Reduced gonadotroph stimulation by ethanolamine plasmalogens in old bovine brains.

Ethanolamine plasmalogens (EPls), unique alkenylacyl-glycerophospholipids, are the only known ligands of G-protein-coupled receptor 61-a novel receptor co-localised with gonadotropin-releasing hormone receptors on anterior pituitary gonadotrophs. Brain EPl decreases with age. Commercial EPl-extracted from the cattle brain (unidentified age)-can independently stimulate FSH secretion from gonadotrophs. We hypothesised that there exists an age-related difference in the quality, quantity, and ability of bovine brain EPls to stimulate bovine gonadotrophs. We compared the brains of young (about 26 month old heifers) and old (about 90 month old cows) Japanese Black bovines, including EPls obtained from both groups. Additionally, mRNA expressions of the EPl biosynthesis enzymes, glyceronephosphate O-acyltransferase, alkylglycerone phosphate synthase, and fatty acyl-CoA reductase 1 (FAR1) were evaluated in young and old hypothalami. The old-brain EPl did not stimulate FSH secretion from gonadotrophs, unlike the young-brain EPl. Molecular species of EPl were compared using two-dimensional liquid chromatography-mass spectrometry. We identified 20 EPl molecular species of which three and three exhibited lower (P < 0.05) and higher (P < 0.05) ratios, respectively, in old compared to young brains. In addition, quantitative reverse transcription-polymerase chain reaction detected higher FAR1 levels in the POA, but not in the ARC&ME tissues, of old cows than that of fertile young heifers. Therefore, old-brain EPl may be associated with age-related infertility.

Decreased Anti-Müllerian hormone and Anti-Müllerian hormone receptor type 2 in hypothalami of old Japanese Black cows.

Cow fertility decreases with age, but the hypothalamic pathomechanisms are not understood. Anti-Müllerian hormone (AMH) stimulates gonadotropin-releasing hormone (GnRH) neurons via AMH receptor type 2 (AMHR2), and most GnRH neurons in the preoptic area (POA), arcuate nucleus (ARC), and median eminence (ME) express AMH and AMHR2. Therefore, we hypothesized that both protein amounts would differ in the anterior hypothalamus (containing the POA) and posterior hypothalamus (containing the ARC and ME) between young post-pubertal heifers and old cows. Western blot analysis showed lower (P<0.05) expressions of AMH and AMHR2 in the posterior hypothalamus, but not in the anterior hypothalamus, of old Japanese Black cows compared to young heifers. Therefore, AMH and AMHR2 were decreased in the posterior hypothalami of old cows.

"Clean, green and ethical" animal production. Case study: reproductive efficiency in small ruminants.

In response to changes in society and thus the marketplace, we need a vision for the future of our animal industries, including both on-farm and off-farm activities, that is "clean, green and ethical". Using small ruminants as a case study, we describe three "clean, green and ethical" strategies that farmers could use to improve reproductive performance. The first allows control of the timing of reproductive events by using socio-sexual signals (the "male effect") to induce synchronised ovulation in females. The second strategy, "focus feeding", is based on using short periods of nutritional supplements that are precisely timed and specifically designed for each event in the reproductive process (eg, gamete production, embryo survival, fetal programming, colostrum production). The third strategy aims to maximize offspring survival by a combination of management, nutrition and genetic selection for behaviour (temperament). All of these approaches involve non-pharmacological manipulation of the endogenous control systems of the animals and complement the detailed information from ultrasound that is now becoming available. Importantly, these approaches all have a solid foundation in reproductive biology. In several cases, they are currently used in commercial practice, but there is still room for improvement through both basic and applied research. Ultimately, these "clean, green and ethical" tools can be cost-effective, increase productivity and, at the same time, greatly improve the image of meat and milk industries in society and the marketplace.