COCCIDIOSIS: A THIEF AT WORK

High Noon Feeds has experimented for years to perfect the best program for feeding animals while controlling the coccidia protozoan that robs them from achieving maximum performance through all stages of growth, development and gestation. Control is the key to managing a coccidia outbreak in all animals being stressed during any season of the year. High Noon Feeds formulates its feed products with the ionophore, Bovatec. We vary the grams of Bovatec in our feeds to match the stage of development with anticipated consumption of the animals being fed our products to stay within the legal limits as regulated by the USDA. Bovatec and rumensin are ionophores meaning that they alter the volatile fatty acid production (VFAs; acidic, proprionic and butyric acids) ratio by protozoa in the rumen. These products do this by increasing proprionic acid that is more readily converted to body weight gain and growth from the feeds fed thus increasing feed efficiency. The added benefit of these two products is that they also interrupt the life cycle of coccidia larvae by destroying them before they become destructive to the cellular lining in the small intestine of the ruminant. The small intestine is where nutrient absorption generally takes place. If a large load of coccidia infects the tissue lining of the small intestine, absorption efficiency decreases severely and the animal passes undigested feed particles along with blood in its stools. When you see animals with stools that look dark, runny and have some bloody discharge then you have a coccidia outbreak. At this point, if you are unfamiliar with dealing with this situation you should consult your veterinarian to confirm diagnosis and get recommendations for treatment.

Decoxx does not alter rumen VFA production however, it is an effective coccidiostat that also interrupts the life cycle of coccidia larvae.

Because of the added benefits gained by using Bovatec as a medication agent for coccidia while yet improving feed efficiency High Noon Feeds formulates all of its feeds using this product. We do not alternate between Decoxx and Bovatec in our feed formulations because we have observed added stress to the animals when switching them from one medicated additive to the other that resulted into a coccidia outbreak. Valuable animals being fed to maximize show ring performance cannot afford this type of added stress in their development on their way to becoming a champion! High Noon Feeds recommends a comprehensive program feeding ewes and lambs Bovatec in their rations along with regular fecal checks for invading parasites and use of appropriate antheleminics.

Genotype Considerations for Scrapie Susceptibility

DNA mutation testing for scrapie resistance has finally received acceptance by the Department of Agriculture’s Animal Plant Health Inspection Service (APHIS) as an acceptable means for flock control of this fatal nuerodegenerative disease in sheep and goats. That is good news for breeders because now an easy method for control of the genetic inheritance for susceptibility is easily obtained from a small sample of blood taken from an animal.

However, susceptiblity testing at codon 171 may not be enough. In 2002 scrapie positive animals (sheep) were discovered that DNA tested QR at codon 171. What does that mean for breeders? It means that if you are testing replacement and/or sale animals for resistance inheritance additional testing of QR diagnosed sheep is needed to insure scrapie resistance. Thus far it has been determined that sheep testing positive for scrapie and possessing a codon 171 genotype of QR have also been shown to be AV at codon 136. Sheep that had been diagnosed with scrapie and found to be QQ at codon 171 always have an AV at codon 136. To date, no animals with a codon 171 test of RR has ever been diagnosed with scrapie. Given this latest development all animals that test QR at codon 171 should be re-tested to determine their genotype at codon 136. The preferred genotypes that seem to yield scrapie resistance are AA/RR, AA/QR (codon pairs are generally listed in numerical order).

Why is the codon 136 mutation, V, important to susceptibility of scrapie if codon 171 is QR? Codon 136 mutations conferring susceptibility to scrapie appear to be linked to mutations at codon 171 (QR) and dominate over that genotype. No animals have ever been found with a genotype of AV/RR suggesting that the inheritance of the V mutation at codon 136 is linked to inheritance of the Q allele at codon 171. To date, there is still no need to test US sheep for their genotype at codon 154. We will continue to update our customers on new developments with the correlation of genotypes and their affect on scrapie susceptibility, as they become available.

Bottom line: If your breeding objective is to raise sheep that are genetically resistant to scrapie and you have replacement breeding animals with a genotype at codon 171 of QR then have the sheep’s DNA tested (their DNA should still be available at your commercial provider) for the genotype at codon 136. If the codon 171 animals are QR and the codon 136 has a genotype of AV then you have a serious decision to make regarding your commitment to cull potentially susceptible animals from your breeding program. If animals test AA/QR then they may not be susceptible to scrapie and can be kept for breeding purposes in your flock or herd. New testing methodologies are coming soon that will allow genotype determination at codons 136 and 171 to be done simultaneously. Contact your favorite service provider and they will be happy to assist you with your testing needs.