A Practical approach to the diagnosis of a dairy herd problem

A case report

Abstract

A 390 cow dairy presented in August of 1994 with a complaint of chronic respiratory disease in their milking herd. The history involved numerous management changes over the previous 2 years, including 3 changes in nutritionists, purchase of 37 new heifers from 2 outside sources and construction of a new milking parlor. An investigation of the herd established that the rolling herd average had declined nearly 6000 lb in the previous year and a half. The dairy had a cumulative incidence of cystic ovaries in a 3 month cohort of cows of 46% and body condition scores were well below desirable goals for the whole herd. The major problems of decreased milk production and loss of body condition were the focus of the investigation. Although the total mixed ration formulation calculated and recommended by the current nutritionist was deemed to be adequately balanced for each milking string, analysis of the cow rations revealed an energy deficit of 6.03 Mcal/cow/day for the top milking string and comparable deficits for the lower strings. It was discovered that the auger used to meter out grain for the total mixed ration was miscalibrated. The auger was delivering 22% less grain into the ration than was believed. The producer had the auger calibrated to correct the problem. A follow up investigation was done nearly 2 years later, in May of 1996, to evaluate the changes in milk production, services per conception, body condition scores and other parameters over a 6 year period. Both rolling herd average and body conditions had improved markedly from the time of the original investigation. This case was used as a general example of how to approach the diagnosis of a herd problem.