Location: Nutrition, Growth and Physiology2015 Annual Report
Objective 1: Determine the nutrient value and environmental consequences of novel feed products. Component 1: Problem Statement 1A Objective 2: Improve determination of dynamic changes in nutrient requirements as the animal’s physiological status changes to allow for timed nutrient delivery. Component 1: Problem Statement 1A Objective 3: Determine the role of malnutrition during critical periods in developmental programming and epigenetic effects that alter lifetime production potential and product quality. Component 1: Problem Statement 1A Objective 4: Determine metabolic and physiological mechanisms responsible for variation in feed efficiency that is under genetic control. Component 1: Problem Statement 1A Objective 5: Determine age, gender, genetic, and environmental factors that account for variation in feeding activity and growth of swine Component 1: Problem Statement 1C Objective 6: Characterize the response of cattle to changes in environmental temperature with respect to various management strategies and animal risk factors. Component 1: Problem Statement 1C Obective 7: Determine the relationships between ruminal microbial communities, animal genotype, and/or methane production with feed/nutrient use efficiency and/or lactation performance in response to varying nutritional regimens in beef or dairy cattle. Component 1: Problem Statement 1A Component 2: Problem Statement 2B; Problem Statement 2D
Feed costs represent the single largest input in both beef and swine production; however, less than 20% of the feed energy is converted to edible product. Improving the efficiency that feed is converted to animal products has the potential to improve the economic efficiency of animal production while improving the sustainability of animal agriculture. To maximize feed efficiency the correct profile of nutrients are matched to meet an animal’s needs for its current biological status (growth, pregnancy, lactation, previous nutrient history, and disease). In order to provide the correct profile of nutrients, the nutrient composition of feeds and the dynamic nutrient requirements of the animal must both be identified and then synchronized. There is genetic variation amongst animals in their ability to utilize feed. Multiple genes are associated with the regulation of feed intake, and the utilization of ingested nutrients. Differential expression of these genes results in variation of feed efficiency amongst animals within populations, and these genetic differences potentially change the nutrient requirements of the animal. Nutrient status during critical periods of development (fetal and peripuberal) can permanently modify the expression of genes changing the lifetime feed efficiency of an animal. Identifying the role of nutrition in regulating gene expression is needed to develop nutrition management strategies across generations of animals in a production system.
Individual feed intake, body weight gain, back fat depth and loin-eye data were collected on 400 pigs. Six pigs that differed body weight gain at a common feed intake were slaughtered and small intestine tissue, liver, muscle, and adipose tissue were collected to conduct transcriptomics analyses. In addition, small intestine samples were collected for histology and nutrient flux analyses. (Objective 4) Feeding behavior on 234 pigs was measured to test for difference amongst three genotypes. (Objective 5) A system was developed to monitor sow posture and activity and piglet distribution in farrowing crates. (Objective 5) An algorithm to monitor daily feeding behavior of sows was developed. (Objective 5) A predictor of heat stress in cattle was developed using a fractal dimensional analysis of body temperature. (Objective 6) A measure of heat stress was developed using respiration rate across an entire season. (Objective 6) Sustainable systems research was initiated to study the use of cover crops and crop residue for backgrounding calves before finishing them in a feedlot. One-hundred twenty steers were background fed a cover crop planted after corn silage harvest, cornstalks and distillers grains, or in a traditional feedlot. (Objective 1) The efficacy of using beta agonist combined with implants on steer performance and subsequent product quality was tested across 18 breeds. A total of 450 steers were evaluated this year. (Objective 1) Rumen fluid samples were collected on 150 steers to test for relationships between the microbiome and feed efficiency. (Objective 7) One-hundred and forty-six steers were individually fed and evaluated for feed efficiency. Plasma samples were collected to determine the relationship between hormones and metabolites and feed efficiency. At slaughter, 14 steers that had low or high rates of