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Options to limit summer scour in calves

Options to limit summer scour in calves

Some farms have encountered problems with summer scour syndrome in weaned calves over recent years. On this week’s Let’s Talk Dairy Webinar, Teagasc Dairy Specialist Stuart Childs discussed the best practice around weaning and a number of steps farmers can take to limit this syndrome occurring.

“Summer scour syndrome is basically rapid onset of diarrhoea in calves,” Stuart explained, “and calves can get very sick very quickly. To date, there has been no identification of any infectious agent as a cause of it and in some cases it can often be considered to be another disease for a period of time before it is actually diagnosed.”

Along with scouring, calves develop inflammation and scabbing around the mouth, which makes the intake of feed and water difficult and results in rapid weight loss. One suggested cause has been the grazing of calves on lush grasses, which is multiplied by the fact that calves are selective grazers initially and have preference for the best grass within the sward. This creates an environment within the rumen where very low levels of fibre are consumed and causes an acidic nature to develop. In addition to this, another causal factor that has been potentially identified is the weaning of calves with slightly underdeveloped rumens.

To prevent the latter problem occurring, Stuart touched on the key elements to consider with the management of calves. The objective of the milk feeding period, he explained, is to double birth weight by weaning. During this period, the weight gains achieved are critical to ensure growth rates or target weights are achieved in the long term. However, in instances where this target has been achieved, some outbreaks of summer scour have occurred and these may be as a result of this weight gain being achieved from high milk feeding levels or an insufficient intake of concentrates and rumen development prior to weaning being commenced.

When calves are born, Stuart explained, the rumen is quite small and it needs time to be developed, adding: “How we go about that is important. The milk plays an important role in providing the nutrition to the animal in that early stage of life because the rumen isn’t in a position to process any significant quantity of concentrate, hay and straw. Offering starter and fresh water from the first week of life is very important.”

The inclusion of a starter ration encourages the development of rumen papillae – finger like projections within the stomach chamber critical for the absorption of nutrients – which are required by animals in later life to absorb the nutrients created during the breakdown of forage-based feeds. To commence this process, cereal-based rations and water should be offered from the first week of life, building to at least 1kg/head/day at the point of weaning.

Key points:

  • Milk diet most important in early life;
  • Rumen takes time to develop;
  • Offer starter and fresh water (5L of water per kilogram of concentrate fed) from the first week of life to promote rumen development;
  • Pre-weaning diet important;
  • Wean gradually – calves should be eating at least 1kg/head/day of concentrate;
  • Target weaning weights dependent on mature body weight – safe when at 15% of pre-calving weight.

The reduction of stress during the weaning process is also critical and calves must be transitioned correctly from a milk feeding to a forage-based diet to minimise dietary changes and to avoid a post-weaning growth check occurring. He encouraged farmers to evaluate ways of maximising the calf’s intake of concentrates prior to weaning.

“It is important that we wean animals correctly and we don’t do too many changes at the one time. If we change them from twice a day feeding to once a day feeding, we shouldn’t be doing anything dramatic at that stage because it is a stressful period,” he noted. “If you take calves off milk today, they shouldn’t be going out to grass tomorrow. They need an adjustment period again to get them ready for that. Keep them on the concentrate and hay and straw at that stage and then move them onto the grass and keep the straw or hay available.”

Post-weaning options

In circumstances where the correct management procedures are implemented during the milk feeding and weaning transition period, Stuart said it can be disheartening for farmers who still have issues with summer scour occurring. “If we get the weaning piece right, the next piece to deal with is the pasture management,” he added.

There are suggestions that the type of grasses - with very rapid growth rates in April and May – may be contributing to mineral issues similar to what has been seen in dairy cows calves. This, along with the lush nature of very high quality grass may be creating acidic conditions within the rumen, similar to the acidosis seen in animals of high levels of concentrate feeding, while the high levels of nitrogen in the top of the grass plant have also been advanced as a possible cause, along with the low levels of fibre available in periods post-turnout often coinciding with rapid growth in the grass plant.

“The way to manage it is maybe strip graze calves to force them to graze down into the fibre and, as a result, they also create a saliva buffer themselves. Some people have been feeding extra buffer in those [calf] rations and there are different products available in some of the calf rations now to head off or stave off the risk of summer scour. The other option is to go into stronger grass initially and the other suggestions would be that people wouldn’t go to reseeded areas for calves for that early part of the summer in particular, just until they get the chance to develop,” he explained.

The full recording of the webinar in video and podcast format is available below.