24 October 2023

Keeping dairy beef animals healthy this winter

This year’s wet and mild summer has resulted in higher parasitic burdens in dairy beef animals. With housing underway in many parts of the country, it is important to eliminate these burdens to ensure animals remain healthy to optimise performance during the indoor period.

Stomach worms

In dairy beef systems, worms are generally more of an issue in younger stock. However, the presence of stomach worms can be monitored using fecal sampling; if detected, dosing is recommended. Additionally, fecal sampling a few weeks after treatment is good practice to ensure the product used gave an effective treatment.

When choosing a winter housing dose, it is important that all stages of stomach worm are treated. If the product selected does not provide sufficient cover against the larvae stages, they can become dormant over the winter and then reappear as type II ostertagiosis in the spring- causing severe disease in animals.

Yellow drenches, derived from the active ingredient levamisole, are not effective in treating these larvae, whereas clear drenches (macrocyclic lactone) and certain white drenches (benzimidazoles) will provide effective treatment.

Lungworm

Given the wet and mild nature of 2023, it is not surprising that many farmers are reporting a higher incidence of lungworm infections. Monitoring for clinical signs, such as a husky cough or difficult breathing, is the best way to identify if there is an issue.

Heavy infestations can lead to respiratory disease, therefore a pre-housing treatment is recommended to ensure animals are clean of any burden before housing.

As regards treatment and control, most available anthelminthics are effective against larval and adult lungworm. Levamisole and white drenches will take out the parasites present on the day of treatment, but will have no residual affect. Macrocyclic Lactones, such as ivermectins, will give longer protection.

Liver fluke

High levels of rainfall and mild temperatures experienced since turnout have provided the ideal conditions for liver fluke to thrive. Farmers across the country need to assess their own farm situation and take action to deal with any potential issue. Lack of thrive, poor appetite and reduced weight gain are all ill effects of liver fluke, therefore early intervention is necessary.

Once eaten, liver fluke start to feed and grow. It takes approximately 12 weeks for the fluke larvae to grow to adult stage, when they start to lay eggs. These eggs pass out in the faeces of the animal and, when conditions are suitable, they hatch and use the mud snail to continue the life cycle. During this 12 week period, the fluke are classified according to their stage of development:

• First 5-6 weeks – early immature fluke;
• Weeks 6-10/11 – immature fluke;
• Week 11+ – adult fluke.

There are a number of different flukicides on the market, but certain products are only effective against certain stages. Some are only effective against the adult stage, therefore careful consideration needs to be given when deciding what product to use and the timing of the treatment.

If using a product that only treats adult liver fluke, stock need to be in at least 11 weeks to ensure an effective treatment. In areas where burdens are high and farmers need to intervene quickly, triclabendazole-based products which cover all three stages can be given a few weeks post housing. There is some known resistance to this product in certain parts of the county, so precaution is advised.

In other cases, there are a number of products that also effective against mature and immature and these will give an effective treatment if administered six weeks after housing. When selecting a product check the label to check the stages treated. Table 1 below outlines the active ingredients used in the control of liver fluke in cattle and the stages treated.

Table 1: Active ingredients and stages treated

Rumen fluke

Rumen fluke is generally not as severe an issue in dairy beef systems. In faecal tests, the majority of animals may show low levels of rumen fluke present, but treatment is not required unless clinical signs such as scouring and weight loss are evident. Oxyclozanide based treatments are the only doses effective in the treatment of rumen fluke, therefore correct use is required to prevent resistance issues.

Pneumonia

Where previous issues were encountered with pneumonia, a pre-housing vaccination plan should be explored in conjunction with local veterinary advice. There are a range of vaccines currently available, which cover the most common pneumonia causing viruses and bacteria.

Vaccines are available in intranasal form to cover the two most common viral forms – Respiratory Syncytial Virus (RSV) & Parainfluenza type 3 (PI3) – and can be administered to animals pre housing, providing protection from viruses five days after administering with cover lasting up to three months.

Other vaccines are available in injectable form to cover these two viruses as well as a major bacterial pneumonia form – Mannheimia haemolytica. This vaccination programme is two shots four weeks apart, with the initial shot to be administered at least six weeks pre housing. A booster is required at least two weeks pre housing to provide full protection before turn in. Where calves were administered this two shot programme the previous spring, a single shot two weeks pre housing will provide full protection.

Infectious Bovine Rhinotracheitis (IBR)

IBR is another viral disease farmers should be mindful of with outbreaks causing acute inflammation of the upper respiratory tract. Outbreaks can significantly reduce animal performance, resulting in economic losses. The virus can lie dormant in the animal’s system and flare up at times of increased stress, such as housing. There are a number of intranasal and injectable vaccines that are available for IBR and can be administered at the same time as the pneumonia vaccines outlined above.

Good management practises

While vaccines do assist in challenges to animal health, at the same time, no amount of vaccination will overcome a lack of good practices. Factors such as poor ventilation, overcrowding and inadequate parasite control need to be addressed, along with a vaccination programme, to ensure animal performance is not reduced due to pneumonia outbreaks.

Winter herd management online event

The Teagasc DairyBeef 500 team will host a winter herd management online event on Thursday, October 26^th at 8pm, where the contents of this article – along with the feeding and non-feeding factors to consider at housing will be discussed.

Topics and speakers include:

• Health at housing
• Ruminant Veterinary Technical Advisor, MSD Animal Health Ireland
• Areas to be covered include: vaccinations – pre and post housing; parasite control – pre and post housing
• Feeding and non-feeding factors at housing
• Alan Dillon, DairyBeef 500 Campaign Co-ordinator, Teagasc
• Areas to be covered include: feeding levels for different quality silages; non feed factors.

This webinar, which is being hosted on Agriland.ie, will also feature a panel discussion, where the main topics discussed will be expanded upon. The above article was first published as part of the Teagasc Dairy Beef 500 Campaign’s Autumn Beef Series on Agriland.

Also read: Winter management of Gareth Peoples’ DairyBeef 500 farm

Also read: The successful control of liver fluke

Also read: What should you do when you get the IBR test results?

Also read: Controlling lice at housing