Multiparous Suffolk and Suffolk-cross ewes were randomly allotted to treatments within breed and year to measure effects of ram exposure, during transition from anestrus to breeding activity, on reproductive performance. Treatments were: 1) ewes joined with two mature vasectomized Rambouillet rams for 15 d before breeding (DC), 2) ewes maintained across a net wire fence from two vasectomized ra...

Nutritionally induced changes in growth hormone (GH) and IGF-I are associated with decreased ovarian function and may partially explain infertility and anestrus in undernourished cattle. The reproductive importance of GH and IGF-I was tested in cattle with a GH receptor deficiency (GHRD) that have reduced blood IGF-I. Blood was collected daily for plasma, and ovaries were examined daily by ultr...

During summer and early fall, many sow farms experience a variety of reproductive problems, such as, anestrus, extended weaning-to-estrus intervals, poor conception rates, higher embryo mortality rates and low farrowing rates. This phenomenon is commonly referred to as “seasonal infertility” and can also be present in boar studs, where the result is lower semen output and lower semen quality. M...

Pheromones are involved in communication between con-specific members of different species of insects, birds and mammals. Numerous works have been carried out in insects, wild animals, small ruminants and in pig. However, in cattle and particularly buffaloes, application of pheromones have been tried to augment reproductive efficiency only in the recent years. This review covers in detail about...

Nutrition has an important impact on the reproductive performance of dairy cattle. Energy is the major nutrient required by adult cattle and inadequate energy intake has a detrimental impact on reproductive activity of the female bovine. Cows under negative energy balance have extended periods of anovulation. Postpartum anestrus, as well as infertility, is magnified by losses of body condition ...

The objective of this study was to compare linear models and survival analysis for genetic evaluation of ovulatory disorders, which included veterinary treatments of silent heat/anestrus and cystic ovaries. Data of 23 450 daughters of 274 Austrian Fleckvieh sires were analyzed. For linear model analyses, ovulatory disorders were defined as a binary response (presence or absence) in the time per...

This study was conducted at the Bukhara breeding centre (Ouzbekistan, Central Asia) on Persian gazelles (Gazella subgutturosa subgutturosa) and at Thumammah (Saudi Arabia) on sand gazelles (Gazella subgutturosa marica). Plasma prolactin (PRL) and progesterone were determined in groups of females. Because these females were under two different photoperiods (20 degrees N in Saudi Arabia and 40 de...

A deterministic mathematical computer model was developed to simulate effects on life-cycle efficiency of lamb and wool production from genetic improvement of performance traits under alternative management systems. Genetic input parameters can be varied for age at puberty, length of anestrus, fertility, precocity of fertility, number born, milk yield, mortality, growth rate, body fat, and wool...

Endometrial matrix metalloproteinases (MMPs) are extensively studied in humans. However, owing to the distinct differences of the estrous cycle of bitches, the expression and activities of endometrial MMPs regulated by sex hormones should be significantly different. To understand the effect of sex hormones on the activity of MMPs, this study investigates the activities of endometrial MMP-2 and ...

Nutrition has an important impact on the reproductive performance of dairy cattle. Energy is the major nutrient required by adult cattle, and inadequate energy intake has a detrimental impact on reproductive activity of the female bovine. Cows under negative energy balance have extended periods of anovulation. Postpartum anestrus, as well as infertility, is magnified by losses of body condition...