PSU Herd IOFC –September 2011
by Virginia Ishler
The challenge for September has been the fat test. The end of August and the first test in September gave the appearance that the herd was moving back up to 3.50%. Then it dropped to 3.30% and has not budged for the entire month. We have been feeding the BMR corn silage at 50% of the ration dry matter. I decided to go back to our winter type ration of 40% corn silage and 17% haylage. This lowered the canola meal and increased the corn by a few pounds. The ration still contained 65% forage. This change was made during the second week of September. Evaluating production for the month, it was striking that for the first two weeks production averaged a consistent 73 pounds and weeks three and four the cows averaged 79 and 81 pounds respectively. So we got a production response but fat test stayed the same.
After our September DHIA test I evaluated the groups’ fat tests comparing against August. This is where I found my answer. Comparing fat test in August and September, the high group and 2-year old groups went from 3.30% to 3.53% and 3.40% to 3.54% respectively. Since we test at the end of the month, this improvement in fat test corresponds to the ration change. The fresh and low groups remained the same at 3.55% and 3.70%, respectively. These two groups are receiving diets formulated for their specific requirements and their rations have not changed. The problem group was the tie-stall barn, which was at 3.0% fat. These are animals on research trials receiving all different kinds of diets. When I took the milk component contribution of each group and calculated the fat test for the herd I came up with 3.39%, which was very close to what we got in the bulk tank. To get the herd test to at least 3.50%, the high and 2-year old groups would need to average 3.7% fat and with the groups averaging 106 and 82 pounds that may not be achievable. However, this demonstrates how one group contributing 22% to the bulk tank can have a huge impact on the overall herd. It also means that making ration changes for the herd are futile right now because as long as tie-stall cows are testing that low there may be very little opportunity for improvement.
The extremely wet weather has made it hard to get corn silage harvested. Yields per acre are down so it requires covering more ground to get our bunks and bags filled. We are opening the last bunk of 2010 corn silage, which should last until January. It appears that our tonnage request for corn silage may not be met. Fortunately we have ample straight alfalfa and grass silage stored. With the potential of limited corn silage, the young-stock will continue on all hay-crop forage and so far the dry cows and springing heifers have done well on limited corn silage (5 pounds of dry matter).
For the month of September the herd averaged 76 pounds with a 3.34% fat, 3.00% protein, 222,000 SCC and 7.4 mg/dl MUN.