The Subtropical Agricultural Research Station (STARS) is a federal facility with program jointly supported and administered by the U.S. Department of Agriculture, Agricultural Research Service and the University of Florida, Institute of Food and Agricultural Sciences (IFAS). The location headquarters is about 7 miles (11 kilometers) north of Brooksville, Florida on Chinsegut Hill, one of the highest points in peninsular Florida at 274 feet (84 m) above sea level. Coordinates of the Main Station are 28º 37' 00" north latitude and 82º 21' 30" west longitude. Monthly distribution of rainfall and average monthly temperatures are given in Figure 1. Average annual rainfall is 54.0 inches (1,372 mm) with an average year-round temperature of 71.4º F (21.9º C). One to several killing frosts usually occur during the winter months (November - March).
The Station is composed of three major areas of land and one small acreage. The four units total about 3,850 acres (1,560 hectares) of which about 3,200 acres (1,295 hectares) are in permanent pasture including some small forage research plots. Between 300 and 400 acres (120 to 160 hectares) of the total 3,850 acres are wooded. Some of this wooded area provides shelter during inclement weather and during the calving season, and provides a source of shade. Most of the soils at the four units can be described as well-drained, loamy fine sands or fine sands (Entisols). The sand ridge and upland hardwood hammock ecological communities, of which STARS is a part, account for over 3.6 million acres (1.5 million hectares) in Florida. Combined, these ecological communities represent the largest land area in Florida after the flatwoods (Spodisols). Forage production potential of the soils at STARS is generally low to medium; the main limitation being droughtiness. Cattle production at STARS is forage based with bahiagrass (Paspalum notatum) currently the predominant forage species used at the station. Approximately 600 acres (240 hectares) are rhizoma perennial peanut (Arachis glabrata), a tropical legume with forage quality similar to alfalfa (Medicago sativa). Rhizoma peanut acreage is used for grazing experiments and to produce hay for winter feeding of the cow herds. The seasonal growth pattern of tropical plant species at STARS generally results in forage availability limiting animal production in the winter (December - February) and spring (March - May), while forage quality limits animal performance in the late summer and fall (August - November). Excess summer forage growth is stored as hay and constitutes the main winter feed for the cow herds. Hay yields average about 2 and 3 tons/acre (4 and 6 metric tons/hectare) from bahiagrass and rhizoma peanut, respectively. Forage quality of the hays, depending on time of harvest, range between 5 to 8% crude protein and 35 to 45% digestibility for bahiagrass and 10 to 15% crude protein and 50 to 60% digestibility for rhizoma perennial peanut.
Headquarters (Main Station) Unit. This unit is composed of about 1,000 acres, (400 hectares) most of which is in permanent pasture that is used for grazing and/or hay production (Figure 2). Soils at this unit are the most productive of the research station. Pastures are predominantly bahiagrass but there also are five acres (2 hectares) of leucaena (Leucaena leucocephala K8), a tropical, arboreal legume, and 105 acres (42 hectares) of rhizoma perennial peanut and mixed rhizoma perennial peanut - grass pastures. There are a total of 32 separate pastures at this unit.
Land Use Unit. The Land Use Unit is located a few miles north of the Main Station, east of U.S. Highway 41 (Figure 3). This unit is composed of about 700 acres (283 hectares), mostly in permanent bahiagrass pasture. There is one 12-acre (5-hectare) pasture of `Florigraze' rhizoma perennial peanut. Forage production potential of approximately 2/3 of this area is limited by periodic droughts. The remaining 1/3 is composed of soils with subsurface clay layers that minimize drought stress, but usually result in limited access to these pastures in the summer after heavy rainfall.
Turnley Unit. The Turnley Unit is located just west of Nobleton, Florida on County Road 476, about 5 miles (8 kilometers) from the Main Station (Figure 4). Most of the soils at this unit are excessively well-drained fine sands; forage production potential at this site is the lowest of the three main units. This unit has a total of about 2,150 acres (870 hectares) divided into 47 pastures. Twelve of these pastures, a total of 470 acres (190 hectares), are primarily composed of `Florigraze' rhizoma perennial peanut. The remainder of the pastures are primarily bahiagrass except for a 40-acre (16-hectare) location devoted to small plot forage research trials.
Other. Another 120 acres (49 hectares), half of which are wooded and the remainder in bahiagrass pasture with some aeschenomeme (Aeschenomeme americana) is located a few miles south of the Main Station (Figure 5) and is used for grazing as needed. A high water table during the summer months restricts use of this area to grazing only.
