Cows under heat stress are more susceptible to subclinical rumen acidosis. Although the use of buffers, such as sodium bicarbonate, sodium sesquicarbonate, and magnesium oxide help neutralize rumen pH, they do not act upon the cause, which is a reduction in rumination and cud chewing.
To maintain a healthy rumen, cows require adequate amounts of effective fiber in the diet. During periods of warm weather it is advisable to use energy dense forages having highly digestible fiber concentrations. In addition to diet reformulation, other measures need to be implemented that help reduce the effects of high ambient temperatures on the animals, such as forced air, sprinkler systems, etc.
Figure 1: Laminitis treatment in 10 herds by month and cause.
Source: Adapted from Cook et al. (2004).
Table 1. Effects of effective fiber on milk yield and components.
|Milk yield (Lbs./d)||54.1||56.8||58.1||50.0|
|FCM 3.5% (Lbs./d)||51.0||55.2||56.1||50.6|
|Efficiency (FCM /intake)||1.35||1.53||1.56||1.47|
|Fat yield (Lbs./d)||1.69||1.87||1.91||1.78|
|Protein yield (Lbs./d)||1.83||1.83||1.78||1.50|
FCM = Fat corrected milk (3.5%); Source: West et al. (1999)
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