TRACK YOUR HEIFER TRAINING

My college coursework at UW Platteville included a lot of production agriculture classes, so there was less time for calculus and statistics. I didn’t know what a standard deviation was until 40 years later when I wanted to understand algorithms for activity monitoring systems. I discovered that a standard deviation tells how much the data varies from the average. Doc Hoffman did cover that in my basic dairy production class. “The average doesn’t mean much if you have one foot in a bucket of ice water and the other in a bucket of boiling water.” That’s why it's important to track your heifer training. Average daily milkings for fresh heifers can be deceiving. Even if they average 3 milkings, half of them are milking less than 3 times a day – maybe a lot less.

Recently I got to evaluate a data set for a uniform group of heifers. They were all sourced from the same farm, raised under the same conditions, calved in the same season, and had similar genetic potential. As a group, they averaged 2.7 milkings at 21 days in milk. That number is slightly skewed because these heifers were milked in a parlor at freshening, and introduced to the robot barn 10 to 30 days after calving. To look beyond the average, I tracked individual weekly milk weights and milkings through 90 days in milk.

Each dot represents a heifer. At 22-28 days, the distribution is more interesting than the trend. 29 of the 36 heifers were

between 2X and 3X. Some of the heifers had just been moved to the robot barn, while others had been there for more than 2 weeks. Some were still being fetched under the training protocol and others were coming to the robot on their own. Ideally, there would be less variation, and fewer heifers with less than 3 milkings. Keep in mind that some heifers may have had only 1 or 2 opportunities to be milked on their first day, depending on when they arrived in the robot barn.

By 36-42 days, the trend is clearer. The highest producing heifer has the highest milking frequency and the lowest producing heifer has the lowest milking frequency. There are individuals with 80 pounds of milk on less than 2 milkings, but no heifers are over 100 pounds with less than 2 milkings. All of the heifers with less than 60 pounds of milk were milked less than 2.5X. All of the heifers with 3 or more milkings are making 80 pounds of more.

The 64–70-day graph shows fewer heifers milking less than 2X comapred to the previous graph. Given time, they began to get the barn figured out and find their way to the robot on their own. At this stage, some of the heifers that started out milking 2X are now milking more than 2.5X, but they are producing less because they got a slower start.

The final chart tracks the subsets of heifers that had the highest and lowest milking frequency. Each line is a single heifer. There was not a lot of variation in the first week. 8 of the 11 were milked between 2.4 and 2.8 times at 22-28 days. Most of the heifers sorted

themselves to the high or low group by 29-35 days. There was complete separation between the groups by 36-42 days. After they sorted themselves into groups, the ranking within the groups changed, but no heifer moved from the high group to the low group, or the low group to the high group. Heifers that reached 3X by 36 days in milk maintained 3X through 90 days. Those that were 2X at 36 days in milk never averaged more than 2.5 milkings. Effective early training consistently set the heifers up for success. Ineffective training consistently limited milkings through the first 90 days.

Don’t just look at the average. Focus on the below average cows. Want to see how your heifers compare? Cow Corner can help you analyze heifer performance, and identify the bottlenecks that are holding them back.