Dr Gareth Kelly

Veterinary Medical Services - Boehringer Ingelheim Animal Health

Calves and pasture consumption

Un-weaned Angus calves, from about one month of age to 6 months of age, obtain over 50% of the energy they require for growth from pasture.¹ While pasture quality and quantity is extremely important for calf growth, other factors, such as internal parasites, can have negative effects on growth.

Pastures and worm challenge to calves

Worm larvae on pasture builds up during lactation. Grazing cows have been shown to have increased worm egg counts at calving². As young calves develop and consume more pasture, it exposes them to the infective worm larvae, which live on the pasture. Both calves and the cows that are infected with worms will contribute more worm eggs to the paddock, which increases the worm burden in the cattle. Pastures with cow-calf units can carry a significant worm challenge.

Worm challenge and liveweight gain

Young cattle have limited immunity to diseases and parasites, and likely to be in an environment suitable for high parasite challenge. This challenge can have significant effects on liveweight gain, with most production loss caused within 6 months of weaning³.

To prepare better for weaner sales, consider the following:

1. Consider earlier weaning: Beef cows are also more likely to convert increased pasture intake to body condition rather than increased milk output. High quality pastures can be better utilised fed directly to the calf.
2. Prepare clean pastures for weaners: Cleaner pastures can be prepared by grazing paddocks with sheep or cattle older than 18 months for 6 months, prior to grazing weaners.
3. Treat cattle for parasites: Removing worm infections in young stock can improve weight gain. Due to drench resistance, single active drenches may not be the most suitable treatment in young cattle. Drenching with Eclipse Combination Pour-On has been shown to increase liveweight gain compared to using single active drenches⁴. If cattle are to be slaughtered within 56 days of treatment for the domestic market, or 70 days for export, Eprinex provides a convenient alternative.

1. Roca Fraga, F.J., et al (2018) Intake of milk and pasture and growth rate of calves reared by cows with high or low potential for milk production. Animal Production Science, 58, 523-529. 2. Perri, A.F., et al. (2011) Gastrointestinal parasites presence during the peripartum decreases total milk production in grazing dairy Holstein cows. Vet Parasitol, 178(3-4), 311-8. 3. Watt, B., et al., The Cost of Internal Parasites in Young Cattle on the Central Tablelands of NSW, in AVA Annual Conference. 2011: Adelaide. p. E3.6.1  4. Allworth, M.B., et al. A comparison of the effectiveness of a single active macrocyclic lactone drench with an abamectin/levamisole combination drench, and the effect on weight gains, in beef cattle in southern New South Wales. In: Australian Society of Animal Production. 2018. Wagga Wagga.