Nutrition for dairy cows in the lead up to calving
Nutrition during the dry period plays an important role in preventing potentially serious problems in the pre-calving, calving and post calving period. Diseases like pregnancy toxaemia, milk fever, left and right displaced abomasums (twisted gut), retained membranes, lactic acidosis, ketosis, fat cow syndrome (fatty liver), and resulting downer cow syndrome can all be contributed to poor nutrition.
The trick is to prevent pregnant cattle from becoming fat during the last trimester of pregnancy, particularly during the dry period. During pregnancy cattle should receive sufficient feed to meet the needs of the cow and pregnancy, and the total daily nutrient intake must increase throughout the last trimester to meet the needs of the fetus. Feeding of predominantly hay/roughage to extent is a reliable milk fever preventative.
Adding anionic salts to the diet in the late dry period is an important part of the transition diet. These salts such as magnesium sulphate, calcium sulphate, and ammonium sulphate acidify the cow’s diet, which promotes the absorption of calcium from bone and the gut. When the bone is already in a mobilization phase at calving, the cow is better able to respond to the sudden calcium demands at the start of lactation and therefore less likely to develop milk fever. Studies have also shown that feeding these anionic salts precalving increased milk production in early lactation, results in less disease, and increases subsequent fertility. Anionic salts need to be fed for at least 10 days before calving to have any effect but should be fed longer than this (20 days).
The problem with anionic salts is that cows don’t like the taste of them, and so they should be fed into a total mixed ration. There are now many anionic salt additive pellets commercially available from feed suppliers. If you feed anionic salts mixed with grain it is important that the grain does not contain a buffer such as sodium bicarbonate since buffers counteract the acidifying effect of the anionic salts.
An alternative is the use of magnesium sulphate (epsom salts) added to drinking water as an anionic salt with reasonable success. A dose of 100-150 grams of Epsom salts added to the water trough per cow per day is needed. To work it must be added to the sole available water supply.
For further information on lead feeding, please contact Main Street Vets. Stock feed suppliers stock the necessary additives for the feed, and can also give advice.