Freetly, Harvey C.
Supervisory Research Animal Scientist
U.S. Meat Animal Research Center
Agricultural Research Service
U.S. Department of Agriculture
P.O. Box 166
Clay Center, NE 68933
USMARC Vicinity Map
Research in the nutrition unit is focused on genetic and environmental factors that lead to variation in efficiency in beef and sheep production. This research addresses measures of efficiency at different phases of the production system to identify those factors that have additive merit and antagonistic relationships across the different phases of production. The initial objective is to develop facilities and methodologies to efficiently collect economically and biologically important phenotypic data relevant to efficiency. After developing capabilities to measure the phenotypes, the contribution of genetics and environment/management to variation in efficiency of production will be determined. Genetic variation will be evaluated using both quantitative genetics and QTL discovery. Information gained from both the genetic and environmental studies will be used to parameterize simulation models that provide decision support software to allow producers to simulate potential outcomes to optimize production efficiency when different combinations of animal genetics and management strategies are used.
USMARC is situated on 35,000 acres of grazing and farm land in Central Nebraska and maintains about 6,800 breeding cows (20 breeds represented), 400 sows, and 3,000 breeding ewes to provide animals for experiments, genetic studies, QTL discovery and genetic marker identification. The center also maintains an abattoir equipped with pre-evisceration and carcass washers and a spray chill unit for the efficient slaughter and processing of cattle, sheep and swine.
The nutrition unit is housed on the second floor of Building 1 and scientists in the unit have access to a full complement of laboratory equipment for sample analysis. Common laboratories are equipped with gas chromatographs, mass spectrometers, refrigerated centrifuges and ultracentrifuges, high pressure liquid chromatographs, clinical analyzers, and isotope counters for the analysis of biological samples. A common proximal analysis laboratory is used for the analysis of feed samples, animal products, and manure. Animal housing facilities are available for conducting metabolism studies in sheep, beef, and swine and include the capability to conduct balance trials with indirect calorimetry. Facilities are also available for experimentation with mice, rat and rabbits.
Scientists in the unit have access to an on-site automated DNA sequencing facility, a Sequenom MALDI-TOF mass spectrometry genotyping system and substantial computing capacity and software tools. Availability of livestock populations has allowed the development of genomic comprehensive linkage maps, BAC, YAC and cosmid-based genomic libraries for cattle and swine, highly normalized expression libraries derived from a number of bovine and procine tissues and a database of sequences from over 100,000 clones, each from cattle and swine expression libraries.
Data handling and computational resources include a DEC Alpha 4100 and dedicated workstations. State-of-the-art software for sequence editing, assembly and annotation is available on each of these platforms. The center maintains a secure network and database containing animal, infectious agent and sequencing data. For DNA community profiling, a Dcode system is available.
A 6,000 head feedlot for cattle and smaller group pens for sheep and cattle are available for conducting extensive nutrition studies. Current individual cattle feeding facilities include 432 Callan head gates distributed within 52 pens that are housed in four barns. Each gate is programmed to allow access to a single animal, hence there are also 432 feeders. Individual feed intake is obtained by weighing the feed that is put in each feeder and the orts that remain.
A state-of-the-art feeding system has been purchased and is scheduled for installation during late January in a recently built barn that partially covers six pens sized to hold 50 growing-finishing cattle or 25 to 30 mature cows each. The system will enable us to monitor and influence the individual feed intake behavior of cattle. The system consists of a feeding gate that identifies the animal, gives or denies it access to the feed trough and records the visiting time. After the visit, the duration of the visit and feed consumed during each visit is recorded. This enables measurement of how much an animal has eaten from a certain feed type per visit. Each animal can be given access to one or up to four different feeds. Both ad libitum and restricted feeding are possible. The system also provides the capability to measure amount and pattern of water intake and provides the ability to “flag” animals that deviate from parameters for feed or water intake. Windows based software is used to run the system and data are stored as ASCII files that can be uploaded for further processing.
The above animal facilities allow scientists in the unit to conduct experiments with large and small animals. These experimental are useful in developing biological life-cycle system models that are applied in decision support software. Laboratory and computing facilities in combination with on site experimental and production data facilitate QTL discovery for efficient phenotypes, and ultimately marker identification for these phenotypes.