Previous research has shown that rangeland forage production can be increased through fertilization. A study was conducted to determine if fertilization of various Utah range sites was economically feasible. Six range sites were selected for analysis. The addition of nitrogen increased forage production on three sites. Phosphorus had no effect in increasing production. Production functions of the form, Y = a + bN - cN2 , where Y is pounds of forage per acre and N is pounds of nitrogen per acre, were estimated for both fall and spring applications. Using current prices of Y and N the optimum rates of fertilization for maximum profit were determined. By comparing the profit per acre for fall and spring applications the most effective season of application was determined. On an irrigated tall wheatgrass (Agropyron elongatum) pasture the fall application was most profitable and the optimum rate of N was 215 lbs. / ac (assuming PN = $ .1207/lb. and PY = $ . 0073/lb.). On an intermediate wheatgrass (Agropyron intermedium) foothill site, fall was the most profitable season of application and 127 lbs. / ac of N was the optimum rate. On a crested wheatgrass (Agropyron cristatum) site (average precipitation of 11 to 12 inches) only the spring application was analyzed and the most profitable rate of application was 7 lbs. N / ac. The optimum rates of N were determined for various prices of nitrogen and forage in a sensitivity analysis.

This study examined the food interactions between Utah prairie dogs (Cynomys parvidens, Allen) and cattle (Bos taurus), During 1974 and 1975, three prairie dog colonies near Panguitch, Utah, were studied intensely: "Oldfield" was chosen to represent colonies near fields of alfalfa (Medicago sativa); "Lowercrested" was chosen to represent colonies below 2,200 meters above sea level (a. s. 1.) which were not near alfalfa, and "Uppercrested" was chosen to represent colonies above 2,200 meters a.s.l. which have been planted with crested wheatgrass. Visual observations were made of Utah prairie dogs to determine their diets. Livetrapping of prairie dogs provided data for estimates of population sizes and animal weights, which were used to calculate forage requirements. Cattle diets and forage intake per individual were derived from the literature. Much more forage was available to prairie dogs than to cattle. About 80 percent of the forb phytomass ingested by prairie dogs at Uppercrested never would have become available to cattle. Prairie dogs foraged more selectively than cattle are capable of doing. Neither animal showed a general dietary preference toward either grasses or forbs: each plant life form contained bath preferred and avoided species. Bath animals had a low preference for shrubs. Oldfield's area tripled between 1971 and 1974, but Uppercrested did not expand. Between 1 June, 1974, and 1 June, 1975, Oldfield's population increased from about 42 to 70 adult prairie dogs, and the colony's area increased proportionately; however, Uppercrested's population appeared to decline from approximately 22 to 19 adults. The dissimilar expansion rates, at least between 1974 and 1975, probably were due to differences in behavior, forage availability, nutrition, and predation. Oldfield's prairie dogs gained weight much faster than did Uppercrested's animals. Thus, the average number of active Utah prairie dogs ingesting as much forage as a cow and calf from March through October (prairie dogs fed little during other months) was 410 at Oldfield, compared to 500 at Uppercrested. Numbers concerning total utilization may be even higher: prairie dogs waste little vegetation, but cattle probably trample much. On the other hand, prairie dogs clip closer to the ground and earlier in the growth season than do cattle; consequently, prairie dogs may cause a greater reduction in primary production for the same amount of forage intake. Population densities of prairie dogs in late June, one month after the young first emerged, were 35/ha at Oldfield, 16/ha at Lowercrested, and less than 2.3/ha at Uppercrested. Prairie dogs used over 70 percent of the primary production of perennial herbage at Oldfield and about 10 percent of it at Lowercrested. Uppercrested's prairie dogs used approximately 3 percent of the primary production of crested wheatgrass, a preferred forage. Within any one year, cattle probably rarely reduce population s of Utah prairie dogs, and possibly may increase populations in colonies with high primary production. Prairie dogs apparently have reduced the primary production of perennial herbage at bath Oldfield and Lowercrested. Vegetational canopy coverage was greater on mounds than off mounds in the low use portion of Uppercrested. Heavy grazing by livestock in the past probably has eliminated much Utah prairie dog habitat: swales have been destroyed and early spring forage has been reduced.

A stratified sample of 420 market hogs representing the seven 10- pound incremental carcass weight classes from 140 lbs. to 210 lbs. , and the nine last rib back fat classes from less than .8 inches to 1.5 inches, or greater, within each weight class were analyzed to determine carcass value and yield of wholesale cuts. Simple correlation coefficients were calculated between each of the carcass measurements. The carcass yield data were manipulated by multiple regression procedures to achieve a series of equations for predicting the weights of the primal cuts. The benefits of being able to predict the weights of the primal cuts were discussed. A procedure for developing a premium/discount matrix was explained . The fo rmulae for developing the matrix were explained. The necessary assumptions were also explored. A procedure for evaluating a premium/discount matrix was developed. The impact of an industry-wide carcass merit program was discussed.

