovsynch modified Double-Ovsynch. There no differences (p > 0.05) per AI either between (31.3%) (34.0%) (38.7%) D...

The objective of this study was to determine the effect of GnRH (100 microg i.m.) treatment 5 and 15 days after timed insemination (TAI) on pregnancy rate and pregnancy loss in lactating dairy cows subjected to synchronization of ovulation. The study included 831 lactating dairy cows subjected to a Presynch-Ovsynch protocol for first service. On the day of TAI (Day 0), cows were randomly assign...

Using two PGF(2α) treatments 14 days apart as a way to enhance estrus detection rate following the 2nd treatment is a reproductive management tool that continues to be used on large dairy farms. In one study, in cows with a functional CL and a dominant follicle, treatment with cloprostenol vs. dinoprost resulted in greater peripheral estradiol concentrations. The objective of the present study ...

The objectives of the present study were to determine the effects of resynchronization with GnRH on Day 21 after artificial insemination (AI) on pregnancy rate and losses of pregnancy in lactating dairy cows. Holstein cows (n=585) on two dairy farms were assigned to one of two treatments in a randomized complete block design. On Day 21 after a pre-enrollment AI, animals assigned to the resynchr...

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=300...

The use of vaginal electrical resistance (VER) for estrous detection and early pregnancy diagnosis were evaluated using three experiments in dairy cattle, in Ethiopia. VER was measured: 1) during the natural estrous (n = 60) cycle, 2) during estrus induced by GnRH+ PGF2· (n = 11) and 3) during post insemination in dairy cows synchronized with GnRH+CIDR+PGF2· (n = 25). Results from Experiment 1 ...

ABSTRACT. Penelitian ini bertujuan mengevaluasi keberhasilan IB menggunakan metode dosis tunggal dan ganda pada sapi Madura. 25 ekor dengan ganda. semen beku Madura yang diproduksi oleh Balai Besar Inseminasi Buatan (BBIB) Singosari, Malang. Teknik deposisi adalah 4+ (deep insemination) yaitu posisi cornua uteri selanjutnya dilakukan (jam ke-8 setelah menunjukkan tanda-tanda berahi) ke-2 berahi...

Gunay A., U. Gunay: Effects of Clinical Mastitis on Reproductive Performance in Holstein Cows. Acta Vet. Brno 2008, 77: 555-560. The objective of this study was to determine the effects of clinical mastitis on reproductive performance in 135 early lactation cows. The animals were divided into two groups according to the occurrence of mastitis as follows: group I (n = 45), clinical mastitis prio...

The study was conducted to know the effect of flushed feeding on estrus synchronization and conception rate of Holstein ÍLocal crossbred cow’s after using the GnRH (fertagyl) and PGF2α hormone. As a representative sample 20 Holstein ÍLocal crossbred cows were chosen from Chittagong Cantonment Military Dairy Farm in Bangladesh and the experimental work was carried out for 60 days. Ten cows were ...