Internal parasites are an ever present factor in livestock operations, although it's easy to forget their negative effects because they are often "out of sight and out of mind." According to the USDA's National Animal Health Monitoring System (NAHMS) data, nearly 40% of all cow-calf operations do not treat their unweaned calves with a dewormer product. This low utilization of parasite control assuredly impacts the overall production of our cattle and decreases their ability to perform.

Performance loss from parasite infections is subtle. We don't typically see overt clinical signs from cattle carrying parasite infections. However, they do continuously rob our animals of optimum performance every day. Worms cause cattle to decrease their feed intake. This lowers weight gain and reduces body condition, potentially leading to lowered reproductive performance, and decreases milk production, causing reduced weaning weights. Internal parasite infections also cause intestinal tissue damage and blood loss, leading to poor nutrient absorption, lowered feed conversion and reduced immune competence. All of these negative effects lead to increased costs to the producer and cause poor productivity.

Knowing that parasites cause substantial economic loss to your operation each year, the next question is, "How much will my calves benefit from controlling worms?" Recent research completed at the University of Arkansas demonstrates the impact of deworming calves prior to weaning. This study was undertaken to compare the performance of calves that received dewormer prior to weaning versus calves that did not receive dewormer. Eighty-seven fall-born beef calves from the University of Arkansas beef cow herd were utilized in this study. Calves had average body weights of 310 pounds and were randomly allocated to treatment groups. The two treatment groups were examined over an 85-day preweaning phase and included: (A) calves injected with Cydectin® at 85 days prior to weaning and (B) a negative control group (Table 1).

Results showed that the calves that were treated during the pre-weaning phase had significantly better average daily gain (ADG) up until weaning when compared to the untreated calves during the same period (1.82 vs. 1.70 lb/day). Average cost of treatment for calves at 85 days prior to weaning was less than $0.90/head, and treated calves would have been worth approximately $13.00 more per head than untreated calves at weaning due to their body weight advantage.

These results indicate the importance of deworming your calves and the impact it can have on gain performance. Current recommendations suggest that producers treat all calves over 220 pounds to improve weaning weights. Always remember to use all products as specified on the label. If you reduce the dose or give the product in a nonindicated fashion, the effectiveness of the product will be diminished. However, utilizing proper deworming practices on your farm will increase your overall productivity and efficiency.

Source: Jeremy Powell, University of Arkansas Division of Agriculture