Whew, only one left. The Dickinson Research Extension Center is busy calving heifers. Thank goodness, the center only has one heifer left that is bred to a bull that will be called a noncalving-ease sire. The heifers were bred May 22. The calving season started five days early on Feb. 24, with one calf born dead. That was followed with one calf on the 25th that was assisted, two calves on the 26th with no assists, three calves on the 27th with no assists, six calves on the 28th with one assist, eight calves on March 1 with one assist, three calves on the 2nd with one assist, three calves on the 3rd with one assist, three calves on the 4th with no assists, nine calves on the 5th with four assists, two calves on the 6th that were both assisted, one calf on the 7th that was assisted, and one heifer on the 8th with no assistance.
The fact that eight heifers calved on their due date is noteworthy. Now that the calves are on the ground and we have worked through the difficulties and extra management and labor, the influence of gestation length provides measureable data. Of the 21 heifers that calved on or before the actual calving date, the average birth weight was 83.4 pounds and only three of the heifers (14 percent) required assistance. Of the 22 heifers that calved after the due date, the average birth weight was 88.7 pounds and nine of the heifers (41 percent) required assistance.
The average gestation length for those heifers that calved on or before their due date was 281.7 days and the average gestation length for those heifers that calved after their gestational due date was 286.5 days. The difference of 4.8 days in gestation length was 5.3 pounds in birth weight, which is 1.1 pounds per day of fetal growth in these heifers. This is not a good thing and only can be controlled by selecting the right bull. The bottom line, in an effort to lower calving difficulty, the average birth weight of the calf needs to be sufficiently lowered to account for a lower birth weight and for calves that may not be born on time. Keith Vandervelde, University of Wisconsin Cooperative Extension Service educator, responded and noted, “… your experience with a difficult calving-ease bull points out the need to be more aware of the top calving-ease and low birth weight expected progeny difference (EPD) bull.
The bull described was almost breed average for birth weight EPD and instead of being in the top 45 percent group, you need one in the top 10 percent of the breed. Give up some growth for a live calf because dead calves do not weigh up well in the fall.” He went on to say, “I do not know the breed you are working with, but if it is Angus, go for a calving ease value of 13 or better and minus 1 or less for a birth weight EPD. If it is a Red Angus, then insist on a minus 3.5 or less for a birth weight EPD to compare with the black Angus values. Don’t forget the heifers own genetic values contribute 50 percent and maybe you need to tone down the growth on the bulls you are using for sires of the replacement heifers.”
Vandervelde offers some very good suggestions and gives a practical solution based on numbers within the Angus or Red Angus breeds. The same process could be utilized for any of the breeds. The reason the breed or source of the bull was never stated was to encourage producers to look for solutions rather than simply put blame on a certain bull. The bull is good, but not utilized correctly. The bottom line, the numbers don’t lie. Although four-leaf clovers may bring people good luck, cows just eat them. May you find all your ear tags. — Kris Ringwall
(Kris Ringwall is a North Dakota State University Extension Beef Specialist, Director of the NDSU Dickinson Research Center and Executive Director of the North Dakota Beef Cattle Improvement Association. He can be contacted at 701/483-2045.)