Monitor for late-season parasitic disease in heifers

12 Aug 2019

Producers are being urged to monitor young stock for parasitic infection as the grazing seasons progresses into autumn, to prevent costly production losses.

First- and second-season grazing cattle are at highest risk because they will lack sufficient immunity to prevent disease in the face of challenge from gutworms.

Growth rate

Infection by the gutworm (Ostertagia ostertagi) slows growth in young animals by reducing the time they spend grazing and the volume of grass ingested.

“Losses in liveweight gain due to poor parasite control during a heifer’s first grazing season will not be recouped during the second year at grass, so it’s important to get it right,” says Boehringer Ingelheim Animal Health’s Sioned Timothy.

Parasite control

“A high worm challenge increases the time it takes for heifers to reach puberty. Aiming for calving at 24 months requires attention to parasite control.

“Parasites left untreated can have a significant impact on the long-term productivity of dairy cattle, including impaired fertility, reduced milk yield, and reduced lifetime lactations. Starting parasite control in an animal’s first season at grass will set her up well for a productive life.”

Target liveweights

Regularly weighing young stock to monitor target liveweights can provide a good indication of whether a parasite challenge is affecting growth. Pooled faecal egg counts of grazing young stock can also identify if the group is experiencing parasite challenge.

“It’s neither necessary or advisable to treat the entire group,” says Ms Timothy. “Individual animals should be targeted according to their performance against weight gain targets. This is important for sustainable worm control and reducing the risk of resistance developing.”

Control plan

Producers should consult their vet or local animal health advisor for advice on parasite control plans and diagnostic testing in young stock.