Farming Magazine - December, 2013


Beef: Green-Grass Calving

By Dr. John Comerford

Photo by nessmoon/

Bull consignors recently delivered bulls to the Pennsylvania Bull Test, and it occurred to me the bulls were more often born in March and April than they had been in the past. I took a cursory look at birth dates in tests a number of years ago, and it certainly appears the bulls were born earlier in the year. The conventional wisdom has been that calves born earlier in the year (January through March) will make more money because they will be bigger at weaning and return more dollars at the feeder calf sale. Is this still sound thinking?

Heavier calves

If we examine a summary of feeder calf prices in West Virginia compiled by James Pritchard (2009), the report indicates that M1-grade feeders at 535 pounds averaged $94.33, and those averaging 603 pounds averaged $86.32, making the heavier calves worth about $20 more for the extra 65 pounds in weight.

This difference in sale weight could easily occur in many herds with a difference in birth date from late February to late May. The prevailing question is what the additional cost may be for calving cows in late February compared to late May, and whether this cost is more than the $20 realized by the older calf.

Feed cost

For cows calving in late February in the mid-Atlantic region, we can expect to feed about $50 worth of hay until green-up and pasture availability. Since the nutritional needs of the cows are peaking in midwinter, hay will often not be enough for late-gestation cows with average or better milk production expected.

Conservatively adding a pound of protein to the diet for 60 days will add an additional feed cost of $12 to $15 per cow. Most research shows beef cows have a peak in milk production 60 to 90 days after calving, so a calf born in February may have the most milk available before pastures are ready. This results in giving purchased feed to cows to reach peak milk production. As the cost of feed inputs increases, it is important to compare the weaning weight and value advantages to the greater purchased feed cost.

Photo by Bev Lloyd-Roberts/

Calf health

Consider the view of a calving area in March in the mid-Atlantic region compared to one in May - snow and mud versus green grass. Obviously, cows will usually be more confined, they will be concentrated around a hay feeder, and there is little opportunity to separate cows after they calve in March or earlier. This scenario leads to udders being dirty and resulting scours in the calves, injury to calves, and mud and aggravation for farmers.

Compare that scenario to the Sandhills calving system developed by researchers at the University of Nebraska-Lincoln. This system was created to help prevent scours and other disease issues in young calves.

In this protocol, cows that have not calved in the herd are moved to a new location every two weeks, while cows with calves stay together. This prevents older calves from transmitting bugs to newborn calves, and also prevents the buildup of pathogens at a single location. In our region, this system can only be used if there are functional paddocks available to keep moving these cows. Absent the availability of a number of hay feeders, winter water in multiple locations, and access to facilities if needed, this implies healthier calves may be possible when pasture is available.

Replacement heifers

There is a legitimate question of whether heifers born in May will be reproductively mature enough to be bred the following May. Experience with heifers for the past three years in the Pennsylvania Heifer Development Program has shown us that heifers born in April and bred around May 1 to a synchronized estrus did not differ significantly in pregnancy rate from those born in earlier months.

The key to breeding heifers at 12 months of age will be in proper development so they reach a critical weight and are healthy, with a nutritional environment that allows them to cycle, maintain adequate growth and be fertile.

Weaning and marketing

Research studies comparing weaning calves at 4 to 5 months of age to the normal 6 to 7 months have shown there are several advantages to weaning the calves early. The results in Table 1 (see page 54), for example, show cows gain more weight and are in better condition after a calf is weaned early. Other studies indicate that cow costs are lower since lactation is shorter, cows may rebreed faster, and calves will perform better postweaning.

Unlike other areas of the country, marketing sources are plentiful for the smaller and younger calves in the region. Since herd sizes are smaller, feeder calf buyers usually need to package groups of calves from an array of weights and ages. Cooperative feeder calf sales can often designate a delivery date that will allow the smaller and younger calves to be sold several weeks or months prior to delivery.

Table 1. Effects of early weaning on cow weight gain and condition score

The downside

As with any management program, there are going to be some compromises to make with green-grass calving. First, haying and crop farming will be in high gear in most areas at the same time calves are hitting the ground. The division and availability of labor to effectively manage cows at calving while making hay and planting crops can be a problem for small breeders. Secondly, the peak breeding season for the herd then becomes July and August, often the hottest and driest part of the summer in the region. Forage availability, grazing time and breeding activity may be reduced.

Dr. John Comerford is an associate professor and extension beef specialist at Pennsylvania State University.