The effect of dry period duration and dietary energy density on milk production, bioenergetic status and postpartum ovarian function in Holstein-Friesian dairy cows

Peer-reviewed.This is the author’s version of a work that was accepted for publication in Journal of Dairy Science. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Dairy Science, 92(12), Dec 2009. DOI: 10.3168/jds.2009-2374Following parturition, it is typical for dairy cows to enter a period of negative energy balance (NEB) and body condition loss to support mammary milk synthesis, and this is associated with compromised reproductive performance. Alternative management strategies during the prepartum (dry) and early post partum periods may ameliorate this. Forty mature Holstein-Friesian cows were assigned to one of two dry period treatments (standard 8 week dry period (SDP) or no planned dry period (NDP)) and one of two dietary energy density treatments (standard TMR (STMR) or high quality TMR (HTMR)). Milk yield during weeks 1 to 12 postpartum was reduced (P = 0.01) in cows assigned to the NDP treatment. Energy balance (P < 0.001) and body condition score (P = 0.07) during weeks 1 to 4 postpartum were increased in cows assigned to the NDP treatment compared to the cows assigned to the SDP, and BCS increased (P<0.001) from weeks 5 to 12 postpartum in the NDP cows compared to the SDP cows. During the first 12 weeks postpartum, cows assigned to the HTMR had greater (P = 0.02) milk yields and reduced (P < 0.001) milk fat concentration compared to the cows assigned the STMR diet. BCS was greater (P = 0.01) from weeks 5 to 12 postpartum in HTMR cows compared to STMR cows. During the period from weeks -3 to +3 relative to parturition, circulating concentrations of insulin (P = 0.001), glucose (P < 0.001) and IGF-I (P = 0.004) were greater in cows on the NDP treatment compared to cows on the SDP treatment. Cows assigned to the HTMR had greater circulating insulin (P = 0.04) and glucose (P = 0.001) concentrations compared to the STMR cows from weeks -3 to +3 relative to parturition. The first postpartum ovulation occurred earlier for cows on the NDP treatment compared to cows on the SDP treatment (16.9 vs. 24.8 days postpartum; P = 0.02). Cows assigned to the STMR tended to have a higher conception rate to first service (P = 0.07) compared to cows assigned to the HTMR. Energy balance and metabolic status can be improved by either eliminating the dry period or by feeding a higher energy diet, but effects on the reproductive axis appear to be different

The effect of strain of Holstein-Friesian cow on size of ovarian structures, periovulatory circulating steroid concentrations, and embryo quality following superovulation

Peer-reviewedThis is the author’s version of a work that was accepted for publication in Theriogenology. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Theriogenology, 70(7), Oct. 2008, DOI: 10.1016/j.theriogenology.2008.06.030When managed under grass-based systems of production, the NZ strain of Holstein-Friesian cow has superior reproductive performance compared to the NA strain despite having similar SCM yields. This study compared the ontogeny of early pregnancy events in NZ and NA cows. Ten NZ and 10 NA cows were submitted to a superovulation protocol on three occasions. Blood samples were collected daily from every cow from day -3 to +7 relative to a synchronised oestrus during each superovulation protocol. Pre-ovulatory oestradiol concentrations, follicle diameter, post-ovulatory progesterone concentrations, CL diameter, and circulating insulin-like growth factor-I concentrations did not differ between the two strains. Uteri were non-surgically flushed 7 d post AI, embryos were isolated and graded. The proportion of transferable embryos recovered was higher (P<0.01) in the NZ cows compared with the NA cows. A greater (P=0.01) proportion of the recovered structures were at the blastocyst stage in the NZ cows. Peak SCM yield and BCS at the time of peak SCM yield were not different between strains. However during the experimental period the NA cows maintained significantly higher daily SCM yields, whereas the NZ cows replenished significantly greater levels of BCS. The results indicate that differences in periovulatory steroid concentrations and size of ovarian structures do not explain the differences in embryo quality between the two strains. However, strain differences in nutrient partitioning from the time of peak SCM yield through late lactation may provide the key signals responsible for superior embryo quality in NZ cows

Diversity in news recommendation:Manifesto from Dagstuhl Perspectives Workshop 19482

News diversity in the media has for a long time been a foundational and uncontested basis for ensuring that the communicative needs of individuals and society at large are met. Today, people increasingly rely on online content and recommender systems to consume information challenging the traditional concept of news diversity. In addition, the very concept of diversity, which differs between disciplines, will need to be re-evaluated requiring an interdisciplinary investigation, which requires a new level of mutual cooperation between computer scientists, social scientists, and legal scholars. Based on the outcome of a interdisciplinary workshop, we have the following recommendations, directed at researchers, funders, legislators, regulators, and the media industry: - Conduct interdisciplinary research on news recommenders and diversity. - Create a safe harbor for academic research with industry data. - Strengthen the role of public values in news recommenders. - Create a meaningful governance framework for news recommenders. - Fund a joint lab to spearhead the needed interdisciplinary research, boost practical innovation, develop reference solutions, and transfer insights into practice