I once heard a story of a woman who always cut her roasts in half and cooked them in 2 pans. She never questioned the practice. It was what her mother taught her so she always did it that way. Finally, she asked her mother why she cut her roasts in half. Her mother explained that she did not have a roasting pan large enough for a whole roast. I don’t know if the story is true but it’s a good analogy. Sometimes our cow grouping strategies are like that. Maybe cows are still grouped the way they were when they were milked in the parlor. Maybe they are grouped to avoid teaching them to use a robot that they enter from the opposite direction. We all recognize that first calf heifers have different needs because they are producing less and growing more. Recent research makes it clear that they spend their time differently too.* This research may change your mind, or it may reinforce your convictions, depending on how you group your cows today.
Grouping cows by parity is popular whether they are milked in robots or parlors. PMR or TMR for a specific lactation group can be formulated for specific metabolic needs. Stalls might be sized differently for different lactation groups. Social interactions at the bunk, waterer, and free stall level can be less stressful if cows are grouped by lactation. On the other hand, most herds are about 30% first lactation so it requires at least 3 pens, or different sizes of pens to accommodate a first lactation pen. Many robot barns are constructed with all left-hand robots in some pens and all right-hand robots in other pens. Switching from left-handed robots to right-handed robots may require some retraining.
In robot barns there are more reasons to group cows by parity. Heifers milk more frequently if the robots have more idle time. Boss cows can block timid heifers from going through the entrance gate, exit gate, or robot. Training and fetching heifers can take away robot time, and disrupt cow flow, for the whole pen. Training heifers doesn’t have to disrupt the mature cows if heifers are in a separate pen. If kicking heifers cause downtime on the robots, that downtime can be limited to one pen by separating cows from heifers.
Researchers at Clemson University found that first lactation cows spend more time in the commitment pen than mature cows. Mature cows came to the commitment pen more often than heifers so they were sorted to the bunk more often than the heifers. Not surprisingly, mature cows spent more time in the robot than first lactation cows, since mature cows make more milk. First lactation cows were slower to leave the robot after milking was complete. We all know how heifers can kick at the robot arm. Mature cows also showed signs of stress in the robot, but their tail swishing and stepping is less destructive than a kicking heifer. Out in the barn, mature cows had more lying time – especially during the night. First lactation cows were up and down more times than mature cows.
This cow behavior information can be used to customize stocking density, and system settings, to allow more time for first lactation cows, and move mature cows through the system more quickly. Commitment pen population can be adjusted in the first lactation pen, to allow for the fact that those cows will stay there longer. Milking permission can be more restrictive for mature cows, knowing that they come back to the sort gate more often and there will be more opportunities to milk them. It may be practical to have more cows per stall in the heifer pen because they are in and out of the stalls more frequently.
Cow Corner can help fine tune settings for your barn. If you are able to separate first lactation cows from mature cows, we can optimize each pen for the cows that live there. If you are not able to separate lactation groups, we can adjust gate settings, milking permission, and feed tables to allow both groups the best opportunity to thrive together.
*Impact of parity on cow stress, behavior, and production at a farm with guided traffic automatic milking system Lindsey Davis1†, Elizabeth A. French2, Matias J. Aguerre1 and Ahmed Ali1,3† 1Animal and Veterinary Sciences Department, Clemson University, Clemson, SC, United States, 2U.S. Department of Agriculture, Agricultural Research Service, U.S. Dairy Forage Research Center, Madison, WI, United States, 3Animal Behavior and Management, College of Veterinary Medicine, Cairo University, Giza, Egypt
Comentários