Male reproductive traits and their relationship to reproductive traits in their female progeny: a systematic review

The overall objective of one of the major research programs in the Co-operative Research Centre (CRC) for Beef Genetic Technologies is to 'Improve female reproductive performance' in tropical, northern Australian beef cattle herds. To address this overall objective, a quantitative genetics project focused on investigation of male reproductive traits was designed and linked to three female reproduction-focussed projects, (i) discovery of genes associated with post-partum re-conception and age at puberty; (ii) expression of genes associated with post-partum re-conception; and (iii) early predictors of lifetime female reproductive performance. During the initial planning of this male reproductive traits project, the CRC Scientific Review Committee recommended that the research team investigate and evaluate potentially new, early-life (i.e able to be measured before 2 years of age) predictors of both male and female reproductive performance. To address this recommendation, the following was carried out: (i) criteria for selection of traditional and candidate traits were established; (ii) methodology for tabulation of potential traits/phenotypes that define male and female reproductive function was developed; and (iii) a systematic scientific review of early-life predictors of male and female fertility was prepared. This review concluded that although factors that might be useful in predicting male reproductive performance have been studied for many years, there was relatively little useful information available to meet the objectives of this review. It was also concluded that the direction of future research should be guided not only by previous research which was scarce, but also by speculative hypotheses arising from an understanding of the physiological, endocrinological and genetic processes active in reproduction. A small number of new traits were recommended in addition to traditional sperm morphology, sexual behaviour, anatomical structure and growth traits. Potential additional traits include measurement of gonadotrophin-releasing hormone-stimulated luteinizing hormone (GnRH-stimulated LH); inhibin; several seminal plasma proteins (osteopontin, spermadhesin and seminal plasma proteins BSP30 and phospholipase A(2) could be used in an index); 11β-hydroxysteriod dehydrogenase; and leptin. In addition, the potential also exists to screen animals for a number of genetic markers associated with age of puberty, follicular recruitment and ovulation rate and genes associated with bovine seminal plasma protein and testosterone production. Insulin-like growth factor-1 (IGF-1) measurements are included because of their association with growth parameters, and an additional analysis demonstrated associations with male and female reproductive traits. Some of these factors have been previously evaluated in small numbers of animals of various species under intensive management conditions. Therefore, there is a need to evaluate these factors in much larger numbers of beef cattle grazing semi-extensive tropical production systems in northern Australia to determine their value in improving beef cattle enterprise profitability through improved herd fertility.     

Technical note: Use of near-infrared reflectance spectroscopy to predict intake and digestibility in bulls and steers

Multiple fecal samples were collected from growing Angus bulls (264 to 419 kg of BW, 3.0 to 11.4 kg/d of DMI) to predict DMI of a corn-silage-based diet. Contemporaneous digestion trials were conducted with the same diet in 12 steers in yr 1 to 3 and bulls in yr 4. Near-infrared spectra from fecal samples (n = 730 from 282 growing bulls, n = 240 from 36 steers and 12 bulls for digestion trials) were obtained from dried and ground fecal samples, and modified partial least squares regression was used to develop equations to predict DMI and DM digestibility (DMD). Although mean predicted DMI of the growing bulls (7.52 ± 0.04 kg/d or 22.4 ± 0.1 g/kg of BW) was within 2% of mean measured DMI (7.63 ± 0.06 kg/d or 22.7 ± 0.1 g/kg of BW), the mean of paired differences within samples (0.11 ± 0.04 kg/d or 0.3 ± 0.1 g/kg of BW) was greater (P < 0.01) than zero. Measured DMD (72.3 ± 0.5%) was identical (P < 0.97) to predicted DMD (72.3 ± 0.5%), and DMD for bulls in the digestion trial did not differ (P < 0.27) from DMD for steers. Prediction of intake requires incorporation of some measured values from the set of fecal samples to be predicted. Lack of similarity between spectra of fecal grab samples from the growing bulls and daily fecal collection of steers and bulls in the digestion trials in this study indicates the need for further verification before prediction of DMD with fecal grab samples.     

Concurrent nephrosplenic entrapment and acquired inguinal herniation of the jejunum in a Standardbred stallion

A stallion presenting for surgical correction of an acquired inguinal hernia was also diagnosed with a nephrosplenic entrapment (NSE) intraoperatively. Surgical intervention resulted in a successful outcome. To date, these conditions have not been reported to occur simultaneously.