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.

Weaning

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.