When dairy cows are grouped by production level, dairy farmers and nutritionist can formulate a ration that meets their nutritional needs. At the 29th Annual Ruminant Nutrition Symposium, Dr. Victor Cabrera, University of Wisconsin-Madison, spoke about the financial advantages of grouping cows by nutritional need.
Some of the benefits to grouping cows are; saving feed costs, improving productivity, improving herd health, and decreasing nutrient emissions to the environment. However, grouping cows by nutritional need increases the need for management by requiring additional group changes and mixing different rations.
Income over feed cost (IOFC) was the measure used to determine the effectiveness of nutritional grouping strategies. There was a clear economic advantage when nutritional grouping was employed. The gain from moving from 1 group to 2 groups was $39/cow/year, for 3 groups it was $46/cow/year, and for 4 groups it was $47/cow/year.
Grouping cows by nutritional needs also resulted in a better herd BCS (body condition score) distribution. Dairy cows that gain too much body condition in late lactation are more prone to complications in the next lactation. When all cows were fed one TMR, there were more cows with body conditions <2 and >4. When cows were fed three different TMR diets, there were more cows in the the 2.5 – 3.5 range.
Dr. Cabrera also noted that financial gains were more significant in herds over 1000 cows when up to 4 different TMRs were fed. For dairies with less than 1000 cows, the financial gains of nutritional grouping peaked at three different TMRs. Additionally, an increase in efficiency of use of N (nitrogen) was noticed. This leads to decreased nutrient emissions to the environment.