gain at a common feed intake were sampled to conduct metabolomics profiles in plasma, muscle, adipose, and small intestine tissue. (Objective 4) Plasma samples were collected on 480 steers to determine the effect of feeding a beta-agonist (zilpaterol) on cortisol and urea nitrogen concentrations. (Objective 4) Transcriptomics was conducted on the duodenum, jejunum, ileum, mesenteric fat, spleen, and liver of 16 steers that varied in feed efficiency. (Objective 4) Transcriptomics was conducted on adipose and muscle tissue of 12 cows that were either low or high for weight gain after a period of weight maintenance. (Objective 4) Research was conducted on the development of a low cost genotyping panel. (Objective 4) The microbiota of the jejunum, cecum, and colon of 32 steers that differed in feed efficiency was determined. (Objective 7) Individual feed intake and weight change was collected on 199 cows that represent 18 different breeds. (Objective 4) Production records were recorded on 515 cows that had been developed under two different regimens as heifers. (Objective 3) Production records were collected on 259 cows that had experienced different fetal nutrition. (Objective 7)
1. Lysozyme is a suitable alternative to antibiotics in swine nursery diets, and lysozyme ameliorates the effects of a chronic immune challenge. Subtherapeutic levels of antibiotics are used in swine feed as growth promotants, to improve feed efficiency, and to reduce the susceptibility to bacterial infections. As a result, the use of antibiotics improves the profitability of production for swine producers. However, swine producers are currently under pressure to eliminate subtherapeutic antibiotic use throughout the production cycle. Finding safe and effective alternatives to traditional antibiotics will give swine producers viable options in the event that the removal of traditional antibiotics is needed. ARS researchers at Clay Center, Nebraska, determined that feeding an antimicrobial enzyme, lysozyme, to nursery pigs was as effective as traditional antibiotics in increasing growth performance, including growth, nutrient accretion, and feed efficiency. In addition, lysozyme was effective in pigs under a chronic immune stimulation. Lysozyme is an alternative antimicrobial that could be used by swine producers.
2. Beta-agonists such as zilpaterol hydrochloride (ZH) can be used with or without wet distillers grains with solubles (WDGS) to improve animal performance and carcass characteristics during summer months with little to no impact on cattle heat stress. Since 2006, zilpaterol hydrochloride has been approved for use in feedlot cattle; however, there is no research on any interactions between ZH, co-products, and heat stress. ARS researchers at Clay Center, Nebraska, determined that feeding ZH resulted in greater body weights, daily gain, and feed efficiency. There were no differences in heat stress measurements. Zilpaterol hydrochloride can be used by beef producers as a growth promoter without affecting animal susceptibility to heat stress.
3. Cattle that grow faster on similar amounts of feed do not produce more methane than slower growing animals. Methane is produced as a product of fermentation in the digestive tract of cattle. Methane released by cattle represents a loss of feed energy and a source of greenhouse gases. The methane is produced by a specific group of microbes (methanogens). Steers vary in the amount of weight they gain on a given amount of feed. ARS researchers at Clay Center, Nebraska, determined that steers that differed in their weight gain, but ate similar amounts of feed, did not differ in their potential to produce methane, nor did the total level of methanogens differ between the two groups. Methanogens were identified in both the upper (reticulum-rumen complex) and lower digestive tract (colon). Selection for improved feed efficiency in beef cattle does not imply a reduction in methane production.
4. There are shifts in populations of some rumen bacteria associated with feed efficiency. Feed is the primary cost associated with beef production. The digestive system of cattle contains bacteria that ferment the feed which aids in digestion. The nutrient profile that the animal receives is dictated by the fermentation products of the bacteria. The bacterial community will determine what fermentation products the animal will be presented. The relationship between bacterial community and feed efficiency is poorly understood. Using DNA sequencing technologies, ARS researchers at Clay Center, Nebraska, identified populations of bacteria that change in cattle that have different feed efficiencies. The relationship between rumen microbial community and physiology of the digestive tract needs to be considered when measuring feed efficiency.
