Morbidity and mortality in Holstein calves from birth to 145 days of age on a large dairy farm in Brazil

Abstract

The present study aimed to investigate the morbidity and mortality associated with the most common diseases during the rearing period of Holstein calves in a high-production dairy farm. The calves (n = 600) were allocated to three groups based on age: G1 (1-7 days, n = 216), G2 (30-40 days, n = 188), and G3 (69-85 days, n = 196). They were evaluated over 60 days at eight different times. The morbidity rates were 47.67% (286/600) for diarrhea, 73.00% (438/600) for bovine respiratory disease (BRD), and 3.83% (23/600) for umbilical inflammation (UI). The mortality rate was 2.33% (14/600) for all the animals studied. The morbidity differed in the groups, with higher rates of diarrhea (78.85%, 166/216) and UI (6.94%, 15/216) in G1, and the highest rate of BRD in G3 (79.59%, 156/196). Diarrhea was associated with the occurrence of BRD in G1 and G2. Even in farms with good management practices, there is high morbidity associated with diarrhea and BRD, with the morbidity rate for diarrhea decreasing and that for BRD increasing as the animals get older. In addition, diarrhea is an important risk factor for BRD, especially in younger animals.

Diagnostic accuracy of Wisconsin and California scoring systems to detect bovine respiratory disease in preweaning dairy calves under subtropical environmental conditions

“…With this new method of classification, the prevalence of positive results for WISC for all farms was 30% (145/482). This prevalence is lower than the frequency of 73% (438/600) observed in our previous research, in which a positive WISC was defined by a total respiratory score ≥4, which included suspect and positive animals (Gomes et al, 2021). This apparent difference in prevalence reported by the same research team in the same country demonstrates the importance of clinical score definition on estimates of disease prevalence.…”

“…Evaluation of these data indicated that the rectal temperature was the main parameter responsible for the positive Wisconsin score when the initial classification proposed by McGuirk (2008) was used, in which a positive score was defined as a total score of 5 or greater. In this previous research, the distribution of rectal temperatures according to the Wisconsin score was (number and percentage of total): 679 (13.57%), 1,738 (34.75%), 2,258 (45.15%), and 326 (6.51%) from a total of 5,001 observations, for scores of 3, 2, 1, and 0, respectively (Gomes et al, 2021). Based on these previous results, we formulated the hypothesis that the relatively high temperatures seen in calves could be related to differences in environmental conditions and weather in tropical or subtropical countries versus Wisconsin, and that this could invalidate the use of the Wisconsin scoring system or the California scoring system, which was developed based on the Wisconsin system.…”

“…High BRD prevalence has been detected in subtropical and tropical countries (Gomes et al, 2021), which may be related to higher environmental temperatures and humidity, leading to increased rectal temperatures that could be interpreted as fever, therefore, contributing to incorrect BRD diagnosis. For this reason, our hypothesis was that the accuracy of the clinical scoring systems developed in the United States could be different in tropical conditions.…”