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We are currently receiving lots of reports of suspect coccidiosis cases in artificially-reared calves recently turned out to grass.
In this case, the parasite is generally not ‘picked up’ at grass, but already in the animal at turnout. This is particularly true where symptoms occur within three weeks of turning out. It is inevitable that ruminants will pick up coccidia at some point in their lives, in fact we actually want this to happen so that our animals’ natural immunity is stimulated.
There is a difference between coccidia and coccidiosis – the former is an organism and the latter is the effect that the organism has on an animal whose immune system ‘cannot cope’ with coccidia.
Keeping calves free from stress helps their immune systems to develop a strong natural defence, quickly. However, the definition of ‘stress’ is often misunderstood and something as simple as a change in diet or surroundings, without any significant handling, represents a huge stressor for calves.
Calves that exhibit coccidiosis symptoms in the weeks post-turnout will likely have been coping okay with the parasite whilst indoors, and on the way to developing a strong immunity. However, the stress of a new diet and changed surroundings will have weakened their immunity and reduced their ability to cope. This manifests itself as poor thrive across full groups and clinical coccidiosis in the weakest/most stressed individuals.
Full groups should be treated with diclazuril or toltrazuril at, or within 10 days of turnout, on farms that experience coccidiosis in turned-out calves. Ideally our treatment should be timed to be 7-10 days before expected symptoms.
Sometimes coccidiosis is incorrectly cited as being the cause of scours in turned out calves with digestive upsets. A reared calf is a ruminant. Ruminants need and crave effective fibre to stimulate rumen contractions. Typically, calves will receive long fibre such as hay or straw during the housed period, which along with their concentrate ration is critical for their rumen development.
Long fibre
Sometimes, farmers will abruptly turn calves out to paddocks of leafy grass (<10cm), maintain or increase concentrate feeding levels and stop offering long fibre such as hay or straw. This is disastrous from a rumen dynamic/development point of view. This type of grass, and even longer stemmier pasture, is simply not near as effective versus fibre sources like hay or straw at stimulating the rumen. We would expect large proportions of calf groups to exhibit scour symptoms, go off-feed and lose condition in such a scenario.
Yes, an episode like this represents a huge stressor on calves and can also trigger clinical coccidiosis, but the root of the problem here is a nutritional one – a nutritional stressor.
So, when turning calves out to grass, include an effective fibre in their diets until you are happy that they are adept grazers. Include at a rate not more than 15% of dry matter intake and increase concentrate offering slowly, while monitoring faecal consistency. If possible, turn calves out to a paddock with a high pre-grazing height (12cm+) and a high stem content.
Watch the video below and check out these other articles
How soon can animals get coccidiosis?
How does an anti-coccidial drench work?
Coccidiosis effects on dairy heifers
We are currently receiving lots of reports of suspect coccidiosis cases in artificially-reared calves recently turned out to grass.
In this case, the parasite is generally not ‘picked up’ at grass, but already in the animal at turnout. This is particularly true where symptoms occur within three weeks of turning out. It is inevitable that ruminants will pick up coccidia at some point in their lives, in fact we actually want this to happen so that our animals’ natural immunity is stimulated.
There is a difference between coccidia and coccidiosis – the former is an organism and the latter is the effect that the organism has on an animal whose immune system ‘cannot cope’ with coccidia.
Keeping calves free from stress helps their immune systems to develop a strong natural defence, quickly. However, the definition of ‘stress’ is often misunderstood and something as simple as a change in diet or surroundings, without any significant handling, represents a huge stressor for calves.
Calves that exhibit coccidiosis symptoms in the weeks post-turnout will likely have been coping okay with the parasite whilst indoors, and on the way to developing a strong immunity. However, the stress of a new diet and changed surroundings will have weakened their immunity and reduced their ability to cope. This manifests itself as poor thrive across full groups and clinical coccidiosis in the weakest/most stressed individuals.
Full groups should be treated with diclazuril or toltrazuril at, or within 10 days of turnout, on farms that experience coccidiosis in turned-out calves. Ideally our treatment should be timed to be 7-10 days before expected symptoms.
Sometimes coccidiosis is incorrectly cited as being the cause of scours in turned out calves with digestive upsets. A reared calf is a ruminant. Ruminants need and crave effective fibre to stimulate rumen contractions. Typically, calves will receive long fibre such as hay or straw during the housed period, which along with their concentrate ration is critical for their rumen development.
Long fibre
Sometimes, farmers will abruptly turn calves out to paddocks of leafy grass (<10cm), maintain or increase concentrate feeding levels and stop offering long fibre such as hay or straw. This is disastrous from a rumen dynamic/development point of view. This type of grass, and even longer stemmier pasture, is simply not near as effective versus fibre sources like hay or straw at stimulating the rumen. We would expect large proportions of calf groups to exhibit scour symptoms, go off-feed and lose condition in such a scenario.
Yes, an episode like this represents a huge stressor on calves and can also trigger clinical coccidiosis, but the root of the problem here is a nutritional one – a nutritional stressor.
So, when turning calves out to grass, include an effective fibre in their diets until you are happy that they are adept grazers. Include at a rate not more than 15% of dry matter intake and increase concentrate offering slowly, while monitoring faecal consistency. If possible, turn calves out to a paddock with a high pre-grazing height (12cm+) and a high stem content.
Watch the video below and check out these other articles
How soon can animals get coccidiosis?
How does an anti-coccidial drench work?
Coccidiosis effects on dairy heifers