Animal Health & Nutrition
Rick Lundquist is an independent nutrition and management consultant based in Duluth, Minn. He provides livestock production advice.
Summer Heat Stress Culminates in Fall Lameness
Sep 13, 2010
The incidence of lameness typically peaks at the end of summer. Data presented at the 2004 International Symposium on Lameness shows that the number of cows treated for lameness in September is more than twice as high as in the other months. It’s not surprising, considering the effects of summer heat on hoof health. Unfortunately, unless you live in the Southern Hemisphere, it’s too late to do anything about it now.
But, if you’re dealing with a lot of lame cows now, it’s a good time to start being proactive about next year.
Summer heat stress culminates in fall lameness.
1. Panting to dissipate heat causes respiratory alkalosis, increasing urinary bicarbonate loss, which lowers rumen pH.
2. Loss of saliva from drooling also reduces rumen buffering capacity.
3. Heat stress reduces cud chewing and fiber digestion, lowering rumen pH.
4. These changes cause metabolic acidosis, resulting in vaso-constriction and dilation, leading to the breakdown of connective tissue in the hoof.
5. At the same time, excess standing, especially on concrete, in a wet, humid environment caused by sprinklers, mud and manure soften the hoof, resulting in hoof wear and lameness.
Management to reduce lameness.
1. Keep cows comfortable with good heat abatement (fans and sprinklers).
2. Minimize standing by providing clean and comfortable freestalls or bedding areas.
3. Minimize walking and standing on concrete. Install rubber mats over concrete in walking lanes and behind the feed alley.
4. Minimize time spent in wet and muddy areas and keep alleyways clean.
5. Identify lame cows in the early stages and have a regular hoof trimming program.
6. Use a foot bath (only if it is cleaned and changed frequently).
Nutrition to reduce lameness.
1. Feed a well balanced diet with adequate forage and fiber length.
2. Feed a proven organic zinc product to increase hoof hardness.
3. In my opinion, the most important nutritional consideration is to provide a well blended TMR that prevents feed sorting. Feed sorting contributes to more nutritional lameness than any other factor in TMR-fed herds. Keep the moisture content of the TMR high enough to effectively blend all ingredients. Don’t feed straw or long hay in the TMR and expect it to help if it doesn’t stay blended in the TMR. Increased feeding frequency will also help to reduce sorting.