Calves

When calving on fescue pastures, timing could make all the difference to your wallet. At the Kansas State University Beef Cattle and Forage Crops Field Day in Mound Valley, Kansas, producers learned calving in the fall or spring could make or break their profitability.

According to Jaymelynn Farney, KSU southeast area extension beef specialist, there are approximately 8 million cows on tall fescue in the U.S. and most of the nation’s cattle are in spring-calving herds. She also told producers weaning prices for fall-born calves are traditionally higher.

“It’s what I call ‘poor management tolerant,’” Farney reasoned when explaining why fescue is so prevalent throughout the country. Producers have known about tall fescue’s toxicity issue since the 1940s, Farney added.

In a 19-year study on an Angus ranch in Tennessee by B. T. Campbell, W. M. Backus, C. M. Dixon, R. J. Carlisle and J. C. Waller, researchers compiled data detailing the differences between fall-calving and spring-calving herds. Researchers found fall-born heifers averaged 744 days of age to their first calving and spring-born heifers averaged 771 days to their first calving.

“Cattle make the most money when they calve around 730 to 740 days of age,” Farney said.

In the study however, spring-calving cows had a 10-day shorter calving interval when compared to fall-calving cows.

“Researchers think it’s a photoperiod effect,” Farney said. In the study, researchers also pointed out the season of breeding appeared to impact the anestrous period more than the type of cow or energy content of the ration fed. This longer anestrous period may be the cause for the cows in the fall-calving period having a longer breeding interval.

“On average, fall-calving herds had 3.6 calves per cow versus 3.2 calves per cow in the spring herd,” Farney continued. This resulted in over 200 more calves from the fall-calving herd during the study.

“More cows get bred when it’s cooler,” Farney added.

Additionally, the study found spring-calving cows calved earlier in the season. However, don’t count fall-calving cows out.

“Eleven of the 19 years, the fall-calving herd had more calves born,” Farney said. Two of the years the herds had the same amount of calves born and the spring-calving herd had more calves for six of the years.

There was no significant difference listed in birth weights between the two herds, which contrasted with other studies, Farney explained. Weaning weights were about the same but the adjusted 205-day weaning weight proved a better indicator of calf performance, she added. The spring-born calves averaged 553 pounds versus the fall-born calves’ average of 517 pounds.

Basically, the average daily gain was much higher in the spring herd, Farney explained. However, the study’s fall-calving herd had a higher gross return.

“The value of a cow in the fall-calving herd was about $1,700,” Farney said. A spring-calving cow was valued at nearly $1,400. This indicated fall-calving cows grossed over $300 per cow more than spring-calving cows, Farney added.

“Fall calves brought in more revenue,” Farney said. The fall herd brought in a total of $142,708 more than the spring herd over the course of the study, or an extra $7,511 per year. She attributed this to more calves produced by the fall-calving herd, higher prices for fall calves, and a higher number of calves sold due to a lower cull rate in the fall herd. The fall-calving cows required fewer replacements during the 19-year study.

Farney also cited a study conducted in Arkansas from 2007 to 2010 when addressing producers at the field day. She stated the study found a much higher percentage of open cows on Kentucky-31 endophyte fescue. Grazing cows on novel endophyte fescue resulted in increased fescue, she said. However, fall-calving cows still made more money, she added.

Farney said fall calving also has the advantage of fewer reproductive issues. She explained higher temperatures when breeding result in reduce pregnancy rates. For every increase in rectal temperature by 1.8 degrees F, pregnancy rates decrease by 25 percent. Toxins in endophyte-infected fescue reduce embryo development when coupled with unfavorable temperatures, she added.

“Embryo development was severely retarded when on high endophyte fescue,” she said.

She did acknowledge there are reasons producers continue to calve in the spring including weaning times could affect field work, tradition, usage of the spring flush of fescue and the fact that fall calves wean lighter.

She pointed out that to use the spring flush of fescue, cattle need to calve in January and February so calves are 2 to 3 months old when the flush occurs. Producers also need to consider spring calves may wean heavier but prices are traditionally higher for fall calves so they need to make the decision that is most profitable for their operations.

For producers who prefer to calve in the spring, there are other options, she explained.

Spring calving performance is higher on ryegrass than tall fescue when factors such as body condition scores, weaning weights, adjusted 205-day weights and pregnancy rates are considered, Farney continued. Adding clovers to fescue may help in some of those areas but it didn’t make a great difference in pregnancy rate, she added.

“Pregnancy rates are drastically increased when you graze cows on some other grass than endophyte-infected fescue,” Farney concluded. £

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