|
Twin Beef Calves – A Blessing Or Curse?
DR. TERESA L. STECKLER
SIMPSON, ILL.
For the last 6 weeks I have been traveling throughout southern Illinois collecting samples for a grant. I have been to many farms and met many new cattlemen. I am always awestruck at the ingenuity of cattlemen! During my conversations several cattlemen have relayed to me that they have several sets of twins on the ground. It seems that there are more twins than ever – but that may simply be due to not hearing about all the cases before!
Twinning in beef cattle is fairly rare but more common in dairy breeds. Holsteins, for example, typically deliver twins about once in every 29 live births. Brown Swiss are even more prolific, birthing twin calves once in about every 11 deliveries. However, twin births in beef cattle occur in 1 to 7 percent of cattle depending on breed and genetics. For example, Angus cows only deliver twins once in every 91 live births.
Research has clearly shown that twinning rate in a beef herd can be increased. The best-known research on twinning was conducted by the US Meat Animal Research Center at Clay Center, Neb., from 1981 to 2012. By 2001 the researchers had moved the twinning percentage from approximately 4 percent in various breeds up to 50 percent. This was all done by selection for cattle that twinned. The rate was still at 50 percent in 2012.
Researchers at the Clay Center found that as long as there is good nutrition, there is only a 10 percent difference between the weights of twin calves and single calves when weaned. The twins can, in most cases, almost double the income from a single cow. Certain breeds, such as Simmental, Charolais, and Holstein, and also large heifers are more likely to produce twins.
Although twinning reduced calf survival, dams producing twins at birth weaned 70.8 percent more calves than dams with a single birth. This resulted in a 48.1 percent increase in total weaning weight (740 pounds vs. 499.6 pounds).
On the downside, cows that deliver twins have twice as many problems as cows that only deliver a single calf. When cows had dystocia, calf survival at birth was 95 percent for singles and 73 percent for twins compared with 99 percent vs. 92 percent when no dystocia was experienced. The research herd had about a 50-60 percent rate of twins within the herd of 250 cows but it only had an 80 percent herd calving rate. Survival at birth was greater for single-born than for twin-born calves, but twins and singles did not differ in postnatal survival. With the high twin rate, the herd still manages a 120 percent calf crop. Cows that deliver twins also have a much larger feed requirement.
Additional differences between twin birthing cows when compared with single-birth counterparts: shorter gestation lengths, more retained placentas, more dystocia, more days to estrus, lower conception rates, and more days to pregnancy. Days to estrus, conception rate and days to pregnancy were not affected by number of calves reared in cows birthing twins.
Further, calves born as twins were lighter at birth, 100 days and 200 days, but twins and singles did not differ in post-weaning gains. Total calf weights at 100 days per cow calving were 12 percent greater in cows birthing twins vs. singles, when twin calves reared by foster dams were excluded. Put another way, this suggests the smaller calves just needed longer to reach equivalent weights with their single-born counterparts.
Thus cattlemen may be right when they say “twins are just too much trouble.” It's common for the mother of twin calves to reject one of her calves and refuse to nurse it. That leaves the cattleman with the option of finding another cow willing to accept the calf (grafting) – not always an easy thing to do – or bottle feeding the calf two to four times a day. In addition, cows that give birth to twins are pulled down and will rebreed later than the other cows in the herd.
Gestation length of twins is from 1 to 2 weeks shorter than for single calves, so if a cow became pregnant with twins early in the breeding season she will likely be one of the first to calve. Sometimes this happens unexpectedly ahead of your target calving dates.
Multiple births are also physically demanding on both the mother and her calves. The additional strain of multiple deliveries can tear up the cow's uterus, and crowding during fetal development sometimes results in deformed or weakened newborns. Even if the births come off without complications, it’s not uncommon for a single cow to be unable to produce enough milk to adequately feed both her calves. Cows nursing twin calves require about 13 percent more energy intake to maintain body condition.
In case you should encounter twins within your own herd, here are some tips for how to deal with them. Feed the cow well in her last trimester of pregnancy, if known, and while she is nursing the twins. Be there to help the cow deliver and, if possible, keep the cow and twins in a small pen for at least 24 hours to encourage bonding. Make sure both calves receive an adequate amount of colostrum. Many times one calf will get up and nurse while the other will hang back. It is important producers keep a close eye on them and make sure they both receive their proper amount of colostrum, even if it requires bottle-feeding them.
If possible, start the calves on feed as soon as possible to make up for lower levels of milk and prepare them for the possibility of early weaning. Since calves can be weaned as early as 60 days, early weaning could be a possible method to let the cow recover and rebreed sooner rather than later. Do not save a twin heifer as a replacement if she is born with a bull brother since 95 percent of the time she will be sterile due to being a freemartin.
Raising twins or multiple calves can bring a whole new set of challenges to an operation. It is important producers are prepared and understand pre-calving and post-calving management techniques to ensure each animal a healthy start. And if managed right, the pros of having multiple births could possibly outweigh the cons, especially with today’s cattle prices. ∆
DR. TERESA L. STECKLER: Extension Specialist, Animal Systems/Beef, Dixon Springs Agricultural Center, University of Illinois
|
|