al., 2011).
- Field survey data collected by the Keenan Co. in Europe (courtesy of D. E. Beever, Richard Keenan and Co., Borris, Ireland) indicate strongly positive effects on health. In 277 herds (over 27,000 cows) in the United Kingdom, Ireland, France and Sweden, changing to the high-straw low-energy TMR system decreased assisted calvings by 53 percent. In addition, the change decreased milk fevers by 76 percent, retained placentas by 57 percent, displaced abomasum 85 percent, and ketosis by 75 percent. Using standard values for cost of these problems, the average increase in margin per cow in these herds was $114 just from improved health alone. While these are certainly not controlled research data, they are consistent with the results in our research as well as field observations in the U.S.
- The same sources of observational data indicate that body condition, reproductive success, and foot health may be improved in herds struggling with these areas. A recent meta-analysis underway of our studies in this area shows that controlling energy intake decreases time to conception by 10 d compared with overconsumption of energy (Cardoso et al., 2011, unpublished data).
- Although data are limited, milk production appears to be similar to results obtained with higher-energy close-up programs (Richards et al., 2009; Vasquez et al., 2011). There is some evidence that persistency may be improved, with cows reaching slightly lower and later peak milk. Therefore, producers should be careful to not evaluate the system based on early peaks and should look at total lactation milk yield, daily milk, and, over time, indices of reproduction and other non-milk indicators of economic value.
- Straw and corn silage generally are lower in potassium and calcium, and thus help control the dietary cation-anion difference (DCAD) without excessive addition of anionic salt mixtures. Blood calcium concentrations decrease less when energy intake is controlled before calving (Dann et al., Janovick et al., unpublished data).
- The program may simplify dry cow management and ration composition in many cases.
- Depending on straw cost, rations based on corn silage and straw likely will be no more expensive than the average cost of traditional far-off and close-up diets, and could be cheaper where straw is plentiful. Remember that even when straw appears expensive, it is replacing something else in the diet so marginal cost is the key criterion. Furthermore, total DMI per cow may be lowered by addition of straw, so that feed cost per cow per day can actually be decreased substantially.