You notice a calf lying down and kicking at its belly, back up and running, then dropping down and kicking again. Suspecting a serious problem, you get him in but in an hour he is back to normal. What about the beautiful six-week-old calf – fat and healthy – that you found dead in the field? A post-mortem revealed a ruptured abomasum with stomach contents floating in the abdomen. What is happening?
The digestive system of a calf undergoes a remarkable transformation. As a nursing calf, the milk basically goes straight to its fourth stomach (the abomasum) by means of an extraordinary structure known as the esophageal grove. The rumen of the calf, very small at first, begins to develop at three to four days of age as the calf starts to consume bits of roughage and picks up bacteria and protozoa from licking the ground and manure.
In the next few months the calf matures to a ruminant: a cud-chewing, gas-passing adult that can digest plant material that many other species cannot. A mature bovine or ruminant relies on the forestomachs, basically large outpockets of the esophagus, for predigestion. In the first and second forestomachs (the rumen and reticulum), feed breakdown occurs because of the complex integration of ruminal movements, saliva, bacterial and protozoal action, gas expulsion and chewing of regurgitated feed. The partially-digested feed is then moved through the third stomach, the omasum, where water is removed, to the abomasum where true digestion occurs. The abomasum, similar to our stomach, has digestive enzymes and acid.
It is during the period of transformation, as the calf moves from a milk-based diet to a ruminant animal, that many of the problems occur. Painful abdominal disorders in a young calf less than two months old can be difficult to distinguish from one another. Your veterinarian will do a physical exam, assess the signs the calf is showing and consider the age of the calf and the speed of onset of the signs Obtaining the diagnosis can be a challenge as many disorders present a similar picture. Your veterinarian will discuss the options for treatment with you, including the option of surgery.
The most common abdominal disease in calves less than one week with abdominal distention is atresia coli. A segment of the colon does not develop a lumen (or opening) in the center and the digesta hits a blind spot. The calf cannot produce manure — only traces of muconium, blood and mucus. Although surgery is possible it is usually not recommended or economical.
Other causes of colic in very young calves are atresi ani (no anus or rectum), navel infections, scours and infection in the abdomen (peritonitis) and occasionally torsion.
What about the older calf with pain that resolves on its own or with minor medical treatments? Most likely these are due to gas and diet-related. Gas can form from bacterial proliferation from poorly digested food, possibly over-consumption of milk. The gas could be in the abomasum or further down the digestive tract. Occasionally the gas production may result in abdominal displacement or torsion. Intestinal torsions, intussusceptions (telescoping of the intestines) and foreign bodies will also need surgical correction. The clinical signs of these problems are variable and the decision to do surgery can be a difficult one: exploratory surgery can diagnose the problem, but the outcome may be difficult to predict.
The great-looking calf that died? Abomasal ulceration was found at postmortem. The cause is unknown. It likely had multiple problems, possibly to do with forestomach development. Other contributing factors could be mineral deficiencies, clostridial bacteria, abrasive agents and stress.
Some farms have seen an apparent decrease in numbers of ulcers by vaccinating the cows prior to calving with a clostridial (blackleg) vaccine. Hairballs are often found on postmortem in calves with ulcers but they are found in a similar number in calves without ulcers. There is no evidence to suggest they are causing the ulcer or the abomasal disease.
You have a great crop of calves. Your veterinarian is a great resource in helping you keep them alive!