Artificial Insemination in Cattle
There are many management decisions that must be made when choosing how to breed your cattle. The biggest decision is if you prefer to use live bulls or stored semen. If you decide you want to use stored semen on all or part of your animals. This blog will provide more information about artificial insemination and using stored semen for reproductive purposes.
Before we go further in-depth we must first know what Artificial Insemination is. Artificial Insemination is the process of depositing stored semen directly into the uterine body of the cow or heifer. The semen, which is deposited into the cow, has been previously harvested or collected from a donor bull. The semen is then prepared and placed in liquid nitrogen for storage until use
Why Use Artificial Insemination
There are many reasons why a producer would chose to use artificial insemination as part of their breeding program. Artificial insemination can provide a producer with faster genetic improvement within their herd. This can be accomplished by using artificial insemination on first or second calf heifers, which carry the highest quality genetics in the overall herd. The producer can then match these traits with the selected bull that will provide the highest level of genetic improvement within the herd.
Utilizing artificial insemination in all or part of your herd will allow you to decrease your bull related expenses. By decreasing the number of bulls, you will physically need onsite; you will be able to reduce your management input as it relates to bulls. This could be related to nutrition and health care expenses, equipment upkeep and replacement, along with human resources, just to name a few. You will also be able to select from a larger quantity of quality bulls that will improve the genetic potential in your herd at a reduced cost.
You can also reduce disease transfer through artificial insemination. This is achieved through a reduction in physical contact between cows and bulls thus reducing the opportunity for transfer of sexually transmitted diseases.
Knowing if Your Animals Are Ready to Breed
Prior to starting your artificial insemination program, you will need to ensure those animals you are placing under this protocol are, or will be, ready to breed when you are ready. Some indicators of breeding readiness are age, breed, nutrition and management, displaying signs of heat and reproductive tract maturity.
Most cattle in the state of Florida are bred to calve as either 2 or 3 year olds. Some ranches prefer to hold their heifers an extra year and calve for the first time as a 3 year old. This allows them extra time to reach mature weights and ensure that their reproductive system is cycling prior to breeding. Many ranches are very successful breeding their animals to calve as a 2 year old. The decision about at what age to breed is an individual ranch management decision. If you prefer your cattle to calve as a 2 year old, you would need to breed at 15 months of age. Likewise, if you prefer your cattle to calve as a 3 year old, you would need to breed at 27 months of age.
When talking about breeding readiness the breed of the animal plays an important role as to when they reach puberty. Bos Taurus cattle, or cattle of breeds such as Angus, Hereford, Charolaise, Limousin, or Simmental, traditionally mature earlier or at approximately 12-14 months of age. Bos Indicus cattle, or breeds such as Brahman, Brangus, or Braford, traditionally mature later or at approximately 14-16 months of age.
One way many ranch managers and producers have found to reduce the time to maturity for their cattle is through nutrition and management. Cattle should reach 55-60% of their mature body weight at time of breeding. This can be achieved through nutrition. One study indicates by early weaning, weaning at 3 months of age, and providing heifers a concentrate feed equal to 3.5% of their body weight, on a regular basis, can reduce the days to maturity (https://edis.ifas.ufl.edu/an305).
Knowing how to recognize the signs of heat is one of the best indicators of breeding readiness. Signs of heat could include mounting, vaginal discharge, pacing, use of a detection patch just to name a few. When these signs are recognized, the animals are exhibiting that they are ready for breeding. Cattlemen should ride their herds at least twice a day for heat signs. When signs are recognized, those animals should be bred 12 hours later. The AM/PM rule follows this philosophy. If you see an animal in heat in the morning you should breed in the afternoon and vice versa.
A newer technology that has come forward is reproductive tract maturity scoring. This technology evaluates the uterine horn size and tone, ovarian structure, weigh of the animal and body condition score. Each area is assigned a score which provides the overall score indicating if the animal is ready for breeding. This technology is provided as part of the “Know Your Heifer” program being offered by Dr. Mario Binelli.
Handling Semen Properly
When using artificial insemination for breeding it is of upmost importance to handle the semen properly. Not doing so can substantially reduce the viable sperm available for breeding. When removing the semen straws from the tank prevent the unused straws from being above the semen tank neck for more than 5-8 seconds. Every second the straw is above the neck of the tank can reduce the efficacy of the semen in that straw. The technician should readily remove the semen straw from the tank using tweezers and place the straw in the prepared warm (90°) water bath. The semen should be thawed for 30-60 seconds prior to insertion. Once the semen straw has been removed from the warm water bath, it should be dried with a clean towel and protected from extreme temperatures. At that point, the semen straw is then loaded into the artificial insemination gun and the end is cut squarely. The sheath is then placed over the gun and you are ready to inseminate the cow.
If you are using artificial insemination to breed an animal, you want to ensure the animal is restrained prior to breeding. There are several restraining techniques can be used, such as a chute, head catch, or alleyway, just to name a few. This is to protect both the animal and the technician during the breeding process. Prior to preparing semen for insemination, you will want to ensure you prepare all the equipment and supplies needed for the process. Once all other equipment is prepared and ready, select your desired semen straw and prepare it for insemination as previously discussed. Once the semen is ready for insemination, you will need to clean the vaginal area with a clean paper towel to prevent any contamination and/or infection. During the breeding process you will use a recto-vaginal method for insemination. This process is when one gloved and lubricated hand is inserted into the rectum and is used to help guide the artificial insemination gun through the breeding process. Once the hand is inserted and the cervix, which feels like a turkey neck with several rings, is located the artificial insemination gun is inserted into the vagina at a 30 – 40° angle to avoid access into the bladder. While using the hand in the rectum, hold the cervix and guide the gun through the rings of the cervix and just into the uterus. You do not want to enter the uterus more than 1-2 centimeters. Once the gun is just into the uterus, you will push the plunger on the artificial insemination gun to deposit the semen into the uterine body. It is essential not to go too far into the uterus, as you do not want to deposit the semen into one of the uterine horns. Doing so could result in an unsuccessful breeding.
In conclusion, many factors can affect pregnancy rates within the herd while utilizing artificial insemination. It is strongly suggested to discuss this decision with veterinarians, extension agents, artificial insemination technicians, and also other ranchers prior to starting an artificial insemination program regarding the advantages and disadvantages. Prior to starting any breeding protocol ensure your animals are ready for breeding. Ranchers need to know signs of heat as one way to ensure breeding readiness and also to know when to breed animals by artificial insemination. When breeding, ride the herds a minimum of two times per day for signs of heat. Following proper semen handling protocols is essential to prevent reduced semen efficacy. When investing in artificial insemination, use an experienced technician to increase the amount of animals successfully bred. It is important to plan your breeding protocols prior to the breeding season. If using artificial insemination, synchronization protocols are also frequently paired with the breeding process. For more information on synchronization protocols and more on beef cattle reproduction visit the Alvin C. Warnick Reproductive Management Video Series online at https://sfbfp.ifas.ufl.edu/Publications/Reproductive%20Management%20Video%20Series.shtml
If you have any questions feel free to contact your local extension agent.