Prior tests of interfertility among 3 partly sympatric species of the Rana pipiens complex (R. berlandieri, R. blairi, and R. sphenocephala) have indicated poor development of postmating reproductive isolation. However, hybrids are uncommon in sympatric populations, so premating isolation must exist. Among the species studied, temporal isolation predominates. In areas of tri-sympatry, the breed...

#10 Seasonal breeding and calving is often used. Seasonal breeding and calving are not required to have a successful pasture-based dairy farm but cows bred to calve in one or possibly two compact seasons can simplify animal management. Use of two calving seasons allows more consistent year-round production of milk if that is of concern for cash flow or is a requirement for marketing milk. Poten...

Individuals of many species form bonds with their breeding partners, yet the mechanisms maintaining these bonds are poorly understood. In birds, allopreening is a conspicuous feature of interactions between breeding partners and has been hypothesized to play a role in strengthening and maintaining pair bonds within and across breeding attempts. Many avian species, however, do not allopreen and ...

Two mature breeding stallions were evaluated because of specific ejaculatory dysfunction, and each was found to have aortic-iliac thrombosis occluding 60 to 70% of the aortic lumen. In each case, the stallion had strong libido, normal mounting, and vigorous initial thrusting. With continued exertion, thrusting became weak and dismount was awkward. Treatment aimed at maximizing sexual arousal be...

The present study was conducted to investigate the impact of breeding season on the productivity and profitability of Barki flock. Simulation technique was used based on technical coefficients derived from statistical analysis of the basic data. Basic data utilized in this study were obtained from the accumulated records collected over 34 successive breeding seasons from 1972 to 2005 of Barki s...

The European beaver (Castor fiber L.) is an important free-living rodent that inhabits Eurasian temperate forests. Beavers are often referred to as ecosystem engineers because they create or change existing habitats, enhance biodiversity and prepare the environment for diverse plant and animal species. Beavers are protected in most European Union countries, but their genomic background remains ...

This study was aimed to evaluate the effect of GnRH injection on semen ejaculate characteristics in Awassi rams collected in breeding and non breeding seasons. The study was conducted in late summer to early autumn when breeding activity commences, and in winter during the non breeding season. Twelve mature Awassi rams were used in this study. Animals were randomly allocated into two equal grou...

Reproductive success usually declines in the course of the season, which may be a direct effect of breeding time, an effect of quality (individuals with high phenotypic or environmental quality breeding early), or a combination of the two. Being able to distinguish between these possibilities is crucial when trying to understand individual variation in annual routines, for instance when to bree...