Coming into the warmer spring weather, pasture will start to grow, allowing farmers to turn out their weaned calves. Although such freedom is good for the animals from a behavioural point of view, it can cause problems in their gut.
Why Lush Pasture Causes Problems
Fresh, lush rye/clover pasture is high in protein and sugar and low in fibre. During spring growth, levels of protein in these types of pasture can easily exceed 30% on a dry matter basis, or even higher. Ruminants cannot use more than 15% protein in their total daily intake, and any excess affects the control of gas evolution from fermentation. The immature rumen requires long, structural fibre intake to stimulate the developing papillae that provide the surface area and a safe haven for fermentative bacteria on the inner surface. In order to reproduce and colonise the rumen at suitable levels to promote best fermentation, bacteria initially need somewhere to safely reproduce. Establishing the correct balance of microbial populations is essential to the generation of energy and other nutrients and ultimately determines the efficiency of the animal as an adult.
What Is Frothy Bloat?
Bloat is a condition whereby gas produced from rumen fermentation becomes trapped and fails to coalesce to allow safe eructation (burping) – an essential part of rumen function to prevent build up and distension. When protein intakes are high and fibre is low, as in lush spring pasture, bloat occurs, where gas bubbles are held in the rumen in a film of soluble proteins. As an analogy, when brewing, soluble proteins and other compounds as a foamy scum can rise to the surface, effectively making a viscous ‘blanket’ which holds down the rest of the liquid and the gas, until it erupts violently.
The condition called ‘foamy’ or ‘frothy’ bloat in calves is where high levels of soluble proteins, fibre and saponins from lush pasture form around the bubbles from fermentation, holding gas in the rumen. Normally, saliva acts like a detergent to break up these strong films, releasing the surface tension to allow the gas to escape. Young animals do not produce much saliva, hence, the foamy bubbles increase to a point where it causes distention and pain. Longer, high fibre forage, such as hay or straw, can help pierce the bubbles as they form.
Other feeds used alongside fresh pasture can ameliorate bloat conditions. Forage and feedstuffs, such as ground grain or fibre, can help disrupt bubble formation. The fine particle size of milled feedstuffs can break the film of the bubbles. Whole grain feeding does not have the same benefits as milled cereals, and, indeed, there is a phenomenon called ‘feed-lot bloat’ where high levels of starch from the grain promote acid conditions and fast gas production that the animal then struggles to release. So, if farmers are feeding whole grain, care needs to be taken to balance the starch with continuous intake of long, structural fibre. Added oil in the diet will reduce the surface tension of the film holding the bubbles in place, releasing the gas so it can be harmlessly eructated. Indeed, tubed infusion of oil into the rumen is a treatment for clinical bloat. So, suitable dietary intervention can help avoid bloat in calves. Maintaining access to long, high fibre forage as well as a balanced milled feed to ensure rumen development and correct functioning. Where lush pasture is available, putting out bales of hay or straw allow the animals to ‘self-medicate’ by fibre intake (which they normally will do voluntarily), which reduces any symptoms of bloat.
To protect calves from bloat during the lush spring flush, support their developing rumens with the right balance of fibre and processed feed. It’s a small effort that can prevent a big problem.
Talk to your local Reid’s Dairy Specialist today about the benefits of our mash and the products we can offer to suit your requirements on 1300 REID FEED or enquire here >
Author
Dr Lucy Waldron
Head of Nutrition and Technical Services
