Teaching animal science and genetics to Australian university undergraduates to enhance inquiry-based student learning and research with sheep: growth and conformation traits in crossbred prime lambs

The primary objective of this Australian Wool Education Trust funded teaching initiative on inquiry-based learning and research-led teaching approach was to enhance students' critical thinking and target their learning needs through active participation in hands-on experience with experimental sheep. The secondary objective was to study the effects of sire breed and sex on growth and body conformation traits in crossbred prime lambs at the University of Tasmania Farm, Cambridge. Body weight, average daily gain, body condition score, body length, withers height and chest girth in sixty first cross Merino lambs sired by White Suffolk and Poll Dorset rams were measured fortnightly over a ten-week period. Generalised linear model procedure in SAS was used for statistical analysis and included the fixed effects of sire breed, sex, fortnight and their second order interactions. Duncan's Multiple Range Test, correlations between growth and conformation traits and Bonferroni probabilities were estimated and used for comparisons.\ud \ud A fortnightly increase in lamb body weight, average daily gain and body condition score was evident. Wethers were heavier and had higher average daily gains than ewes. White Suffolk sired progeny had higher average daily gains than those sired by Dorset rams, but body weight did not differ between sire breeds. However, a highly significant interaction (P<0.0001) between sire breed and sex on body weight was evident as White Suffolk sired wethers were the heaviest prime lambs. It was concluded that the real world, hands-on research experience with experimental sheep, field trips, data collection, statistical analyses, data interpretation and seminar presentation of results facilitated a deeper student understanding of the scientific concepts of sire genetics and nutrition interactions in sheep growth

Prenatal and gestational cocaine exposure: Effects on the oxytocin system and social behavior with implications for addiction

Drug abuse during pregnancy is a major public health concern, with negative consequences throughout development. Prenatal cocaine exposure (PCE) in rats produces social behavior deficits with corresponding changes in neuroendocrine and monoaminergic signaling. The relevance of parental care in social behavior maturity cannot be ignored, and gestational exposure to cocaine severely disrupts parental care, thus impacting the early environment of the offspring. Oxytocin (Oxt) is critical in regulating social behaviors and central levels are disrupted following acute and chronic cocaine (CC) treatment in postpartum rat dams, coincident with deficits in maternal care. We will discuss studies aimed to determine the relative contribution of PCE and CC-induced deficits in maternal care to social behaviors and Oxt signaling across development. PCE results in decreased social (including parental) behaviors in adolescence and adulthood. PCE is also associated with increased aggression in adults. Rearing by CC-exposed mothers synergistically increases the behavioral effects of PCE. Rearing by CC-exposed mothers, but not PCE, disrupts Oxt levels and mRNA in regions relevant to social behavior, but does not affect receptors in postpartum adult offspring. Preliminary work indicates PCE/CC rearing has dynamic effects on Oxt levels and receptors in neonatal rat pups, suggesting very early regulation of Oxt signaling. This work highlights how the interactive role of Oxt signaling and behavioral context throughout development can be derailed by drug abuse during pregnancy. The relevance of disrupted Oxt to intergenerational transmission of addiction is briefly discussed