The effects of preventive measures against neonatal diarrhea and bovine respiratory disease (BRD) on the reproductive and milk production performance of calves in later stages

Abstract

Objective This study aims to investigate the performance parameters of 81 calves raised on a dairy farm, to evaluate the impact of neonatal calf diarrhea and bovine respiratory disease (BRD) on these parameters, and to assess the effectiveness of a preventive nutritional strategy in mitigating the effects of these diseases. Materials and methods Holstein-Friesian crossbreed (HF & times; Montb & eacute;liarde) calves were divided into control (C, n=70) and experimental (E, n=11) groups. In the first phase of the study, the experimental group received a commercial feed additive for 10 days post-birth, while the control group received no additive. All calves were vaccinated against BRD at scheduled intervals. In the second phase, performance parameters were evaluated, including age at insemination resulting in pregnancy (AIRP), pre-pregnancy body weight (PPBW), number of inseminations per pregnancy (NIPP), initial calving body weight (ICBW), age at first calving (AFC), and daily milk yield (MY). The study was conducted over a period of 33 months. Results In the first part of the study, 36 out of 81 animals (44%) experienced illness. Among the affected animals, 28 had diarrhea (including those with both conditions), 23 had respiratory diseases (including those with both conditions), 13 had only diarrhea, 8 had only respiratory diseases, and 15 suffered from both diarrhea and respiratory diseases. Although BRD pathogens were not investigated, rotavirus was identified as the primary cause of diarrhea. Data from the second part of the study revealed statistically significant differences in ICBW, NIPP, and MY between sick (n=36) and healthy (n=45) animals (p<0.05). A statistically significant difference was also observed in average milk yield during lactation among sick animals (p<0.001). The study concluded a significant negative correlation between diseases contracted during the neonatal period and milk yield, indicating that the impact of these diseases on average lactation is substantial (F=19.990; p<0.001). The 2 neonatal diseases significantly reduced average milk yield (beta=-2.144). A history of Cryptosporidium parvum infection was associated with a higher incidence of BRD among affected animals, which also exhibited the lowest milk yield. Performance parameter analysis between control and experimental groups showed statistically significant differences in ICBW and MY (p<0.05). Conversely, PPBW, AIRP, AFC, and NIPP did not differ significantly between groups (p>0.05). Conclusion and clinical relevance The findings indicate that a significant proportion of calves initially presenting with diarrhea subsequently developed bovine respiratory disease (BRD), suggesting a potential association between early enteric disorders and later respiratory complications. This progression negatively impacts neonatal animal health and reduces milk yield, a critical productivity parameter for dairy farms. Consequently, neonatal diseases diminish long-term farm profitability. The results emphasize the benefits of prophylactic measures aimed at reducing diarrhea incidence during the neonatal period. Such strategies may promote healthier, more productive calves, thereby enhancing overall animal health and farm productivity.