Drenching

Internal parasites or ‘worms’ impact significantly on the production efficiency of cattle herds, causing disease, reducing growth rates and sometimes causing death. Internal parasites include tapeworms (cestodes), roundworms (nematodes) and flukes (trematodes). Liver fluke and roundworms cause the biggest problems for producers. 

If internal parasites are not managed properly they can cause substantial economic losses. They can impact animal productivity by causing:  

·      · Severe scouring 

·      · Ill-thrift 

·      · Reduced growth rates 

·      · Loss of weight 

·      · Rough coat 

·      · Poor milk production 

·      · Can cause swelling of fluid under the jaw (“bottlejaw”) 

·      · Increased risk of death

Although there are many different species of roundworms which can infect cattle, their lifecycles are similar. Female worms lay eggs that are excreted in the manure, which then hatch and develop into infective larvae living in the manure. This is known as the first-stage larvae. The larvae then continue to feed on the bacteria in the manure, growing and moulting into second-stage larvae 

The larvae then emerge from the manure onto pasture and are therefore able to infect cattle when ingested with the pasture. This is known as third-stage or infective larvae (L3) or the parasitic stage once the larvae becomes ingested. Adult worm then develop in the abomasum (4th stomach) becoming fourth- stage larvae (L4). Development of larvae into adult worms usually occurs within 3 weeks following ingestion. 

Producers should utilise both ‘chemical’ and ‘non-chemical’ options when developing an approach to worm control. ‘Non- chemical’ approaches include providing adequate nutrition and low risk pastures for young cattle. Chemical approaches include the use of drench. 

Animals that are provided with adequate nutrition are able to cope with worm burdens better. They are better able to endure the symptoms of worms, increasing the rate of recovery. Grazing cattle, particularly young stock, on lower risk pastures will enhance the efficacy of drenching. 

These pastures include 

·      · Pastures which have been rotationally grazed between sheep and cattle. Worms are generally host-specific. 

·      · Pastures that have not been previously grazed by any 

cattle for at least 4 months. 

·      · Newly sown pastures 

- Drenching for worms -

There are three groups of drenches commercially available for the treatment of worms. Application varies from pour-on, injection and oral drench and may impact the effectiveness of the drench. It is important when selecting a drench that particular attention is paid to storage and handling instructions, dosage requirements and withholding periods and export slaughter interval. 

If you have any concerns or questions on the frequency of drenching – (we do advise twice yearly) please contact the veterinarian to discuss an adequate plan to help protect your herd.