overall, 531 dairy cows were inseminated with the aim to study their reproductive performance following administration of gnrh analogue on different days of estrous cycle with different doses. these cows were divided into six treatment and one control group. depending upon different treatment groups, buserelin acetate was injected at a dose of 10.5 µg or 21.0 µg on different days (0, 5 or 12) o...

Improvement of reproduction in dairy cows has become a major challenge in dairy production. We have recently shown that dairy cows carrying the 'fertil-' haplotype for one quantitative trait locus (QTL), affecting female fertility and located on the bovine chromosome 3, had a significantly lower conception rate after the first artificial insemination than cows carrying the 'fertil+' haplotype. ...

This study had the objective of determining the fertility and calving ease of small holder indigenous cattle herds inseminated with imported semen from proven sires. Sixty one indigenous cows of different breed origin (Bunaji, Sokoto Gudali and Rahaji) were selected from different herds across Jigawa state-Nigeria, and were used for this study. The selected dams were inseminated with semen from...

The high producing dairy cow of the 21st century is subfertile during lactation. Our objectives are to characterize physiological periods limiting reproductive performance and to describe integrated management strategies to improve pregnancy rates. Ovarian recrudescence with normal re-occurring estrous cycles and restoration of fertility to first service are associated with a reduced occurrence...

BACKGROUND Synchronization programs have become standard in the dairy industry in many countries. In Switzerland, these programs are not routinely used for groups of cows, but predominantly as a therapy for individual problem cows. The objective of this study was to compare the effect of a CIDR-Select Synch and a 12-d CIDR protocol on the pregnancy rate in healthy, multiparous dairy cows in Swi...

Ovarian follicle development continues in a wave-like manner during the bovine oestrous cycle giving rise to variation in the duration of ovulatory follicle development. The objectives of the present study were to determine whether a relationship exists between the duration of ovulatory follicle development and pregnancy rates following artificial insemination (AI) in dairy cows undergoing spon...

To evaluate an artificial insemination program in postpartum Bos indicus cows and by using deterministic models, to estimate the possible economic advantages of insemination by appointment over detected estrus, sixty-three multiparous animals were synchronized using a progestagen device inserted at day 31 and withdrawn after 9 days (average time for withdrawal was 40.9 ± 6.8 days). Cows were ob...

The aim of this trial was to compare the effect complete replacement certain inorganic trace minerals with organic, chelated (Bioplex®, Selplex®; Alltech Inc, USA) against standard and reduced mineral levels in feed on performance health dairy cows during a 10-week (W0-W10) period. Three treatment groups, each containing 36 cows, were assigned one three diets that varied only composition: (1) I...

Thirty nonlactating Holstein cows were superovulated to determine the effect of artificial insemination time on fertilization status and embryo quality. During the luteal phase of the estrous cycle, cows were administered 38 mg FSH-P in a 4-d descending dose regimen. Luteolysis was induced with two injections of prostaglandin on the last day of FSH-P treatment. All cows were continuously monito...