Many producers are faced with making several tough decisions on a daily basis. Regardless of managing a herd that is large or small, one of the decisions that must be made is whether to purchase or raise your replacement heifers. One of the biggest considerations is whether you have the resources such as land, labor, and finances to support raising your own replacements. When raising replacements, you want to make sure you have accurate records for individual cow/calf pairs. The information in the records will be very useful when management decisions need to be made. Another consideration would be if you are willing to have a low-birth-weight bull to breed to the young heifers or will you be using artificial insemination (AI) to breed all or part of your heifers and/or young cows.
If you decide to raise your own replacements, you will need to evaluate your operation. Are you able to grow this animal so they reach a minimum of 65% of their mature weight at puberty? On average most cows would be between 650 – 750 pounds at puberty or 14-15 months of age. This will produce offspring at an average age of 2 years. Puberty is a function of the animals’ genotype, age and weight. Considerations should also be made for the breed of animal, recognizing that larger breeds will mature later than smaller breeds. 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. If you are not able to grow your replacements within that time frame or have an undefined breeding season you may consider waiting and breed your animals to calve at 3 years of age.
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 them 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. Other 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 were going to calve as a 2-year-old, you would need to breed at 15 months of age. Likewise, if you planned to calve as a 3-year-old, you would need to breed at 27 months of age.
One way many ranch managers and producers have found to reduce the time to maturity for their animals is through nutrition and management. Cattle will need to be 65% 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 can reduce the days to maturity.
When selecting replacement heifers for your herd, you want to select more than will be needed. Over time you will need to cull some of those out of the herd for one reason or another. If you don’t allow for extras you are limited on your final selection. When possible, take the time to review the records of the heifers. You want to find heifers with reproductive efficiency, have a high degree of fertility, are structurally sound and have a frame size between a 5 and 6. Some possible problem areas that you may encounter would be unexpected low pregnancy rates from yearling heifers, higher calf losses at calving and low percentage of rebreeding for the second calf.
When raising your own replacements, you should evaluate them on a regular basis to ensure they are meeting your criteria. At weaning you want to keep replacements with heavy weaning weights. This allows them to reach the desired weight at puberty with fewer inputs. Evaluating heifers as a yearling will allow you to ensure that they have reached the desired weight for breeding and have also reached puberty. After the breeding season, evaluation is important to ensure the heifers are still growing to reach 80-85% of their mature weight at calving while also maintaining their pregnancy. After they have weaned their first calf you will be able to evaluate the quality and size of calf the heifer was able to produce. This is a sign as to the milking abilities of the heifer. Lower weaning weights can be an indicator of low producing mothers.
If you decide to calve your heifers at 2 years of age you should maintain a cow herd that has a mature weight that is suitable for the resources and environment that are available to them. Preconditioning heifers after weaning will ensure weight gain rather than weight loss. Synchronizing heifers can assist in the breeding process. This will allow a tighter calving interval allowing you to know when to watch for heifers having difficulty. Artificial insemination may be a consideration for first calving heifers if you have a smaller herd. This will allow you to make more decisions based on the bull you chose for your animals. A typical breeding season for heifers is 60-75 days and begins 20-30 days prior to the mature cow breeding. Pregnancy diagnosis should be followed up 60 days after the breeding season allowing for the culling of open heifers and cows.
There are many reasons why a producer would choose 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 best 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 also 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.
When managing the young cow nutritionally you want to keep the animals separate from the mature cow herd. These animals are still growing and need more management than the mature cow herd. You will also be able to monitor the herd more closely and recognize problems earlier if they are kept separate from the mature cow herd. The critical nutritional period for first calf heifers is 80 days after calving. This is when the animal can become nutritionally deficient while producing milk for her calf and also trying to continue to grow and support her own body functions. For this reason, first and second calf heifers should calve in at a body condition score of 5 to 7. Supplementation should be provided so they lose no more than one body condition score.
Body Condition Scoring is the least expensive management tool an owner, ranch manager, or worker has. There is no charge for the tool. The only expense is the time it takes to learn how to properly evaluate cattle. There are six locations that evaluators should look at when assigning a body condition score. You should look for the amount of flesh or fat around the back, tail head, pins, hooks or hips, ribs, and in the brisket area. Breed types can influence the fat deposition pattern. Beginners can start evaluating cattle and placing them in one of three categories: thin, moderate, or fat. This is an easier assessment while you are learning how to assign actual body condition score. After you are comfortable with those assessments, you can start practicing placing cattle in an actual body condition score. Scores range between 1 and 9 with 1 being extremely thin and 9 being severely obese. Thin assessed cattle traditionally range in body condition score from 1-3, moderate from 4-6, and fat from 4-9. Body condition score can be very subjective. When two or more individuals are evaluating the same animal, the scores should be no more than 1 point difference from one another. The most common body condition score in Florida ranges from 3-6. Pregnancy and hair length can influence the visual evaluation of body condition score.
Body condition score has been proven to have an economic impact on the cow herd. A typical production cycle is to rebreed or breed in early spring and wean in late summer. Body condition score is directly related to reproductive efficiency, performance, and weaning weight. Studies have shown that as the body condition score increases, so does the conception rate, calving rate, and weaning weight of calves, leading to higher profits.
These young animals are the future of your operation. If you are able to select the animals that fit your operation and manage them well they will be in your herd for years to come.
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