Fernando Diaz
The preweaning period is the most important phase in the productive lifetime of a dairy cow. Two metaanalyses published recently in the Journal of Dairy Science determined the relationships between early-life parameters and the performance of first-lactation (primiparous) cows. A metaanalysis is the statistical procedure for combining data from multiple studies.
The first meta-analysis included data from 2,880 Holstein calves from 37 calf research trials conducted at the University of Minnesota Southern Research and Outreach Center. The researchers (Chester-Jones et al., 2017) found that average daily gain (ADG) during the first 8 weeks of calf life significantly improved 305-days milk yield in the first lactation: for every kg of ADG at 8 weeks, milk yield improved by 579 kg.
Similarly, in the second meta-analysis (including 21 treatment groups) carried out by Pennsylvania State University’s researchers (Gelsinger et al., 2016) found: for each additional 100 g of preweaning ADG; milk, fat, and protein production during first lactation increased by 130.4, 6.1, and 4.7 kg, respectively.
Continue reading this article published in International Dairy Topics.
