Adapt Rations for Summer Feeding.
Dairy Pipeline: July 1995
Charles C. Stallings
Extension Dairy Scientist, Nutrition
Feeding during hot, summer conditions is a special challenge. Dry matter intake, milk production, fat and protein test, and reproductive efficiency are all reduced when temperatures get above 80$#176 F for extended periods. There are some feeding and nutritional modifications that can be made to assist in keeping cows eating and milking well. 1. Feed an extra meal or two. An extra feeding during hot weather will help prevent secondary fermentation and heating of feed in the bunk. Also feed during the cooler parts of the day when cows are more likely to consume feed. 2. Feed a ration with a higher concentration of energy. This is sometimes hard to do because the amount of concentrate and fat is at a maximum already. Feeding more concentrate increases energy consumption as long as we supply a minimum of 18 to 20% ADF. High fat feeds such as whole cottonseeds, tallow, and commercially available ruminal protected fat sources can increase the energy density of the ration, but overall fat of the diet should not exceed 7% of the dry matter. 3. Avoid excessive levels of ruminally degradable protein. Generally it is not advisable to feed a ration with more than 18% protein in hot weather. Also rations with more than 65% of the total protein as ruminally degradable should be avoided. Excess nitrogen must be excreted at the expense of energy. 4. Feed extra potassium, sodium, and magnesium. Potassium should be 1.5-1.6% of dry matter, sodium .45-.60%, and magnesium .35-.40%. 5. Some feed additives may be needed. Sodium bicarbonate may be needed to supply sodium and buffer the rumen due to higherconcentrate feeding. Usually .3-.5 lbs./cow/day is recommended. Yeast has been used to assist with keeping cows eating and increase fiber digestion. These suggestions will not prevent summer slump but they may help you manage a difficult situation.