No abstract

An analysis on the outcome of 124 inseminations monitored using daily milk progesterone concentration data revealed that those cows in which pregnancy did not occur experienced a 1.7day delay in post-ovulatory luteal progesterone rise when compared to the pregnant group (P<0.001). This suggests that luteal progesterone secretion needs to be initiated prior to day 5 post-ovulation. A comparison between the milk progesterone concentration on day 5 post-ovulation and the pregnancy rate for 1451 inseminations showed the maximum pregnancy rate to occur when the milk progesterone concentration was between 3-9ng/ml. Pregnancy rate fell significantly (P<0.01) when progesterone concentrations were below 3ng/ml, identifying cows that may benefit from progesterone supplementation. The supplementation of progesterone in cows with a day 5 milk progesterone concentration of less than 3ng/ml, using an intra-vaginal progesterone releasing device, only provided benefit for those cows with a day 5 progesterone concentration of between 1-2ng/ml, resulting in a doubling of the pregnancy rate. This data shows that a delay in post-ovulatory progesterone secretion has a detrimental effect on pregnancy but that not all cows with a deficient progesterone concentration benefit from progesterone supplementation.

No abstract

The Cleveland Bay horse is one of the oldest equines in the United Kingdom, with pedigree data going back almost 300 years. The studbook is essentially closed and because of this, there are concerns about loss of genetic variation across generations. The breed is one of five equine breeds listed as “critical” (<300 registered adult breeding females) by the UK Rare Breeds Survival Trust in their annual Watchlist. Due to their critically endangered status, the current breadth of their genetic diversity is of concern, and assessment of this can lead to improved breed management strategies. Herein, both genealogical and molecular methods are combined in order to assess founder representation, lineage, and allelic diversity. Data from 15 microsatellite loci from a reference population of 402 individuals determined a loss of 91% and 48% of stallion and dam lines, respectively. Only 3 ancestors determine 50% of the genome in the living population, with 70% of maternal lineage being derived from 3 founder females, and all paternal lineages traced back to a single founder stallion. Methods and theory are described in detail in order to demonstrate the scope of this analysis for wider conservation strategies. We quantitatively demonstrate the critical nature of the genetic resources within the breed and offer a perspective on implementing this data in considered breed management strategies.

Blood plasma concentrations of 13,14-dihydro-15-keto PGF2\g=a\(PGFM) were Furthermore, reduction in the amount of PGF2\g=a\ released is associated with luteal maintenance and the embryonic signal for maternal recognition of pregnancy must be transmitted before day 10 after ovulation if luteostasis is to be achieved. However, the results also indicate that, in contrast to ruminants, the release of endometrial PGF2\g=a\ in the non-pregnant camel may not be controlled by the release of oxytocin.