Main Station. Located at the Main Station are an office building, a laboratory building, a historical office building used for meetings and storage, and five buildings used for maintenance and storage. A barn with individual hand-feeding facilities for 24 animals, large forage dryer, feed grinding room, small wet laboratory, and hay and equipment storage is located near the HQ building. A small covered grandstand near the animal working facility is used for field days and educational purposes. A 16-pen feedlot with a total capacity of about 240 cattle, 15 head per pen is available. A small feed mixing and storage building also are located at the Main Station. There are two residences and one temporary quarters that can accommodate two graduate students or visiting scientists.
Land Use Unit. Located at this unit is a cattle handling area with working pens, hydraulic squeeze chute and electronic scale. Two small residences are available for visiting scientists and/or graduate students.
Turnley Unit. Facilities at this unit include cattle working pens, hydraulic squeeze chute and electronic scale, a maintenance building, and four hay storage sheds. There is one residence at this unit.
Currently, there are about 600 head of brood cows and heifers associated with various research projects at STARS. About 30 herd bulls are kept and, depending on the time of year, there may be 400 to 450 calves, and up to 400 yearling cattle. Some years, cattle are purchased for grazing and/or feeding experiments that can increase the total cattle inventory to 1,500 head. Essentially all of the breeding females 3-yrs and older are in a 3-breed diallel crossbreeding study using Brahman, Angus and Romosinuano. The origin of the three herds in use is described below.
Brahman. There are currently 200 head of breeding age purebred female Brahman cattle including a small number of miniature Brahman cattle that are the result of an autosomal recessive gene in the Brahman. Twenty cows and two bulls were purchased in 1949 from J. D. Hudgins Ranch, Hungerford, Texas. The present cowherd is predominantly of Manso breeding. Several bulls from prominent Brahman breeders have been used, mainly from W. H. Stuart Ranch, Bartow, Florida; A. Duda and Sons, Cocoa, Florida; U.S. Sugar Corporation, Clewiston, Florida; Heart Bar Ranch, Kissimmee, Florida; G. A. Tucker and Sons, Rockledge, Florida; Louisiana State University, Baton Rouge, Louisiana; OB Ranch, Wharton, Texas; Wyatt Flowers, Lithia, Florida; Tice Ranch, Bartow, Florida; and Texas A&M Agricultural Experiment Station, Overton, Texas.
Angus. There currently are100 head of Angus cows. Foundation cows were purchased in the fall of 1953 from the Everglades Experiment Station, Belle Glade, Florida. From 1954 to 1967, other purchases were made from the University of Florida at Gainesville, the North Florida Experiment Station at Quincy, the Front Royal Experiment Station at Front Royal, Virginia and from feeder calf sales in Virginia. The first bull used in 1954 was UF Postlemere 301. From 1955 to 1980, with one exception, only Wye Plantation bulls or sons of Wye bulls born at Brooksville were used. Bulls used from 1955 to 1969 were Barnos of Wye, Elector of Shempston, Fowler of Wye, Clayton of Wye, Montague of Wye and Fitzhugh of Wye. In 1967, the herd was expanded and 90 heifers were purchased from Tetley Farms in Staunton, Virginia. From 1970 to 1980, and artificial insemination program was used and included semen from Finlay of Wye, Lortez of Wye, Cornell of Wye, Filibuster of Wye, Favour of Wye, Lonestar of Wye, Linebacker of Wye, and Lucan of Wye. Between 1981 and 1988 two lines were selected for predicted high mature weight, Line A, or predicted high rate of maturing, Line K. During the 1989 and 1990 breeding seasons, several Wye Plantation sires were used in addition to Line A and Line K bulls from Brooksville. The herd was reduced to 50 females in 1996 and has been rebuilt using bulls produced from within the herd.
Romosinuano. There are currently 180 Romosinuano cows and two-yr-old heifers. All of these Romosinuano are either imported embryos or derived from our natural matings of imported embryos. A group of cows originated from embryos collected in 1991 from an upgraded Romosinuano cowherd at CATIE (Centro Agronomico Tropical de Investigacion y Enseñanza, Turrialba, Costa Rica), and are not pure Colombian Romosinuano. In 1997, 67 Romosinuano embryo transfer calves (34 heifers and 33 bulls) were born as a result of an importation of embryos from Venezuela that represent a broad sample of germplasm typical of the breed's Colombian origin. All females and the original bulls have been retained. Only pure Romosinuano bulls from Venesuela have been used. Older cows from Catie line will be phased out as the herd grows.
Angus-Brahman-Romosinuano Crossbred. A diallel crossbreeding project has been in progress since the 2002 calving season. Heifers from the project are being retained for evaluation of maternal effects. Nine possible breeds and crosses were generated each year over four years. The heifers are being exposed from weaning to low-birthweight Sanga bulls (heat tolerant types from Africa), either Mashona or Tuli. Long term productivity as cows will be evaluated for each breed and cross.
