In my practice I often hear producers complaining about twins, mainly because often the focus is on the problems they can present. However, research done on a twinner population over the last 10 years in the U.S. found there to be a definite economic benefit with twins. So it is important to look at both the positive and negative aspects that come with these double deliveries.
There is no doubt twins can be a positive if they both arrive alive, are the same sex and you have an extra cow to foster one of the calves. But we all know the opposite — twins coming malpresented (mixed up), then you finally get them out (with or without veterinary assistance) both are dead and the cow doesn’t clean and becomes a problem to rebreed. If we can minimize the bad scenario and come up with more positives, twins would be welcome. Keep in mind they will always require more care, attention and management skills.
The original British breeds rarely twinned but with the advent of the exotics, better nutrition and other factors, twinning occurs about eight per cent in Simmentals, Charolais and Holsteins. This creates a lot of extra calves, which if they reach weaning, can definitely improve the bottom line. The key is getting them out alive, grafting one to another cow and then getting the cow rebred. Fortunately twinning has decreased with the red and black Simmentals, and even the traditional ones have fewer twins than previously. Twins happen more often than we think in bison. Most orphan bison calves were most likely born as twins.
Dystocias from fetal malpresentation are the biggest reason twins have a lower survival at birth. Twin or triplet lambs and kids are seldom mixed up at birth, yet calves commonly are. When one ponders all the permutations and combinations of all the legs and two heads coming backwards and forwards, it is no wonder mixups occur. In U.S. twinning research, they selected and kept cows with a propensity to twin resulting in more than 60 per cent of cows delivering twins. They knew to watch these cows closely and jump in when problems developed.
In a commercial or purebred operation there are a few clues to help us. Twins can often drag down a cow’s condition so not only should the cows be pulled from the main herd and fed with the heifers where there is less competition but they can also be observed when closer to calving.
Cows produce twin calves because they have ovulated two eggs or an egg has split, resulting in identical calves. Genetically these cows have a high likelihood of doing it again. You often hear farmers say a cow has had three sets of twins in the last four years or she twins every second year. These are very common scenarios. These cows with any past history of having twins likewise should be monitored closer when they calve. If you observe any unusual behaviour at calving, don’t hesitate to get that cow in and check her out. If cows are ultrasounded early at say 50 to 60 days, twins can be picked up by the test and these should definitely be noted and referred back to come calving season.
The most common presentation for twins is one backwards and one forwards. With the backwards presentations the likelihood of a full breech (tail first) is increased and these often require veterinary intervention. These are a great loss if the breech birth is first preventing the second calf from being born and both are born dead.
With breech births, the cows appear in first-stage labour for a long period and often don’t initiate calving quick enough. In calving twins out, remember to follow the legs back to make sure they are from the same calf and the top calf is the one that must come out first. If assisting at calving, remember to routinely check the cow for a twin, especially if a calf is backwards. Twins have a shorter gestation by about a week than a single birth so it is not uncommon to have a higher percentage of twins early on in the calving season. It never hurts to start observing cows one week to 10 days before the first one is due to avoid missing twins.
Having an extra calf earlier is great because there will be opportunity to foster one. If a cow loses one right at calving, rub the placenta on the twin calf to be grafted. If this fails any of the other tricks including placing the skin of the dead calf over the live one can be attempted. This method works very well if an older calf dies and its smell is transmitted to the transplanted calf.
Half the time twins are mixed sex and about 90-95 per cent of these heifer calves will be freemartins (very little development of the female reproductive organs) and will be sterile. Some freemartins you can definitely tell as the external genitalia are different with a real prominent clitoris. Others look normal and may even cycle but will not breed. Because they possess more male influence freemartins will grow very well (like a bull calf). Producers generally will graft the freemartins, often with the fact they were a twin getting lost in the shuffle. A common mistake is selecting a freemartin for replacement status as they will be in the upper 25 per cent for growth in the heifers. Mark their tag well with “Twin” written on it or use a different-colour tag to avoid this mistake. When they are identified in the feedlot, freemartins do better if implanted with the steer implants.
Any cows that deliver twins are more prone to certain clinical diseases. Retained placenta and metritis are the obvious ones. Because they are generally more run down, the immune system is compromised and conditions such as mastitis and ketosis are increased. If the cows are raising both calves at least for the first few days, provide the cow with better-quality feed as well as extra vitamins E, A and D. A selenium shot may help with retained placenta. As mentioned, a higher number will be treated for retained placentas and also watch for signs of depression and/or a fever, which may indicate metritis. Twins often extend the stretching limit of the uterus and it does not contract as well or as fast after calving. This results in fetal membranes not being expelled and the accumulation of micro-organisms in the uterus. This combination combined with intervention at calving can lead to metritis.
With twins being earlier in gestation, the fetal membranes are immature so don’t release as quickly. This is why retained placentas are common in almost all abortions . Research several years ago showed using Gnrh or prostaglandins at two weeks after calving may get these cows cycling earlier and allow them to get bred on time. There will be more open cows after twins or often they will take another cycle to get bred so it is imperative to provide this extra care post-calving.
I would be remiss to not talk about colostrum supplementation with twins. Postnatal survival is lower with twins due to insufficient consumption of colostrum. Perhaps the cow only mothers the first or second calf or simply has not produced enough to supply both calves. During a slow birth, oxygen-deprived calves may be kind of stupid and have a poor suck reflex. This is where an extra supply of colostrum either saved from your herd or using the good-quality commercial colostrum such as Headstart from the Saskatoon Colostrum Company is a real benefit to improving the survival of twins. Even if they both have nursed vigorously, it’s a good practice to split a bag of high-quality colostrum between the two calves.
More pounds of calf weaned per cow exposed are definitely possible if more twins are saved. Many of the negatives can be counteracted with good management and a little more work. If purchasing twin bulls for breeding, keep in mind birth weight is not relevant and they will not have more of a propensity to twin but their heifer offspring will.
It’s better to pamper twins as we can’t really prevent them and saving them results in more pounds of beef. Here’s to a great calving season and no lost twins.