Symposium Uses Technology to Attack twoPLUS Initiative
By MICKY BURCH
Sheep Industry News Contributor
(Sept. 1, 2012) With the first anniversary of the “twoPLUS” initiative in the books, goals are starting to become realizations. Ewe lamb retention saw an increase in some areas of the United States in 2011, according to the National Agricultural Statistics Service, and there is growing interest in raising sheep. The National Sheep Symposium, held July 27-28 alongside the Center of the Nation – National Sheep Improvement Program Sale in Spencer, Iowa, concentrated on using technology to attack the “Let’s Grow with twoPLUS” initiative. A passionate slate of speakers described practical ways for producers to meet twoPLUS goals and offered cutting-edge ideas that may be useful in the future.
Event coordinator Dan Morrical, Ph.D., Iowa State University, stressed the importance of three minerals to increase lambs born and baby lamb survival: Vitamin E, Selenium and Iodine. He encouraged producers to check feed tags because the concentration of Vitamin E is usually too low. Vitamin E interacts with Selenium and is a factor in white muscle disease, so it’s important in times of stress, like late gestation. In addition to white muscle disease, Selenium deficiencies are also responsible for reproductive failure, embryonic mortality, poor suckling reflex, reduced growth and decreased disease resistance. It’s also indirectly associated with hypothermia/goiter. Morrical recommends force feeding Selenium because it’s needed year-round. Iodine, he said, contributes to basal metabolic rate/hypothermia, goiter, fetal development, still births and weak lambs. Unless an operation is close to an ocean, he said, producers need to incorporate Iodine into their sheep diet.
Kreg Leymaster, Ph.D., U.S. Meat Animal Research Center (USMARC), Clay Center, Neb., presented new information about Ovine Progressive Pneumonia Virus (OPPV). Affecting sheep for life, OPPV results in ewes that are highly unlikely to lamb, wean 8-percent fewer lambs and produce 20-percent less litter weaning weight per ewe exposed on an annual basis. OPPV affects the lungs, central nervous system, lymph nodes, joints and mammary glands of sheep. Studies suggest 36 percent of U.S. flocks have affected animals, while 24 percent of all animals tested were infected with the virus. USMARC research identified a gene associated with OPPV and DNA susceptibility testing is now being conducted. With the new testing, breeding stock can be selected for reduced OPPV susceptibility. Removing sheep with susceptible versions of the gene is expected to lower the incidence of OPPV infection in sheep flocks.
Jim Miller, DVM, Ph.D., Louisiana State University, reported dewormer resistance is common and a fresh approach to parasite control is needed. Miller said ewe immunity to parasites wanes during birth and lactation;lambs don’t develop parasite immunity until they are four to six months old. Due to an over-reliance on anthelmintics, worms developed the ability to survive treatments at recommended dose rates.
“Worms that are resistant survive and pass on their resistant gene,” Miller explained. Treatment at frequent intervals (six times per year or more), treating all animals at the same time, treating and moving to a clean pasture, and under dosing are all factors in worm resistance.
To overcome the issue, Miller recommended proper dosing and drenching techniques, administering drugs orally, restricting feed intake 24 hours prior to treatment and quarantining and deworming new sheep to your place. He also recommended selective treatment of individuals based on fecal egg count, body condition score, dag (dirty rear end) score, reduced weight gain, weight loss and bottle jaw. Additional methods for parasite resistant Miller suggested include breeding for resistance, monitoring infection levels through eye-lid (anemia) tests, culling infected animals, deworming individuals as necessary, managing stocking rates and monitoring weather conditions.
Raising more sheep with the same resources was the topic of Mike Caskey’s talk. The Pipestone Lamb and Wool Program coordinator identified key resources to meet this goal, including feed, labor and facilities. To avoid feed waste and over feeding, producers should meet nutritional requirements – but not exceed them – by using feeders that reduce waste, and do rotational and timed grazing on pastures and crop residue. The majority of labor is spent feeding, lambing and handling sheep, Caskey reports. To decrease labor, use low-labor feeding systems (fence line feeders, self feeders, automatic waterers, etc.), implement shorter planned lambing periods more times per year and invest in good facilities, including a sheep working chute and lambing area. Ideally, lambing barns should be between 32 and 40 degrees F; have adequate ventilation; include drop, lambing, grouping and milk replacer pens; and have multiple walk-through gates so shepherds only have to go a short distance when moving families to lambing and grouping pens.
