Digestive challenges in calves
By Siobhan Regan – Veterinary Technical Advisor at AHV UK & Ireland
Every dairy farmer has to deal with digestive challenges in calves. This is – unfortunately – a common challenge on-farm. As a result of these challenges, calves may have impaired growth and for the farmer it means lots of work and costs caused by potential value and money loss. As an example, the cost for a calf with digestive challenges can go as high as €75 per calf on average. In addition, other costs must also be taken into account: extra rearing costs, weight loss and extra labour. Due to this growth delay of the calves, insemination at later age becomes a direct cause for increased rearing cost. In addition, this heifer will also produce less in the first lactation, compared to a healthy calf without digestive challenges.
Causes of digestive challenges
The cause for digestive challenges varies from farm to farm, but it is often a combination of factors as well. Digestive challenges can be of different origins. One cause includes unfavourable bacteria. In the case of other causes, consider disturbed protein or fat digestion and/or poor environmental hygiene. Digestive challenges caused by bacteria can result in a damaged intestinal wall. Reason for this are unfavourable bacteria at gut level affecting the intestinal epithelial cells. As a result, the intestinal surface area decreases reducing the ability to absorb nutrients. These calves are therefore prone to having reduced growth rates. This challenge concerning the intestines is illustrated in figure 1.
Figure 1: Intestinal wall lining(1).
Normal gut village(2), responsible for surface area enlargement are irreparably destroyed or made impenetrable due to scarring by unfavourable bacteria(3).
Measures for a proactive approach
A number of factors play a major role in taking a proactive approach for digestive challenges in calves:
Hygiene and housing
It is important to ensure that calves are born in a clean environment. After calving, calves can come into direct contact with bacteria from the environment, which can eventually cause digestive challenges. The calves ingest these bacteria, after which they end up in the intestines and can cause challenges. A proper environment after birth means that the calf is placed in cleaned, dry pen with a sufficiently thick layer of straw. This thick layer of straw ensures that the calf can create its own microclimate that safeguards it from environmental influence.
The importance of colostrum
After the calf has been housed, the most important thing comes into play: the first colostrum. Optimally, calves must have ingested 200 grams of immunoglobulins within 6 hours of birth. Immunoglobulins are antibodies, determining the extent of the animal’s resistance. Therefore, each litre of colostrum should contain 50 grams of immunoglobulins which allows for a calf to reach the aforementioned value with 4 litres of colostrum uptake. For this, the so-called Brix-value of the colostrum, which can be measured using a refractometer, must be at least 23.
The calf must ingest this amount within 6 hours after birth to allow for absorption of antibodies through the intestinal wall. Shortly after birth, the absorption capacity is 100 percent, but after 6 hours it is already halved. The first ‘obtained’ resistance of the calf is completely via the colostrum. If the calf cannot make use of this resistance, by, for example, a low number of antibodies in the colostrum, the calf may be more prone to digestive challenges early on. The very first step to tackle digestive challenges is therefore to always quickly provide a good quality and quantity of colostrum.
Supporting the development of the immune system
In addition to the first colostrum feeding, it is equally important to support calves during the first weeks of life. The first 2 weeks are particularly critical for the calf. The obtained resistance from the colostrum is slowly lost and calves have to build up and acquire their own immune system. In these 2 weeks, calves are therefore especially sensitive to digestive challenges. Just like after birth, hygiene during the rearing period should be guaranteed. To achieve this, pens must be cleaned and disinfected, farm boots and overalls, drinking materials should be clean and of good quality. In addition to this, it is also important to work correctly with the right drinking materials(like the milk feeder or bucket teat), and to ensure the correct preparation of the milk and milk replacer.
Providing milk and milk replacer
If milk or the milk replacer are not properly prepared or when damaged or incorrectly attached drinking materials are used, the calf’s oesophageal reflex may not work properly, and the milk ends up in the calf’s developing rumen instead of the abomasum. Normally, a fold in the stomach, called the oesophageal groove, allows for milk to bypass the rumen when the calf drinks. However, when a calf does not have the correct drinking position, or when the teat is of poor quality, the milk not at the right temperature or has an incorrect composition, this system will not work optimally. As a result, milk will flow into the rumen. Once in the rumen, milk cannot be properly digested and will subsequently ferment and rot, potentially leading to a calf having to deal with digestive challenges. With regards to teat quality, the quality of drinking teats should be checked; they should not be broken, ruptured or otherwise compromised and should be place in the right position and at the right height. The correct position of the teats is illustrated in figure 2.
Figure 2: Teat position.
The correct way of positioning the teats, in a ‘+’ shape allows for proper milk flow. An ‘x’ shape hinders or blocks milk flow.
The teat should be in a ‘+’ shape to allow for a proper flow of milk out of the teat. In contrast, when placed in an ‘x’ shape, milk flow is blocked or hindered. If not properly monitored, it could then appear that a calf is not drinking and is suspected of having underlying health challenges, whilst in reality it’s being underfed. In addition, bad quality teats can lead to air sucking, also impairing the oesophageal reflex, once again resulting in milk to end up in the rumen.
After the milk feeding period, weaning is best done gradually to avoid calves from getting into a weaning dip. During and after weaning, calves gradually learn to process roughage as milk provision is gradually reduced. During the milk feeding period, thanks to providing quantities of solid feed, the rumen can already slowly develop, to further mitigate a potential weaning dip. In case of a weaning dip, growth may be impaired or even completely stagnated, hence it is worthwhile avoiding this as much as possible.
Would you like to know more about this topic and how AHV can support you and your herd? Please fill in the form below or contact your local farm advisor directly.
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