Case-control study on factors associated with a decreased milk yield and a depressed health status of dairy herds in northern Germany.

BACKGROUND: In the past years, it became apparent that health status and performance differ considerably within dairy farms in Northern Germany. In order to obtain clues with respect to possible causes of these differences, a case-control study was performed. Case farms, which showed signs of health and performance problems, and control farms, which had none of these signs, were compared. Risk factors from different areas such as health management, housing, hygiene and nutrition were investigated as these are known to be highly influential. The aim of this study was to identify major factors within these areas that have the strongest association with health and performance problems of dairy herds in Northern Germany. RESULTS: In the final model, a lower energy density in the roughage fraction of the diet, more pens with dirty lying areas and a low ratio of cows per watering spaces were associated with a higher risk for herd health problems. Moreover, case farms were affected by infections with intestinal parasites, lungworms, liver flukes and Johne's Disease numerically more often than control farms. Case farms more often had pens with raised cubicles compared to the deep bedded stalls or straw yards found in control farms. In general, the hygiene of the floors and beddings was worse in case farms. Concerning nutrition, the microbiological and sensory quality of the provided silages was often insufficient, even in control farms. Less roughage was provided to early lactating cows and the feed was pushed to the feeding fence less frequently in case farms than in control farms. CONCLUSIONS: The results show that milk yield and health status were associated with various factors from different areas stressing the importance of all aspects of management for good animal health and performance. Moreover, this study confirmed well-known risk factors for health problems and performance losses. These should better be taken heed of in herd health management.

Understanding barriers to following advice: Evaluation of an advisory service from dairy farmers' perspectives.

In dairy herd health medicine, the success of consultation is sometimes limited as farmers do not always implement given advice. Therefore, the objective of this study was to evaluate a consultation performed during a study in the northwest of Germany and thereby to detect barriers that hinder farmers with long lasting problems in herd health from implementing veterinary advice. Six to twelve months after a non-recurring extensive herd health analysis and consultation, 38 farmers were interviewed by phone. Nearly all farmers were content with the farm visit, and 79% of the farmers stated that they had implemented at least some of the advice. This shows that farmers appreciated this service in general and were willing to follow advice. Even though the results cannot be generalized, factors that could be considered by advisors to improve the success of consultation were detected: Reasons as to why the advice was rejected were mostly related to farmers' expectations. Implementing only some of the advice was caused by a lack of time, self-discipline, money, and a lacking farm successor. Factors that pleased farmers were friendliness of the study veterinarians, in-depth examinations, handling of cows, good advice and how well organized the farm visit was. Factors that displeased the farmers were usually indicated only by one farmer each. Other factors influencing the success of consultation were the teamwork with the practising veterinarian, the self-evaluation of the farmers and the desire of the farmers for a single reason for the herd health problems.

Occurrence of Clostridium botulinum neurotoxin in chronic disease of dairy cows.

Botulism caused by neurotoxins of Clostridium (C.) botulinum is a rare, but serious life-threatening disease in humans and animals. Botulism in livestock is usually caused by the oral uptake of C. botulinum neurotoxins (BoNT) via contaminated feed and is characterized by flaccid paralysis. In the recent past a new syndrome caused by BoNT in dairy cattle was postulated. It was supposed that C. botulinum is able to colonize the lower intestine and may subsequently produce neurotoxin. The continuous resorption of small amounts of these BoNT may then provoke the so called syndrome of "chronic" or "visceral" botulism involving unspecific clinical symptoms, reduced performance of dairy cows and massive animal losses in the affected herd. To test this hypothesis a case-control study was conducted involving 92 affected farms and 47 control farms located in Northern Germany. Fecal samples of 1388 animals were investigated for the presence of BoNT to verify the key requirement of the hypothesis of chronic botulism. BoNT was not detected in any of the fecal samples using the most sensitive standard method for BoNT detection, the mouse bioassay. Therefore, the existence of "chronic" or "visceral" botulism could not be proven.