Using breed resources to generate more lambs in commercial settings was the focus of Leymaster’s second presentation. Characteristics of a profitable commercial ewe flock are sheep that don’t require individual attention; ewes that are healthy, long lived, give birth to multiples unassisted and bond strongly with their lambs; and lambs that thrive with little to no intervention. He recommended crossbreeding four breeds to create prolific ewes: Romanov, Finnsheep, Polypay and Katahdin. For increased growth and carcass traits of progeny, he suggested using terminal breed sires like Suffolk or Texel to create heterosis. Complementarily, he said, takes advantage of the strong points of breeds and can be accomplished with either a first-cross terminal sire system or a two-breed rotation terminal sire system. A composite breed, he concluded, is a new breed formed by crossing two or more breeds, then selecting within the new crossbred population.
Keith Inskeep, Ph.D., West Virginia University, presented on successful use of sheep CIDRs to increase out-of-season breeding and why embryo loss occurs. Approved in October 2009, a CIDR delivers progesterone to a ewe in response to the introduction of a ram. Mature ewes need to be in good body condition and be isolated from the ram for at least a month prior to breeding for optimum results. The length of the sheep breed’s breeding season is a limiting factor for use of CIDRs. The ewe-to-ram ratio when using CIDRs is recommended at 18:1. Research has shown an increased response during the first service period when CIDRs were used. However, ewe lambs and lactating ewes didn’t respond well to the use of a CIDR. Once ewes are bred, Inskeep said, embryonic and fetal losses occur throughout gestation. Approximately 3 percent to 4 percent of embryos are lost every 20 days in ewes that were pregnant at day 25. Partial losses, however, are greater than complete losses.
Accelerated lambing, Richard Ehrhardt, Ph.D., Michigan State University, said, is a system that decreases the lambing interval to less than 12 months, creating multiple birthing periods and potentially increasing production per ewe. It also offers the opportunity to produce lambs year round to build lucrative markets. Essentially, accelerated lambing removes four months of maintenance feeding and can produce the same number of offspring per year with fewer ewes.
There are two accelerated lambing systems: the eight-month system creates three lambing periods in two years and the STAR system that creates five lambing periods in three years. In order to accommodate labor availability or target specific markets, “either system can be manipulated by photoperiod and/or hormone therapy,” Ehrhardt said. He noted that a higher plane of nutrition is required for ewes over the course of a year because they’re in a more productive state a greater portion of the time.
Dave Notter, Ph.D., Virginia Tech University, talked about genomics and marker assisted selection tools for breeding better sheep. Genomics helps producers identify carriers of undesirable recessive alleles at birth so animals can either be culled or planned matings can be made to produce non-carrier offspring. Still, success has been limited.
“The early intent was to find major genes and causal mutations,” Notter said. “Interesting regions of the genome have been identified, but repeatability and validation has been a problem.”
Researchers are finding genomics is more directly applicable as a within-breed selection tool rather than across breeds. Notter suggests using the results of within-breed genomics as an estimated breeding value (EBV). “Molecular EBVs have value in identifying superior animals,” Notter said, especially younger animals. “They’ve reduced the need for – and cost of – progeny testing.” Still, he reminds producers they are one tool among many for genetic improvement.
By the Numbers
Erica Rosa-Sanko, Livestock Marketing Information Service, gave a talk about the sheep industry’s long-term economic outlook. Her first words of advice were to do more with less; one way is to produce more lambs with the same number of ewes. She also said the current market environment is likely going to be the “new normal,” so producers will have to figure out how to create profitable margins with higher feed costs, breakevens and prices amongst volatility like drought.
Rosa-Sanko also stressed the consumer is ultimately the person eating the product. That being said, she explained current market conditions are on account of weight and quality issues. To overcome those issues, she recommends adding attributes that increase product demand and total value.
Improving lean meat yield of the U.S. lamb crop was the topic of Cody Hiemke’s presentation. Hiemke, Niman Ranch Lamb program manager, started by pointing out that on June 30, 2012, 38.9 percent of graded lambs were Yield Grade 4 or fatter. Though there are multiple reasons for the excess white meat, he offered constructive advice for each segment of the industry. The message for each segment was consistent: define what your customers and lamb consumers want, and provide as much feedback as possible. He also suggested packers improve reporting and develop economic incentive for suppliers to produce the kind of lamb customers want. He reminded feeders not to simply market corn, but to market value-added, high-quality, appropriately lean lamb. To help producers accomplish these goals, Hiemke suggested using available technology, including ultrasound and EBVs.
By and large, the practical advice, genetic information and hard numbers from the industry created an educational event with numerous take-home messages.