By Sandy Johnson, extension beef specialist, Colby, KS
A year ago at this time, wet weather had delayed planting of many spring crops. This year, cool soil temperatures are doing the same. Grass growth has also been delayed, and in many cases winter feed supplies are running short. The challenge for many operators is to give the grass as much time as possible given the current weather conditions, balanced with how long winter-feed supplies can be stretched.
This balancing act may be hard to do and have cows in the position to conceive early in the breeding season as normally expected. For many, high quality spring grass plays a key role in getting cows cycling at the start of the breeding season. While good managers only grazed half of the available forage during the last grazing season, using last year’s grass to start this breeding season will leave cows short on energy. If quality or quantity of forage is limiting, resumption of normal estrous cycles could be delayed. In addition, if forage resources initially meet demands but then decline, embryo survival could be reduced. Depending on the timing of your breeding season in relationship to spring grass, delaying the start of breeding for a week or 10 days may be prudent. Another option would be to provide some type of energy supplement on pasture, which brings its own set of challenges.
Starting the breeding season when cows are thin or not in a positive energy balance, only means that the bulls are turned out and not necessarily that cows will conceive and retain the pregnancy. Little is gained if only a few conceive early and others slowly trickle along. The gap between the early few and the bulk of the calves creates challenges for many aspects of management and certainly to marketing the calves.
If cows are thinner than normal or declining in condition and grass is behind in growth, delaying the start of the breeding season should result in the subsequent calf crop being more uniform in age and weight, presuming the grass catches up. Depending on conditions the next year, moving the season back a few days each year should have this timing back to “normal” in a few years. While you could wait until next year to take action and try to induce the later calving cows to cycle earlier to get back on schedule, you would still have the strung out calf crop to market. An extended calving period may also negatively affect the number of early born replacement heifers available from this calf crop.
It is nice to stay on the same schedule each year, but Mother Nature doesn’t always make that easy. Cows should be in a positive energy balance and have ample forage supplies to carry them through before the breeding season is started. If delayed spring grass growth makes that questionable, consider a delay in bull turnout so more cows are cycling when the breeding season is started.
