- Jin Gan
Adjusting Summer Diet For Dairy Cows
During summer, cows will face heat stress which affects feed intake. This will cause reduction in milk production, which results in financial loss to producers.
Energy And Protein Adjustments
Diet adjustments can help the cows go through this period of heat stress.
Different feedstuffs will contribute different amounts of heat depending on the heat of fermentation or the efficiency of use by the end products.
In general, corn and other concentrates contribute less heat as compared to forages.
The increased in corn will result in decreasing fiber.
If there is insufficient fiber in the diet, rumen mat becomes diminished and there is less rumination, causing less chewing activity.
Forages can be lowered but rations still need to provide ADF levels of around 19 - 20% and NDF levels of 28 - 30% to be sufficient.
Feeding high quality, digestible forage will enable the dietary ADF to be lowered but still enough energy for the animal.
In order to maintain energy in the diet, incorporate fat into the diet as fat contains 2.25 times more energy than carbohydrates.
Commercial rumen bypass fats are recommended as a fat source.
Fat level should not exceed 5% of diet dry matter.
It is also important to supply sufficient protein and good balance of carbohydrates and soluble protein for microbial growth.
Increased fluid losses due to sweat or urination will alter the balance of cabonic acid and bicarbonate.
These losses will affect the cow's cation-anion balance.
Depending on the diet, it is encouraged to feed about half a pound buffer as sodium bicarbonate or sodium sesquicarbonate.
Sodium should be around 0.4% - 0.5% of the diet DM.
Potassium carbonate can also be fed to provide buffering and to raise dietary potassium to about 1.6 - 1.8%.
Other Dietary Factors
Liquid feeds can be added to the diet to alleviate any sorting out of the forages the cow may be inclined to do.
Bunk stabilisers can also be added to lessen the effects of feeds that have questionable bunk stability.
It is crucial to ensure there is ample clean water available for the cows at all times.
Adjusting feeding times result in more stable feeds.
Feeding early or later in the day will allow animal to consume more feed as it is cooler.
Animal produces most heat of fermentation 3 - 4 hours post feeding. Feeding during cooler part of the date allows the animal to dissipate more heat before enduring the extreme heat in the date.
This will also result in less spoiled feed as less feed will sit in the feedbunk during midday.