Food availability in the environment is often low and variable, constraining organisms in their resource allocation to different life-history traits. For example, variation in food availability is likely to induce condition-dependent investment in reproduction. Further, diet has been shown to affect ejaculate size, composition and quality. How these effects translate into male reproductive succ...

In promiscuous species, male reproductive success depends on their ability to mate with fertile females and on the fertilizing ability of their sperm. In such species, theory predicts that, owing to a trade-off between pre- and post-copulatory reproductive traits, males with lesser access to females should increase resource investment into those sperm traits that enhance fertilization success-u...

Sperm are the most diverse cell type known: varying not only among- and within- species, but also among- and within-ejaculates of a single male. Recently, the causes and consequences of variability in sperm phenotypes have received much attention, but the importance of within-ejaculate variability remains largely unknown. Correlative evidence suggests that reduced within-ejaculate variation in ...

Experiments and field data on blue crab, Callinectes sapidus, from mid-Chesapeake Bay between 1991 and 1994 were used to test whether large males have advantages over small males in accessing females and in sperm competition. In the field, large males were paired more often, especially with large, more fecund females. However, the variance in the relationship between male and female size in mat...

Fertility Associated Antigen in Peripubertal Beef Bulls as an Indicator of Potential Fertility. (August 2005) Joanna Lynn Gallino, B.S., California State Polytechnic University Co-Chairs of Advisory Committee: Dr. L. R. Sprott Dr. D. W. Forrest Ejaculates from peripubertal Angus (n=106), Brahman (n=156) and Brangus (n=212) bulls were evaluated for the presence of a 31 kDa protein known as ferti...

The ability to predict the frozen semen doses produced per ejaculate would be of considerable benefit for management skill, human resource, capital and time. new computing paradigm called machine learning involves in predicting dependent variable by complex non-linear relationship among independent variables. purpose this study is develop prediction model using one conventional modelling techni...

to study clinical and histopathological changes occur within the first 12 hours of strangulating obstruction of the small intestine in equine, twenty five adult donkeys were used in an experimental study. strangulation obstruction of the small intestine was performed for 3, 6, 9 and 12 hours, respectively. clinical examination was done before surgery and at 3 hours intervals postoperatively. af...

The rat prostate comprises dorsal, ventral and lateral lobes that are morphologically and biochemically distinct. Lesions to these structures are expected to affect the quality of the ejaculate and male fertility. In experiment 1, we analyzed ejaculate parameters of males that had chemical lesions of the dorsal or ventral lobes. At pre-lesion and at 5 and 20 days post-lesion males were mated, a...

The study attempted to clarify the role of total antioxidant capacity of seminal plasma (SP-TAC) on boar sperm survival and fertility after artificial insemination (AI). SP-TAC differed (P < 0.001) among boars (n° = 15) and, to a lesser degree, among ejaculates within male (4 ejaculates/boar). SP-TAC also differed (P < 0.001) among ejaculate fractions (43 ejaculates and 3 fractions per ejaculat...