Are you overfeeding your lactating cows? Victor Cabrera says if you are feeding all your cows the same ration, that is likely the case. Cabrera is an assistant professor at the University of Wisconsin Dairy Science Department and a dairy management extension specialist for UW-Extension. He presented a session on grouping strategies at the Four-State Dairy Nutrition and Management Conference held June 13 in Dubuque, Iowa.
Farmers and nutrition consultants often target rations for the high-producing cows in the herd, which often overfeeds low-production to medium-production cows.
Grouping cows properly will decrease feed costs and increase income over feed costs. Test records from a number of Wisconsin dairies were collected and analyzed using the online tool “Grouping strategies for feeding lactating dairy cattle” Click here to view.
The comparison showed that when changing from no grouping to three same-size feeding groups, farms could realize between $161 and $580 (mean $396) of additional income over feed loss before additional costs and losses were factored in.
Cabrera says proper rations will not only save money on feed but also reduce nutrient excretion and decrease environmental concerns.
“Additional groups increase feed efficiency,” says Cabrera. “Think simple. If you have two cows on the same diet, chances are one is getting more or less than she needs. Since you can’t individualize the diets, the best option is to group them.”
Additional costs producers are likely to see when grouping cattle by feed needs include additional labor to prepare more feed rations and possible milk depression that could occur for a period of time after moving from one group to another due to social interaction adjustments or because of receiving a lower nutritive diet due to the re-grouping.
Cabrera says that even when factoring possible costs, the net return of grouping cows is still much more profitable than not grouping.
He discussed a number of factors when deciding how to group cows, including but says the four most important are days in milk after calving, fat-corrected milk, dairy merit (fat-corrected milk and bodyweight) and clustering cows based on crude protein and net energy.
The maximum number of cow groups fed different rations is going to depend upon facilities and management, but Cabrera says there is little gain from feeding more than four different diets.
The methodology Cabrera recommends has been implemented into an online tool in the Wisconsin Dairy Management webpage: Tools: Grouping strategies for Feeding Lactating Dairy Cattle. This online tool is free and available to anyone.
Before using the online tool producers should gather the following data: cow identification, parity, DIM, milk production and milk fat content. For greater precision, cows’ bodyweight could also be used. If bodyweights are not available, an average weight for first-lactation and multiparous cows can be used.
Cabrera says that farms that are already grouping their lactating dairy cows may benefit from reviewing if they have the best number of groups, are grouping the cows to the best criterion and adjusting the diets of each of the groups.
The online tool at DairyMGT offers an algorithm with a set of questions to assess the current farm situation, which is then used to analyze for the best possible grouping strategies for feeding lactating dairy cattle. PD
Boylen is a freelancer based in northeast Iowa.
