WEEKLY Ag Update By Nathan Anderson 1/22/2019 First Calf Heifer Nutrition A lot of the time, we treat our first calf heifers (or first calf cow) the same as the rest of the cowherd, sometimes even with them running in the same pasture. However, there is a major nutritional difference in the nutrient requirement and nutrient uptake between a first calf heifer and a mature cow. When a heifer calves for the first time, most likely she has not reached her true mature weight and is still growing. Therefore, she is not only trying to raise a calf but also deposit protein and flesh onto her own frame. A mature cow still has a healthy protein requirement, but only to replace the protein turnover within the body and is not concerned about depositing any more protein. Another issue is the heifer does not have the capacity to consume as many nutrients as a mature cow, again due to size. For example, a 1200-pound lactating cow will consume approximately 30 pounds of dry matter daily, but a 1050-pound lactating heifer can only consume approximately 24.6 pounds of dry matter daily. Since she is still growing, her nutrient requirements are similar to the mature cow. If the heifer were still gaining a half a pound a day her nutrients requirement would be 2.7 pounds of crude protein (CP) and 16.3 pounds of total digestible nutrients (TDN) daily. The mature cow would require 3 pounds of CP and 17.6 pounds of TDN. Now that she is consuming less dry matter and her nutrient requirement is similar to the
mature cows then that means that, the diet s nutrient density must be higher for the heifers. In this example the heifer s ration would need to be 11% CP and 66.3% TDN and the mature cow would need a ration to be 10% CP and 58.7% TDN. The major difference between the two animals is the amount of supplement required to meet nutrient requirements. If both animals were consuming a forage that was 9% CP and 56% TDN, the mature cow would need to be supplemented 1.67 pounds of a 20% cube daily. Whereas the first calf heifer would need to be supplemented 4.14, pounds of the same supplement daily. Separating your first calf heifers from the mature cows during lactation can be difficult if the addition- al pasture space is not available, but it would be a management decision that would allow you to focus your supplement costs on the animals that require the most attention. By doing so, you will minimize nutritional deficiencies while setting your heifers up for a long successful life in the herd. For help with any heifer development plans or questions please contact your county s OSU Extension office. Clostridium tetani Tetanus or Lockjaw is a condition caused by a neurotoxin produced by the bacteria Clostridium tetani. The neurotoxin is very potent. Most animals are susceptible to the toxin, but some species are more sensitive than others. Birds seem to be very resistant, but horses and sheep seem very sensitive. The disease is usually fatal. The characteristics of the disease include increase sensitivity to stimulation, contracting muscles, and convulsions.
C. tetani form spores that may persist in the soil for many years. The bacteria may also be found in fecal material of many animals. The spores are very resistant to many disinfectants. They are also resistant to high temperatures but can be destroyed by extremely high temperatures (2390 F for 20 minutes). C. tetani usually enters the animal by a deep puncture wound. The bacteria may enter the reproductive tract following uterine infections. Other ways to introduce the pathogen are through farm procedures such as castration, dehorning, shearing, and tail docking. Once the bacteria enter the body of an animal, they will only proliferate under the right situations. The most important condition is low tissue oxygen levels. This may take 1 to 3 weeks or may take several months. Many times, the original wound has healed long before clinical signs of tetanus are seen. The organism produces three toxins. The most important is a neurotoxin called tetanospasmin. This toxin reaches the central nervous system by passing up the peripheral nerves. The toxin prevents the inhibition of contraction of muscles which results in muscle spasms. The second toxin produced is called tetanolysin, which is thought to cause tissue necrosis. This creates a good environment for the proliferation of the organism. The third toxin is also a neurotoxin. The initial clinical signs of the disease are muscle stiffness and muscle tremors. One of the first signs seen is the prolapsing of the third eyelid. The third eyelid can be induced to prolapse by tapping between the eyes or raising the head. This followed by generalized stiffness, problems walking, restriction of jaw movement (lockjaw), raised tail (pumphandle), erect ears, nostrils dilated, and exaggerated response to stimuli. Constipation, failure to urinate, and bloat may be seen. As the disease progresses, the muscle constriction intensifies, and animals may have a sawhorse stance. Animals usually fall to