5. Discovery of genetic markers for temperament. Flight speed is a measure of the time it takes an animal to traverse a certain distance after being contained in a chute and is considered to be an objective measure of an animal’s temperament. As handling cattle is necessary for disease treatment, during breeding seasons, weaning and other various reasons, a calm animal response to handling is important for the safety of both the animal and the handlers. ARS researchers at Clay Center, Nebraska, determined that single nucleotide polymorphisms located on BTA6 that are strongly associated with average daily gain and average daily feed intake are also associated with cattle temperament. Genetic markers associated with feed intake and body weight gain can also be used to select for temperament in animals.
6. Determination of optimum level of glycerin to include in cattle diets. Expansion of the biodiesel industry in the United States has increased the supply of glycerin. Glycerin is energy dense and can be fed to cattle; however, the energy value is not known. ARS researchers at Clay Center, Nebraska, determined that cattle intake decreased when glycerin intake increased. Also, cattle lost less energy in the feces as glycerin inclusion increased in the diet, meaning that glycerin was more digestible than the corn it replaced in the diet mixture. Cattle consuming 15% glycerin retained the least amount of energy and nitrogen. There is a high metabolic cost associated with including glycerin in cattle diets at greater than 10%. To optimize animal performance, glycerin should not be fed at greater than 10% in beef cattle diets. Glycerin is a potential co-product feed in beef production; however, overfeeding glycerin can have a negative effect on animal performance.
7. Corn processing alters odor emission from the urine and feces. Odor and volatile organic compound emissions have been an issue at animal feeding operations, and has become more prevalent as houses encroach upon areas once occupied only by agriculture. These odors are generally caused by odorous volatile organic compounds emitted from feces and urine. Wet distillers grains with solubles (WDGS) are a by-product of ethanol production, and have become a staple in many beef cattle finishing diets. ARS researchers at Clay Center, Nebraska, determined that flux of sulfurous compounds was greater in feces of cattle fed dry-rolled corn than steam-flaked corn diets, but there were no differences when WDGS was included. Flux of volatile fatty acids from urine was greater in cattle fed steam-flaked corn than dry-rolled corn diets, and there were no differences in cattle fed WDGS. Based on these results, the majority of the volatile organic compounds and volatile fatty acid flux from cattle feeding operations is from the urine. Producers can alter the manner in which feed is processed to change odor emissions from feces and urine.
8. The regulation of feed intake in cattle given unlimited access to feed is still largely unknown. Measurement of factors that are involved in the control of feed intake could be used to select cattle for desirable production traits such as feed intake and efficiency of feed conversion to meat. Ghrelin has been identified as a regulator of food intake in some animals. ARS researchers at Clay Center, Nebraska, determined that there was an increase in active ghrelin as feed intake increases, but total ghrelin decreased. There is evidence for genetic contribution to circulating ghrelin. Circulating ghrelin levels may be a potential biomarker for feed intake.
Saatchi, M., Beever, J.E., Decker, J.E., Faulkner, D.B., Freetly, H.C., Hansen, S.L., Yampara-Iquise, H., Johnson, K.A., Kachman, S.D., Kerley, M.S., Kim, J., Loy, D.D., Marques, E., Neibergs, H.L., Pollak, E.J., Schnabel, R.D., Seabury, C.M., Shike, D.W., Snelling, W.M., Spangler, M.L., Weaber, R.L., Garrick, D.J., Taylor, J.F. 2014. QTLs associated with dry matter intake, metabolic mid-test weight, growth and feed efficiency have little overlap across 4 beef cattle studies. Biomed Central (BMC) Genomics. 15:1004.
Lindholm-Perry, A.K., Kuehn, L.A., Freetly, H.C., Snelling, W.M. 2015. Genetic markers that influence feed efficiency phenotypes also affect cattle temperament as measured by flight speed. Animal Genetics. 46(1):60-64.
Freetly, H.C., Vonnahme, K.A., McNeel, A.K., Camacho, L.E., Amundson, O.L., Forbes, E.D., Lents, C.A., Cushman, R.A. 2014. The consequence of level of nutrition on heifer ovarian and mammary development. Journal of Animal Science. 92(12):5437-5443.