Hereford. The Hereford cowherd was dispersed in 1992. Semen (1,786 units) and embryos (112) collected from Line 4 Herefords (derived from Line 1 Herefords from Miles City, Montana shipped to Brooksville in 1962) were cryopreserved and stored.
Senepol. The Senepol cowherd was dispersed in 1998. Semen from 14 bulls produced at STARS (3,500 units) and from other U.S. sources (102 units) has been preserved. Embryos from approximately 38 Senepol cows (derived from an importation of 44 heifers and 4 bulls from St. Croix in 1982) have also been preserved.
Institutional Animal Care and Use Committee. On a twice annual basis, an Animal Care and Use Committee meets to review common production practices and experiments performed at STARS. Also at this time, animal handling facilities and general animal condition and environment are inspected. Throughout the year, participants of this committee review protocols of all animal research experiments prior to their initiation. The six-member committee includes a large-animal veterinarian, a scientist from the Brooksville staff, two non-scientists from the community, a non-scientist from Brooksville staff, and is chaired by the Superintendent of STARS (an animal scientist).
Herd Health Program. The herd health program at STARS is coordinated with the University of Florida, College of Veterinary Medicine, Large Animal and Clinical Sciences Department. The cattle herd has been certified Brucellosis free since 1958. At branding (May) and at weaning (September), calves receive a 7-way clostridial plus Haemophilus somnus vaccination and a 4-way respiratory plus Pastuerella vaccination. Heifers receive a Brucella calfhood vaccination. On an annual basis, prior to breeding (March), replacement heifers and mature cows are tested for brucellosis and are administered a 5-way Vibriolepto vaccination. Herd sires are also given a 5-way Vibriolepto vaccination at this time. A 5-way Vibriolepto booster is administered to heifers and young herd sires about 30 days later. Yearling and mature cattle periodically are sprayed during the summer for fly control and treated for lice as needed. No internal parasite control program is used in mature cattle.
The calving season extends from January through March. At birth, all calves are weighed, tattooed, dehorned (hot iron) if necessary, and ear tagged. Calves are weaned in September. Weaned calves are separated by sex and fed a weaning diet for a few weeks.
Breeding Program. Herd sires are fertility tested (breeding soundness examination) prior to the start of the breeding season. Most of the herd sires are two or three years of age. Breeding is generally performed by natural service, however, artificial insemination has been used at times. The breeding season begins in mid-March and extends 90 days. Forty-five to 60 days following the end of the breeding season all females are rectally palpated for pregnancy determination. Some embryo transfer has been used. Heifers from the diallel research project are exposed to low birthweight bulls at weaning to determine age at puberty. Steer calves are shipped to Oklahoma for wheat pasture and feedlot finishing where carcass traits can be determined.
Herd Data Base Management. Routine herd data and some research data are stored in a computer data base (COWBASE Production Testing Program, developed by the Animal Science Department, University of Florida and sponsored by the Florida Beef Cattle Improvement Association). Herd data management is based on cow-calf records and herd inventory records. A calf file is generated every year at the end of the calving season and includes calf identification, sex, breed, dam and sire identification, birth date, and birth weight.
A fully automated FAWNS (Florida Agricultural Weather Network Station) station was established at the Turnley unit in 1999. The measurements are reported to the National Oceanic and Atmospheric Administration (NOAA). Rainfall is measured daily at the main station with an automatic rain gauge (rotating drum type) and reported to the South West Florida Water Management District (SWFMD). A hygrothermograph is used to record humidity.
Feeding Program. Cattle are grazed predominantly in bahiagrass pastures with some strategic use of grass-legume mixed sward pastures. About 800 tons (725 metric tons) of grass (bahiagrass and bermudagrass) and legume (perennial peanut) hay are harvested for use in winter feeding. Hay is offered free choice to all cattle from first frost (about November 15) through about April 1 when spring grass becomes available. Mature cows are supplemented with fortified 4 lb/head/day (1.8 kg/head/day) molasses (16% crude protein equivalent) from weaning to spring grass availability, usually about April 1. Yearling heifers and two-year old heifers with calves also receive 5 lb/d (2.25 kg/d) soybean hulls mixed with the molasses. Bulls are fed a custom-mixed supplement (80% corn, 15% SBM [49.9% crude protein] premix containing 150 mg monensin/lb, 30,000 USP units Vitamin A/lb and 50 USP units Vitamin E/lb, and 5% molasses) three times each week at the rate of 5 lb/head/day (2.3 kg/head/day) for heifers and 10 lb/head/day (4.5 kg/head/day) for bulls. Two-year-old bulls and older herd sires are supplemented three times per week in the winter with 10 lb/head/day of the custom mix described for yearling heifers and bulls.