the ground when attempting to walk. Animals will convulse when stimulated but eventually the convulsion becomes spontaneous. Severely affected animals are recumbent with the neck and legs extended. Animals die due to asphyxiation due to respiratory failure. If a veterinarian finds the original site of the infection, he/she may attempt to culture the organism to confirm the diagnosis. However, culturing the bacteria is difficult. Most veterinarians make a diagnosis of tetanus based on clinical signs. Treating an animal with tetanus is difficult and often unrewarding. The goal of treating this dis- ease is to eliminate the bacteria, neutralize the toxins, control the muscle spasms, supportive care, and stimulate immunity. Eliminating the infection begins with administering large doses of antibiotics. If the wound is found, it will need to be cleaned and any dead tissue removed. If the disease is diagnosed early, tetanus antitoxin should be given to neutralize the neurotoxin. Animals should be kept in a dark well bedded stall. The area should be quiet to keep stimulation to a minimum. Sedatives may be necessary to control muscle spasms. Animals may not be able to drink and eat, so producers may need to administer food and water by a feeding tube. Administering a tetanus toxoid to stimulate immunity may be beneficial. Prevention of tetanus begins with good hygiene. All instruments used for castration, tail docking, and shearing should be disinfected. The surgical site should be disinfected. When using bands to castrate, the bands should be disinfected and once in place, they should be sprayed with an iodine base disinfectant. All procedures should be done in clean environments. Once procedures are completed, animals should be placed on pastures.
Avoid keeping animals in dry lots where dirt and debris may contaminate the surgical sites. Vaccination plays an important role in protecting animals against tetanus. Since two different types vaccines are available, producers may be confused on which one to use. Tetanus antitoxin (TAT) should be used when immediate protection is needed. TAT provides protection, but it only lasts a few weeks. A tetanus toxoid should be given to stimulate an animal s immune system. Once an animal has been vaccinated, they should be protected if exposed to C. tetani. Young animals should be vaccinated initially with 2 doses of tetanus toxoid. The vaccinations should be 4 weeks apart. The animals should receive an annual tetanus toxoid vaccine once a year after the initial 2 dose program. Tetanus in animals is often fatal, so producers will be way ahead to practice good hygiene and vaccinate their animals to protect them from this disease. If producers would like more information about tetanus, they should contact their local veterinarian or County Extension Educator. Cost of Missing a Cycle Cow calf producers are feeling the pinch of tight margins. And now is a good time to dive into the importance of reproductive efficiency. Hopefully this article will help focus us on the fundamentals of getting cows bred, getting them on the ground alive and pushing down the scales a little further at the sale barn.
To do the best job we can evaluating our management performance, we need to look at a nonbiased performance measure. The key evaluation tool used to measure how good of a job we are doing get- ting cows bred is the pregnancy percentage. The calculation is very simple and it needs to be calculated every breeding season, fall or spring. One point of consideration is the timing at which this is calculated. It s very common for this process to take place at weaning. This diagnosis can be done much quicker, as soon as thirty days after the bull is pulled, depending on the producer s preference. Even if it required a vet trip out, we can easily recover this cost by lessening our grazing pressure and getting those culls sold at a point where seasonal prices should be stronger. There is another issue that is less discussed. That issue is when in our calving season does the cow calve? If we are targeting a 70 day calving season, it is vastly important that we are calving as many of those cows in the first 35 days as possible. The research illustrates time and time again that the performance of calves that come early in the season is beneficial all the way through the beef production cycle. So what does it cost
to miss one heat cycle? The graphic shows a crude calculation of the gain that we miss out on with cows calving one cycle late. At the end of the day, improved profits are usually a collection of small well thought out production decisions. Now that we are entering the dog days of this cattle cycle we need to stick to our production fundamentals. The method that we use to improve pregnancy percentage or to tighten our calving window will vary based on the cow herd. It could come from an improved vaccination proto- col, a nutritional change, or even from selection pressure. In any case, calculate the cost accurately and understand the potential impact on the cowherd and the bottom line. Oklahoma State University, as an equal opportunity employer, complies with all applicable federal and state laws regarding non-discrimination and affirmative action. Oklahoma State University is committed to a policy of equal opportunity for all individuals and does not discriminate based on race, religion, age, sex, color, national origin, marital status, sexual orientation, gender identity/expression, disability, or veteran status with regard to employment, educational programs and activities, and/or admissions. For more information, visit https:///eeo.okstate.edu.