Transition feeding

The main objective with transition feeding is to maximise feed intake in early lactation through improved health and appetite. The following advantages can be achieved with a good transition feeding program

• Higher and earlier peak production resulting in greater milk production over the whole lactation.
• Reduced weight loss.
• Improved conception rates.
• Less metabolic disorders, lower veterinary expenses and fewer cow losses.
• Less stress for farm operators over calving.
• Improved pasture utilisation with the associated reduction in feed costs.

PRE-CALVING DIET

• Grass hay with low potassium levels fed ad lib.
• Limited pasture (less then 2kg / day).
• 2 – 3kg of Lead-up pellets containing anionic salts for a minimum of 2 weeks prior to calving.
• Unrestricted access to clean water.

Function:

• Because Hay is low in nutrients large volumes are needed to meet the cow’s energy requirements this keeps the rumen distended, which maintains the rumen capacity allowing higher intakes after calving and also reduces the risk of a displaced abomasum.
• Hay and straw require more chewing, the increased saliva production causes break down of bone to provide bicarbonate, freeing up calcium in the process.
• Pasture should be limited for springing cows. Pasture is cationic due to high levels of potassium and rumen digestible protein, this works against the anionic state we are trying to achieve in the springing cow. Pasture also requires less chewing and has less of a filling effect than hay.
• Pellets ferment to volatile fatty acids in the rumen. These acids stimulate an increase in the surface area of the rumen, which is required to absorb the higher concentration of nutrients that will be available in the post calving diet.
• The rumen microbes become adapted to pellets, reducing the risk of acidosis and improving feed utilisation in early lactation.
• Anionic salts increase the mobilisation of calcium from bone reducing the risk of milkfever and the associated depression of appetite.
• Unrestricted access to clean Water is critical to maintain the high intakes of dry feeds required in a pre- calving diet.
• Sufficient feed area, if all cows cannot get equal access to feed timid cows and heifers will not eat to appetite predisposing them to low appetites and metabolic problems post calving.  

Signs of sub clinical Milkfever:

• Most herds suffer some sub clinical hypocalcemia even if no cows actually go down with milk fever.
• Low calcium levels in the blood reduce muscle control. This can lead to difficult calvings, retained afterbirth, displaced abomasum, and mastitis.
• The muscles of the digestive tract are also affected. The reduced intake of feed can result in acidosis, ketosis and a weakened immune system.

Dietary Cation Anion Balance (DCAB):

• To stimulate the release of calcium from bone the pre-calving diet must have a slightly acidifying effect this is referred to as a negative DCAB.
• DCAB is the sum of the alkaline cations minus the acid anions in the feed.
• A good indicator of the diet being sufficiently anionic is urine pH. The average urine pH of Holsteins should drop to between 6 and 6.8 and Jerseys to between 5.8 and 6.5.
• If pH drops below these levels the diet is too acid and feed intake will fall.

POST-CALVING DIET

Transition feeding covers the period 3 weeks either side of calving, it is important not to lose the advantages developed through good pre-calving nutrition by under feeding after calving. Diet:

• High quality pasture should be available to appetite, if insufficient pasture is available a high quality legume hay or silage should be provided to appetite.
• High energy pellets balanced for protein and minerals.

Function:

• Having feed available to appetite stimulates a steady increase in intake
• If feed is limited cows will increase their mobilisation of body fat, this tends to drop appetite leading to a vicious cycle of increasing weight loss and falling intakes.
• Even with ad lib pasture available high yielding cows will not be able to meet their energy requirements, a high energy pellet should be fed at the rate needed to meet energy requirements at the expected peak production. This will prevent excess weight loss (cows that lose less than 0.5 of a condition score have the highest conception rates) and encourage higher peak production (production drives appetite, every extra litre at peak increases the cow's intake sufficiently to produce an extra 205L over the lactation).
  
• Low intakes early in lactation can limit the amount of minerals consumed this should be rectified by adding additional minerals through pellets. Other additives like buffers may also be required to achieve maximum efficiency of feed utilisation.