Hales, K.E., Foote, A.P., Brown-Brandl, T.M., Freetly, H.C. 2015. Effects of dietary glycerin inclusion at 0, 5, 10, and 15 percent of dry matter on energy metabolism and nutrient balance in finishing beef steers. Journal of Animal Science. 93(1):348-356.
Oliver, W.T., Wells, J., Maxwell, C.W. 2014. Lysozyme as an alternative to antibiotics improves performance in nursery pigs during an indirect immune challenge. Journal of Animal Science. 92(11):4927-4934.
Hales, K.E., Parker, D.B., Cole, N.A. 2015. Volatile organic compound flux from manure of cattle fed diets differing in grain processing method and co-product inclusion. Atmospheric Environment. 100:20-24.
Foote, A.P., Hales, K.E., Lents, C.A., Freetly, H.C. 2014. Association of circulating active and total ghrelin concentrations with dry matter intake, growth, and carcass characteristics of finishing beef cattle. Journal of Animal Science. 92(12):5651-5658.
Hales, K.E., Shackelford, S.D., Wells, J., King, D.A., Hayes, M., Brown-Brandl, T.M., Kuehn, L.A., Freetly, H.C., Wheeler, T.L. 2014. Effects of feeding dry-rolled corn-based diets with and without wet distillers grains with solubles and zilpaterol hydrochloride on performance characteristics, and heat stress in finishing beef steers. Journal of Animal Science. 92(9):4023-4033.
Freetly, H.C., Lindholm-Perry, A.K., Hales, K.E., Brown-Brandl, T.M., Kim, M.S., Myer, P.R., Wells, J. 2015. Methane production and methanogen levels in steers that differ in residual gain. Journal of Animal Science. 93(5):2375-2381.
Myer, P.R., Smith, T.P., Wells, J., Kuehn, L.A., Freetly, H.C. 2015. Rumen microbiome from steers differing in feed efficiency. PLoS One. 10(6):e0129174.
Cushman, R.A., Tait Jr, R.G., McNeel, A.K., Forbes, E.D., Amundson, O.L., Lents, C.A., Lindholm-Perry, A.K., Perry, G.A., Wood, J.A., Cupp, A.S., Smith, T.P., Freetly, H.C., Bennett, G.L. 2015. A polymorphism in myostatin influences puberty but not fertility in beef heifers, whereas µ-calpain affects first calf birth weight. Journal of Animal Science. 93(1):117-126.
Keele, J.W., Kuehn, L.A., McDaneld, T.G., Tait Jr., R.G., Jones, S., Smith, T.P., Shackelford, S.D., King, D.A., Wheeler, T.L., Lindholm-Perry, A.K., McNeel, A.K. 2015. Genomewide association study of lung lesions in cattle using sample pooling. Journal of Animal Science. 93(3):956-964. DOI: 10.2527/jas.2014-8492.
Miles, J.R., Vallet, J.L., Ford, J.J., Freking, B.A., Oliver, W.T., Rempel, L.A. 2015. Contributions of the maternal uterine environment and piglet genotype on weaning survivability potential: II. Piglet growth, lactation performance, milk composition, and piglet blood profiles during lactation following reciprocal embryo transfers between Meishan and White crossbred gilts. Journal of Animal Science. 93(4):1555-1564.
Schneider, J.F., Miles, J.R., Brown-Brandl, T.M., Nienaber, J.A., Rohrer, G.A., Vallet, J.L. 2015. Genomewide association analysis for average birth interval and stillbirth in swine. Journal of Animal Science. 93(2):529-540.
Wells, J., Berry, E.D., Kalchayanand, N., Rempel, L.A., Kim, M., Oliver, W.T. 2015. Effect of lysozyme or antibiotics on fecal zoonotic pathogens in nursery pigs. Journal of Applied Microbiology. 118:1489-1497.
Buttrey, E.K., Luebbe, M.K., McCollum III, F.T., Cole, N.A., MacDonald, J.C., Hales, K.E. 2015. Effects of glycerin concentration in steam-flaked corn-based diets with supplemental yellow grease on performance and carcass characteristics of finishing beef steers. Journal of Animal Science. 93(7):3698-3703.