Abstract #225

# 225
Effectiveness of DHIA herd testing frequency on management decisions and dairy herd performance.
Lauren E. G. Clemency*1, Kasimu Ingawa1, Steven Washburn1, John Clay1, Shannon Davidson1, 1North Carolina State University, Raleigh, NC.

Statistical analyses indicate that more data points usually improve the reliability of results; hence the objective of this study is to test the hypothesis that higher testing frequency of a dairy herd by Dairy Herd Improvement Associations (DHIA) affects management decisions and herd performance. Higher frequency of DHIA testing provides more information that can be used to make management decisions, thereby enhancing the decision making process; consequently, resulting in improved dairy herd performance. DHIAs are a farmer-owned organizations originating in 1905 as Newaygo Dairy Testing Association, the first Cow Testing Association (CTA) in the US; it assumed its current name, Dairy Herd Improvement Association in 1927. Throughout its more than 100-year history, the core focus of DHIA has not changed from being the means for dairy cattle genetics improvement in the United States. Basically, dairy farm data are periodically collected on each cow and processed into reports which dairy farmers use to manage their herds. Such records include milk and fat weights, percent butterfat, milk fat price, reproduction parameters, weights of different roughages and grains fed, etc. Values of performance variables are computed to determine periodic profits or losses for each cow in the herd. The National DHIA reports a declining trend in DHIA dairy herd testing participation in the last 11 years; in 2004, about 25,077 dairy herds were on test compared with 17,875 as of 1/1/2015. However, number of dairy cows on DHIA test increased during the same period which indicates shrinking number of dairy farms but an increase in dairy farm size. The report also indicates the Holstein breed to be the predominant breed of DHIA testing. A preliminary study by Minnesota DHIA indicated a production increase resulted from a higher frequency of DHIA dairy herd testing, however, variation due to management approach was not considered. In this study, higher frequency of dairy herd DHIA testing resulted in more valuable herd management information and that management approach should be considered when analyzing how the information should be used to manage dairy herds.

Key Words: DHIA, testing, reports