Robot herds are unique in that there are management changes built into the system for different stages of lactation. In most parlor herds, once cows leave the fresh pen, they stay in the same pen, get milked the same number of times, and eat the same ration throughout the lactation. Robotic milking systems can be set to adjust the milking frequency and pellet feeding according to milk production and stage of lactation. It makes sense to group data by lactation number and stage of lactation to evaluate the effects of those changes. Does milk production drop when cows move from a days-in-milk feed table to a production table? How about when the milking permission shifts from early lactation to mid-lactation?
The Cow Corner weekly report includes graphs of milk production, pellet consumption, and milkings by lactation group for 0-50 days in milk, 50-100 days, and 100-200 days. These groupings give insights into the effect of milking permission and feed table changes through the course of a lactation. Granted, cows move from one stage of lactation to the next each week, so each group includes different cows each week. Still, we can discover patterns and draw conclusions by comparing cohorts to themselves, and to benchmarks over time.
This graph uses Lely data to show trends for milkings, milk yield, pellet consumption, and refusals for first lactation cows under 50 days in milk. The good news is that milk yield has increased over time. It is also evident that pellet consumption has increased with milk production. On the other hand, the increase in milk production has come with a decrease in visits and a larger decrease in refusals. The graph should not be used to infer cause and effect. It could be that the feed table was changed, and a higher level of pellet feeding resulted in more milk production. Or, we could speculate that heifers are transitioning to lactation better, and the feed table allocated more pellets because they were producing more milk. We need more information to be sure which is the case. The decrease in milking frequency and refusals shows that the barn is not moving as well as it was, and slower traffic may be leading to lower production in the near future.
A similar graph, from a DeLaval database, shows a group of mature cows between 100 and 200 days in milk. It is important to remember that many of the cows that were 100-200 days in milk at the end of January (left side of the graph) were over 200 days in milk at the end of March (right side of the graph). The graph does not track the performance of specific cows in the herd. It does track performance of management groups. Milk production for this management group increased more than 8 pounds between January and March. Visits remained constant during this time while robot pellet consumption went down. We should not conclude that decreasing pellets caused increased milk production. We can conclude that decreasing pellets did not decrease milk production or milking frequency. Note that pellet consumption (what the cows ate) is less than half of pellet ration (what the cows were allowed). In this example, consumption is unusually low as compared to ration. The maximum feed per visit was intentionally set to be more limiting than the feed table.
Either graph can be used to compare to herd goals or industry benchmarks. In the first graph, for example, 7-day average production ranges from 60-73 pounds per day. The DRMS average benchmark for this group is 69 pounds and the range for the first standard deviation is 60 to 78. The group has definitely made progress in comparison to that benchmark.
I can help benchmark your herd performance today or track trends over time. I can customize a program to fit your needs. Visit the Cow Corner website for more information.
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