Winter weaning takes place this year at the Dickinson Research Extension Center. This concept is an outcome from the question, "When should I calve?"
For the past four years, the center has calved on grass. Initially, the May- and June-born calves at the center were weaned at the traditional early November dates, held in confinement pens for up to a month and then put back out on winter paddocks and supplemented.
After three years of weaning younger calves, the questions started to come up: Why not wait to wean in January? Mid-May versus mid-March calving cuts 60 days of growth and 60 days of value, if sold at traditional weaning times.
Last year's early fall frigid temperatures, in contrast to this year's mild temperatures, created challenges and the memory lingers. Weaning is always a stressful time. Weaning lighter, younger calves in inclement weather is tough. Management inputs are different than for older calves, and many producers are not set up to wean younger calves. Are the feed bunks the right height? Can the younger calves reach the water?
These are simple, but important, questions. Remember, most calves can handle the weaning, but some calves were born mid-June and are only 5 months old. In reviewing the problem calves, the lighter, younger heifer calves particularly struggle.
As the center staff pondered the consequences of May calving, the consensus was positive: Labor inputs are decreased and calving is much more manageable. But there is no way around the fact that November weaning of May-born calves takes 60 days of growth off the traditional sale ticket, plus negative impacts of weaning younger calves in regard to potential health problems are very real.
In reviewing the center's calving and weaning efforts in 2009, 2010 and 2011, the average calving date was March 29. In terms of starting the season, the third mature cow calving date is a good indicator of the official start of the calving season.
The average date the third mature cow calved was March 15 for those years. The calves from these years averaged 205 days of age at weaning and gained 2.5 pounds per day during the summer while nursing their mothers. The three-year average actual weaning weight was 598 pounds.
Following the 2011 calving season, the center delayed bull turnout until Aug. 1 for May calving. In 2012, 2013 and 2014, the average calving date was May 25. Again, using the third mature cow to indicate the start of calving, the average date the third mature cow calved was May 7. The calves from these years averaged 168 days of age at weaning and also gained 2.5 pounds per day during the summer while nursing their mothers. The three-year average weaning weight was 514.
Interestingly, there is no difference in calf gain between the March/April or May/June calves. If both groups of calves were weaned at 200 days of age, the March/April calves would be estimated to weigh 586 pounds (average daily gain plus birth weight) and the May/June calves would be estimated to weigh 589 pounds (average daily gain plus birth weight).
If the center sold in November, 60 days of growth at 2.5 pounds equals 150 pounds of missed growth. So, mid-January is now the targeted weaning time. The calves will be brought home; their mothers will be left on winter paddocks.
Remember, traditional bulls are turned out June 1, calves are due March 12, weaning will be in early to mid-November, and cows start their last trimester of pregnancy Dec. 12. In a later calving system, bulls are turned out Aug. 1, calves are due May 12, weaning is in early to mid-January, and cows start the last trimester of pregnancy Feb. 12.
The May calving system simply shifts the important dates in the management of a cattle operation by 60 days, but it does not change the growth of calves or the need to change cow nutrition according to their stage of production.
For the center, as for producers, changes in the management are not simple. Producers need to think well in advance and project the consequences of a change. Changing from March to May calving must account for and provide husbandry to move weaning into January, or at most, provide an adequate backgrounding program for younger weaned calves. In addition, producers must change the date for increasing cow nutrition during the last trimester of pregnancy from mid-December to mid-February.
The nutritional shift for cows is a good change, putting winter feed on the down side, with spring soon to arrive. The later management of calves is not as simple, thus a change in calving date is a big change for any operation.
May you find all your ear tags.