Short communication: On recognizing the proper experimental unit in animal studies in the dairy sciences.

Sound design of experiments combined with proper implementation of appropriate statistical methods for data analysis are critical for producing meaningful scientific results that are both replicable and reproducible. This communication addresses specific aspects of design and analysis of experiments relevant to the dairy sciences and, in so doing, responds to recent concerns raised in a letter to the editor of the Journal of Dairy Science regarding journal policy for research publications on pen-based animal studies. We further elaborate on points raised, rectify interpretation of important concepts, and show how aspects of statistical inference and elicitation of research conclusions are affected.

Meta-analysis of the effects of sometribove zinc suspension on the production and health of lactating dairy cows.

Objective: To provide an updated evaluation of the efficacy and safety of sometribove zinc suspension (rbST-Zn), a form of recombinant bovine somatotropin, in lactating dairy cows.

Design: Meta-analysis.

Sample: 26 studies published in peer-reviewed journals or reviewed by a regulatory agency.