Syferkuil Dam is situated 8 km NW of the University of the North and comprises a series of eight interconnected rectangular dams, having cement sides and mud bottoms. Throughout the experimental period, male and female adult specimens of the mouthbrooding tilapia, Oreochromis mossambicus were collected for further analysis. Aspects of the reproductive physiology of O. mossambicus that were inve...

We evaluated hypotheses concerning temporal, landscape, and habitat effects on nest survival of golden-cheeked warblers (Dendroica chrysoparia) in an urban and a rural landscape during the breeding seasons of 2005 and 2006 in central Texas, USA. We found support for temporal effects of year and cubic effect of date and included them in candidate models that evaluated habitat and landscape effec...

Seasonality is an important component in many population systems, and factors such as latitude, altitude and proximity to the coastline affect the extent of the seasonal fluctuations. In this paper, we ask how changes in seasonal fluctuations impact on the population cycles. We use the Fennoscandian vole system as a case study, focusing on variations in the length of the breeding season. We use...

The objective of the breeding herd is the predictable and consistent production of high quality pigs. To achieve this objective, an appropriate number of females need to be mated in each breeding week and they should maintain their pregnancy and deliver large litters. Many factors can impact achievement of optimal sow productivity, particularly breeding management. Most matings will involve art...

Genetic diversity in the Finnsheep breed was analyzed by quantifying the demographic trends, the depth of known pedigree, effective population size, and the amount of inbreeding, as well as identifying candidate rams within the current population for future breeding and conservation purposes. Pedigree records of 148,833 animals with a pedigree completeness coefficient > or =0.60 and born from 1...

Tropical bird species usually have lower testosterone (T) levels during breeding than temperate species. However, the potential mechanisms behind the positive interspecific correlation between T and latitude remain unexplored. In a comparative study of more than 100 bird species, we examined whether social constraints during male-male competition arising from migration and breeding synchrony ar...

Recently, a shift in preen wax composition, from lower molecular weight monoesters to higher molecular weight diesters, was described for individuals of a sandpiper species (red knot, Calidris canutus) that were about to leave for the tundra breeding grounds. The timing of the shift indicated that diester waxes served as a quality signal during mate choice. Here, this hypothesis is evaluated on...

The records of 1085 crossbred cattle daughters of 57 sires maintained during 1974-2004 at Instructional Dairy Farm of Govind Ballabh Pant University of Agriculture & Technology, Pantnagar, Uttarakhand, India were used to evaluate sires for first lactation performance traits. The data were analyzed to estimate the breeding values of sires using least squares methods (LSM), best linear unbiased p...

We analysed growth of nestling Chilean Swallows (Tachycineta meyeni) over four consecutive breeding seasons and determined the factors that explain variation in growth rate, asymptotic body mass and length of the nestling period. As the breeding season advanced nestlings grew more slowly and attained lower asymptotic mass, but the length of the nestling period and nestling survival did not show...

In December 1991, we initiated a long-term study of the California Tiger Salamander (Ambystoma californiense) at a breeding pond in Monterey County, California. Because of habitat loss, this species is a candidate for federal endangered species status, but many basic features of its life history and demography have not been studied in detail. During the first seven years of this study, we captu...