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By Paul Butler

Utilizing high-percentage bison hybrids (sometimes called “ancestry animals”) can add an interesting dimension to your current breeding program. Because of the diverse combinations and genetic variations, high-percentage bison hybrids can be even more exciting than breeding proven Beefalo cattle. There are, however, a number of things to keep in mind if you are considering adding high-percentage bison hybrids to your breeding program, either through natural breeding or frozen semen.

In any discussion of high-percentage bison hybrids, we need to define the terms we are using. For our purposes, the term “high-percentage bison hybrid” means any hybrid of bison and bovine containing more than 3/8 (37.5%) bison breeding. Most of our discussion here will be based on sires containing more than 50% bison being mated either to Beefalo cows (between 17% and37.5% bison) or to straight bovine cows containing no bison genetics.

Following are some general points of consideration for utilizing high-percentage bison hybrids in your breeding program:

  • High-percentage bison breeding is filled with many uncertainties such as fertility, conception, quality, phenotype, disposition, calving, etc.
  • The current market for even proven high-percentage animals and their offspring is very limited and highly variable.
  • Costs associated with animals, semen, and related equipment can be substantially higher than for proven Beefalo cattle.
  • Two bison hybrid animals or their offspring can be very different in terms of amount of bison phenotype, fertility, quality, and temperament (even when produced from the same or similar matings).

Remember. . . when you are breeding high-percentage bison hybrids, you are involved in experimental breeding. You must be willing to accept higher levels of infertility, abortions, and short-term pregnancies, stillbirths, rebreeding problems, etc. Some specific observations about high-percentage animals and the breeding of these animals are listed below:

  • The greater disparity between the percentage of bison in the animals to be mated, the greater the odds are against producing viable, fertile offspring.
  • There seems to be some correlation between the amount of bison phenotype and the handling characteristics of the animal. “If it looks like a buffalo, it acts like a buffalo” is a rule-of-thumb that some breeders use.
  • There seems to be some correlation between the amount of bison phenotype and the level of fertility in bison hybrid males.
  • Gestation lengths in high-percentage bison can be quite variable.
  • There can be exceptions for individual animals to any of the guidelines presented here.

Breeding High-Percentage Bison Sires to Low-Percentage Bison Cows or to Straight Bovine Cows

One of the most common matings is between 75% bison sires and straight bovine cows. Two other similar matings are between 100% bison sires and bovine cows and matings between 75% bison sires and low-percentage Beefalo cows (17-30% bison). Most of the information presented is specifically about breeding 75% bison bulls to domestic cows, but is also pertains to breeding 100% bison sires to bovine cows or to low-percentage Beefalo. Listed below are some of the problems that can occur when making these types of matings:

  • Low conception rates
  • Higher levels of early embryonic loss. This is characterized by cows that conceive, miss one to four heat cycles, then show heat again.
  • Higher levels of later-term abortions (often seen around the 5 th or 6 th month of pregnancy).
  • Possible development of polyhydrominos condition. Commonly called “hydrops”, this is basically a partial rejection of the fetus by the mother, resulting in excess buildup of amniotic fluid in the uterus. This condition can range from mild to severe. In severe cases, the result can be the loss of both the fetus and the cow.
  • Possible development of a type of protein poisoning. Here again, this is the result of a genetic disparity between the fetus and its mother. This condition usually results in one of three scenarios: 1. The cow aborts the fetus. 2. The cow aborts the fetus and subsequently dies (usually a few days after the abortion). 3. The cow dies.
  • Possible severe calving problems. Sometimes a mating results in extreme levels of hybrid vigor in the unborn calf. The calf can become very large before the cow is signaled to give birth. This can happen even with normal gestation lengths.
  • Possible non-viable calves. These are calves which are stillborn or which seem very weak when they are born. These very weak calves almost never survive.
  • Problems with the cows rebreeding after delivering a calf from this type of mating.
  • Problems with male fertility in the offspring of a high-percentage bison hybrid mating. Many times, the bull calves that do result from breeding a 75% bison bull to domestic cows never develop fertility.

There are some ways to improve your chances for success in producing calves from high-percentage bison hybrid sires. Specific observations are:

  • High-percentage bison hybrid sires can vary greatly in the types of problems they produce when mated to domestic cows or to low-percentage Beefalo cows.
  • On average, younger domestic cows seem to have fewer problems with conception, short-term pregnancies, hydrops, etc. than do older cows. It’s possible that the younger cows experience just as many problems as the older cows do but that, because of their age, they’re better able to physically cope with or overcome the problems.
  • There may be some correlation between the breed (or breed crosses) of the cow and the types of problems experienced. Domestic cows of certain genetic makeup may have fewer problems when bred to high-percentage bison hybrid bulls.

Here are some suggestions if you are considering the use of high-percentage bison hybrids in your breeding program:

  • Develop a definite plan. Know exactly what you are trying to accomplish with such breeding. If you are only interested in producing an animal worth a lot of money in one quick, easy step, you should probably reconsider. The chances of actually accomplishing that are very slim.
  • Always keep in mind the traits of economic importance when conducting any breeding program. Fads and percentages won’t help you or Beefalo breeding in the long run.
  • Talk to breeders who have experience with the type of breeding you would like to try. Because of the current state-of-the-art in high-percentage breeding, it’s probably a good idea to get several opinions, since they’re a lot easier to come by than true, hard facts.
  • Talk to breeders who have used the specific sires you may be considering. Their experience may give you some good clues about what to expect if you use the same sires.

