If cows appear thinner than the rest of the herd, especially in heifers, that can be a clue they are carrying twins. If an ultrasound exam is carried out early enough in gestation, twins can be detected.
Having twins leads to a bigger risk of placenta retention and uterine infections in the dam. Giving birth to twins can damage the reproductive performance of the cow – delaying their return to cycle. Statistics show a cow carrying twins is more likely to abort. There is always a risk of a Freemartin being born.
Twin birth is a complex condition observed in most livestock animals, when the female gives birth to two or more offspring, generally out of the same mating. In cattle, it is a rare condition (3 to 5%) and depends on the genetic background and environmental factors.
“It is estimated that about 2% of beef cattle pregnancies result in twins,” said veterinarian Bob Larson. He explained that twins are the result of either a double ovulation by the cow or an embryo that splits very early in development.
These two calves are contained in the one placenta or afterbirth and being evolved from separate portions of the same egg they are always of the same sex and are identical, or almost identical, in appearance and in general make-up.
While fraternal twins (2 eggs and 2 sperm) are always surrounded in their own sacs and have their own individual placentas, 70% of identical twins may end up sharing a single placenta. Only 1% of identical twins share both a single placenta and a single sac, and this poses significant risk.
Monochorionic-diamniotic twins are identical twins that share a placenta but each develops in their own separate amniotic sac. This is the most common type. Monochorionic-monoamniotic twins are identical twins that share both a placenta and an amniotic sac. This is the rarest and highest risk form of twin pregnancies.
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.
Certain breeds, such as Simmental, Charolais, and Holstein, and also large heifers are more likely to produce twins. On the downside, cows that deliver twins have twice as many problems as cows that only deliver a single calf.
Cows carrying twins had an average gestation length of 274.0 days, which was confirmed to be shorter than their herd mates carrying single calves for 278.7 days.
Producers can identify freemartins by examining the external genitalia. A prominent clitoris and loosely attached or feathery vulval lips are a dead give away. The genital opening may be located down between the back legs toward where the prepuce would be on a bull.
Beef cows are not designed for twins. A cow pregnant with twins is more likely to experience dystocia, or difficultly calving. Even if the calves are born without issues, it's common for one twin to be weaker than the other.
The longest interval between the birth of twins is 90 days, in the case of Molly and Benjamin West, dizygotic (fraternal) twins born in Baltimore, Maryland, USA to parents Lesa and David West (all USA) on 1 January and 30 March 1996.
When these antigens mix, they affect each other in a way that causes each to develop with some characteristics of the other sex. “Although the male twin in this case is rarely affected by reduced fertility, the female twin is completely infertile in more than 90% of cases,” Selk says.
I've been asked by several breeders if it is "OK to breed two half-siblings" (usually, a bull and a cow that share the same sire). The short answer is that there is nothing "wrong" with breeding any two animals of any degree of relatedness, as long as one realizes the potential risks and benefits of the mating.
Identical twin calves are pretty rare.
In cows, this is called dizygous twins, in humans we call this fraternal twins. Less than 10% of cattle twins are monozygous, or “identical” twins. So even if you have two female or two male calves that look the same, odds are they probably aren't identical twins.
Twins require extra milk to help them grow and round out. A ranch cow can sustain two calves for a while with supplemental help such as milk replacer being fed to the calves as well. This creates another daily chore for the rancher to mix and feed milk bottles to the twin calves.
Twinning rates in cattle vary significantly, up to 0.5% in some cases or even more in Euro breeds. Twins can be a management challenge for many reasons. In poorer conditioned cows, metabolic disease including hypocal and preg tox, leading to downer syndrome can be an issue in very late gestation.
“Progesterone levels can be influenced by high feed intake – it increases blood flow through the liver and subsequently reduces the amount of progesterone in the blood.” This reduction in progesterone is proven to increase the likelihood of double ovulation and the conception of dizygotic (non-identical) twins.
Freemartinism. Development of the reproductive tract is compromised in about 95% of female calves born co-twin to a male. Affected calves are called “freemartins.” (The origin of the term is not known.)
We can't stress enough how rare it is for a cow to give birth to triplets. It's only a 1 in 105,000 chance that it happens in the first place, and when it does, many of the babies end up dying. For the ones that do survive, it's not likely that the mom will accept and take care of all three as her own.
Early signs of a twin pregnancy include severe morning sickness, quick weight gain, and more breast tenderness. You may also notice an increased appetite or extreme fatigue. Plus, those who have a twin pregnancy may begin showing sooner.
A twin pregnancy with two placentas and two amniotic sacs is the optimal twin pregnancy, as each baby has its own nutritional source and protective membrane. One placenta and two amniotic sacs. In pregnancies with one placenta and two amniotic sacs, you will definitely have identical twins.