Guests: Dr. Alex Bach, ICREA (Catalan Institution for Research and Advanced Studies), and Dr. Bill Weiss, The Ohio State University

In this journal club episode, Dr. Alex  Bach with the Catalan Institution for Research and Advanced Studies joins Dr. Bill Weiss from the Ohio State University. 

Dr. Weiss introduces the paper as one that's immediately applicable to the industry and answers a question he received a lot during his Extension career: What's the cost of moving cows? This research gives us some real data to help producers on cow management. (3:49)

Dr. Bach states that grouping cows is necessary, and the goal is to feed cows as close to their requirements as possible. But in a practical world, that can be difficult, and producers may resist moving cows due to the increased work and perceived drop in milk production. Dr. Bach gathered data from the field to see if that's the case or not by evaluating three farms with different diets and evaluating income over feed cost. (4:33)

Dr. Bach goes on to describe the farms and the methods his team used for estimating individual cow intakes in a group pen setting. Cow pen/group changes coincided with a diet change. Individual farms made their own ration decisions and pen movement decisions. (8:17)

In general, cows moved from a high to a medium to a low diet over the course of lactation. Primiparous cows moved from the fresh pen to the medium diet. If diet differences were adequate between groups, the loss in milk was compensated by the lower cost ration, and producers made an additional 20-30 cents per cow per day in income over feed costs. However, if the diets were more similar, lower feed costs did not compensate for the loss in milk production. (15:30)  

Dr. Weiss asks Dr. Bach if he could only build two rations, a high and a low, how would he do that? Dr. Bach’s approach is to look at a histogram of milk production in the pen and split that into quantiles. His goal is to make a ration that satisfies at least 70% of the animals in the pen for the high diet and around 60% of the animals in the pen for the low diet. (24:36)

Dr. Bach also ran a sensitivity analysis evaluating how results would change if milk prices or feed costs (or both) went up or down. He found that the higher the milk price, the more resilient a farm will be to a single diet and that feed cost is the opposite. The most interesting scenario is high feed costs and low milk prices - that's where it's almost mandatory to make groups, if you want to survive on a dairy. (27:23)

Dr. Bach evaluated the change in nutrient intake for the diet switch and projected the milk production change from that nutrient change compared to how the cows actually performed. The cows always lost less milk production than predicted. Dr. Bach thinks the main reason is that the cows were overfed before moving. (37:46)

Dr. Bach invites the audience to experiment a little bit with grouping cows. Don't be afraid of losing milk, and look beyond milk. Put in place mechanisms on the farm that allow you to measure income over feed costs as the ultimate goal. Cows are flexible, so don't be afraid of making a mistake. If something goes wrong, it will go wrong for a short period of time. You can correct it. You can change the diet right away, and the cows will recover. (46:14)

You can find this episode’s journal club paper here: https://doi.org/10.3168/jds.2022-22875

Author: Dr. Alex Bach

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