Specific Strategies for Dealing with Problems Associated with This Type of Breeding

If conception is a problem

  • Try breeding later than normal . . . possibly 24 hours after standing heat. The semen from some high-percentage bison hybrid sires has a shorter-than-normal viability period. Late breeding may help in matching the viability of the semen with the ovulation of the cow.
  • Breed the cow twice. Use one unit of semen approximately 12-16 hours after standing heat. Use a second unit of semen 20-26 hours after standing heat.
  • Use a unit of other high-quality semen with the semen you’re using from the high-percentage bison hybrid sire. Be sure you have a DNA profile for both sires to assure positive parentage identification. Make sure that the other semen you are using is from a bull you would like as an alternative sire since there’s a good chance the resulting calf could be from him.

If short-term pregnancies or abortion are recurring problems

  • About the only practical solution is to utilize cows with a different genetic makeup.

If hydrops (the development of excess amniotic fluid) is a problem

  • The first challenge is to determine if the cow is actually experiencing a fluid build-up. If you know the breeding date, an experience person can often tell by rectal palpation if the cow is starting to accumulate excess fluid. This is most effective 90-120 days after breeding. Realize that by handling the cow in this manner there is always a chance of causing the cow to abort.

About the only other method of detecting the hydrops condition is to visually observe the girth of the cow as the pregnancy develops. Remember, however, that pregnant cows can vary quite a bit as to their girth measurements, even with completely normal pregnancies. It often helps to have a second opinion when attempting to diagnose hydrops visually.

  • Once you’ve determined that a cow is developing excess amniotic fluid, several treatment options are available:
    • The first option is to start a treatment regimen on the cow as soon as you are sure she is bred. A few breeders have successfully utilized long-term (for the length of the pregnancy) drug therapy. This treatment involves a series of injections every other day for 10 days followed by a 10-day rest period and then another 10-day injection series. The advantage is that bull calves have been born from sires known to cause excessive hydrops. There are three primary disadvantages. (1) Most cows don’t develop severe hydrops when they are carrying a female calf even from a sire known to cause the problem. Therefore, you may be putting a lot of time and effort into a pregnancy that may not develop the hydrops condition anyway. (2) The costs in terms of time and actual money spent on drug therapy can be high. (3) The cow may lose the calf at some point anyway or she may develop severe hydrops in spite of the treatment regimen.
    • The second option after hydrops determination is to use drugs to abort the pregnancy. This option usually results in saving the life of the cow if it’s done early enough.
    • A third option is to drain off some of the excess amniotic fluid. This procedure is delicate and usually requires the services of an experienced veterinarian. Depending on the stage of pregnancy, draining may have to be repeated several times with no guarantee of ultimate success.
    • A fourth option is to use strategies designed to mitigate or lessen the severity of the hydrops condition. Such practices as withholding salt, offering special rations, or reducing water intake sometimes help, depending, of course, on the severity of the problem and the stage of pregnancy.
    • Obviously, a fifth option is to do nothing except monitor the progress of the cow and her pregnancy. Nature will then take its course.

It’s difficult to say which of these is the best option. There is no single solution since what might be best for one cow may not be appropriate for another cow in the same herd. It depends, in large measure, on the attitudes, abilities, and experiences of the people involved. The stage of the pregnancy and the development of other complications are other factors, which should be taken into consideration before deciding which course of action, if any, is to be followed.

If protein poisoning is a problem

  • Here again, diagnosing the problem is the first order of business. Protein poisoning rarely develops prior to the 5 th month of pregnancy. The chances of protein poisoning increase as the length of gestation increases. Protein poisoning may develop in conjunction with or independent of hydrops. The signs of protein poisoning are reduced appetite, general lethargy, depression, gauntness and/or the appearance of dehydration. Usually by the time protein poisoning is diagnosed, the death of the cow is fairly imminent (1/2 day to 4 days). About the only viable option is to treat the cow heavily with strong antibiotics and to try to induce calving or abortion. If the pregnancy is far enough along, it may be possible to perform a C-section on the cow to retrieve the calf. Remember . . .any time too much fluid is released from the uterus of the cow (either by tapping into the uterus through the cervix or by C-section), there is a high risk of inducing shock in the cow.
  • A cow bred to a high-percentage bison hybrid can abort, then develop a type of protein poisoning or septic poisoning. About the only chance to save the cow is immediate treatment with high levels of antibiotics.

If the problem is large calves

  • Sometimes a cow may be rectally palpated and the size of the calf can be determined by feel. This evaluation can help guide your decisions in handling late-stage pregnancies. The three options for suspected large calves are: (1) Use drugs to induce calving. If the breeding date is known, it may be possible to use this method to get the cow to calve before the calf gets too big. CAUTION . . . don’t try this too early because you will be decreasing your chances of getting a live calf. An advantage of induced calving is that it narrows the time window when the cow will calve. This allows for closer monitoring of the calving process. (2) Plan a time and do a C-section on the cow. (3) Closely monitor the cow so that when she begins to go into labor, you can be ready to assist if needed.

If the problem is stillbirths, non-viable calves, or infertile offspring

  • About all you can do is try again next year.

In summary, if you’re thinking about using high-percentage bison hybrids,

  1. Develop a plan and determine the amount of risk you are comfortable with
  2. Do your homework on the potential sires you may be using
  3. Become mentally prepared. Decide in advance how you will diagnose and handle any problems which may develop

There are two more points to keep in mind when breeding high-percentage bison animals:

    • The more you learn, the more questions you will have, and
    • Just when you believe you’re sure about a rule for high-percentage breeding, you’ll find an exception

GOOD LUCK!