An increasing interest in fecal analysis as a method of determining diets of herbivores prompted research to determine if this method could be used successfully to determine diets of pronghorn antelope found in Utah's cold desert rangelands. In addition to fecal analysis, quantitative estimates of pronghorn diets were derived from rumen analysis and feeding site observations. Rumen samples were analyzed by three different methods : (1) microscopic, (2) gravimetric, and (3) point frame. In addition to field experiments, samples from a feeding trial with a diet of known composition were used to determine whether or not differential digestion of plant epidermis occurs. Fourteen male pronghorn antelope were collected between July, 1970 and June 4, 1971 on the Desert Experimental Range near Milford, Utah. A fecal sample was taken from the intestine of each. In addition, fecal samples and estimates of vegetative composition were collected at 14 sites. These, plus eight rumen samples collected from hunter kills during August 1970, were used to compare methods of rurren analysis and fecal analysis with the other conventional techniques used in this study. Of the methods used, the microscopic technique, as described in this study, provided the most accurate and efficient method of analyzing pronghorn rumen samples. fecal analysis results compared favorably to the other methods used. The known diet study indicated that differential digestion of epidermal fragments may occur under certain conditions.

A feeding trial was conducted comparing four finishing diets, typically fed in this area, two hormone implants zeranol (Ralgro) and estradiol 17-beta (compudose), and a feed additive. thirty-two Hereford steers were fed in individual pens to maintain accurate intake records. The four diets compared were: 1) a whole corn diet with a small amount of corn silage as roughage; 2) a high energy ground barley diet using corn silage and chopped alfalfa as roughage; 3) a total diet consisting of rolled barley, beet pulp, and ground alfalfa hay; and 4) a high energy rolled barley diet using corn silage and chopped alfalfa hay as roughage. All finishing diets were supplemented with a protein, vitamin, and mineral supplement containing monensin. The cattle were fed in two phases--a growing and finishing phase. The diet comparisons were conducted only during the finishing phase. The implant and additive comparisons were made over both phases. Diet had little effect on feed lot performance. Rate of gain and feed efficiency were not significantly affected. Voluntary intake of net energy for gain was significantly affected (p<.01) by diet. Cattle fed diet #1 consumed significantly more net energy for gain than cattle on diets #2, 3, and 4. The effect of diet was also significant for internal fat percent and marbling score (p<.05). Cattle fed diet #2 had the highest internal fat percent (3.06%) followed by those on diets #3 (2.6%), diet #1 (2.3%), and diet #4 (2.1%). Marbling scores were similar with cattle on diet #2 showing significantly higher (p%lt;.05) marbling scores than the other three groups. No other carcass characteristics were affected. The difference between the implants used was very small. None of the feedlot performance traits were affected. The feed additive Trigrr II produced significantly more (p<.05) efficient gains during the growing period. This efficiency was apparent during the finishing period. Average daily gains were significantly higher for Trigrr II fed cattle (p<.05). During the combined period, average daily gain and feed efficiency were both superior for Trigrr II fed cattle (p<.05). Ribeye and hot carcass weights were significantly affected also (p.01). Cattle fed Trigrr II were superior in this case. Cattle implanted with zeranol fed Trigrr II consumed significantly greater amounts of net energy for gain and had heavier hot carcass weights than estradiol 17-beta implanted cattle or zeranol x control cattle.

An experiment was designed to study the effects of forage availability, season and intensity of grazing, and distribution and behavior of sheep on their forage preferences. Three grazing periods of 15 days each were used to study the effect of season. Each grazing period included a heavy and a moderate stocking intensity. Pastures were divided by a grid into 30.48 m x 30.48 m compartments. Each compartment was sampled for botanical composition of available herbage prior to and after grazing. Esophageally fistulated sheep were allowed to graze freely and positions of individual sheep with respect t o compartments were recorded at 5-minute intervals during the daily forage sample collection period. Immediately following collection of fistula samples, daily measurements were taken on leaf area index and height for all plant species. Estimates of aerbage yield and forage utilization were derived from heightleaf area measurements by regressions. Botanical composition of the diet was determined through microscopic analysis of plant cuticle fragments on dried, ground esophageal samples. Analysis of the dietary data indicated that season had no effect on the botanical composition of diets of sheep. However, grazing intensity significantly (P < 0. 20) affected diets of sheep. Significant differences (P < 0 . 01) were also found in proportion of plant species that comprised the diet at any particular time. Individual sheep were significantly (P < 0.01) different in their forage preferences . There were no significant changes in botanical composition of the compartments due to grazing. However. bare ground increased significantly (P < 0.10) more under heavy stocking than under moderate stocking. Herbage yield was found to be highly correlated with leaf area index and height (r2 = 0.85) in the ungrazed control pasture. Forage yield in the grazed pastures was a l so correl ated with leaf area index and height (r2 = 0.79) . Utilization was estimated as the difference between the two parameters . Sheep were observed to graze more heavily around the periphery of shrubs than in the interspaces. The heavily grazed areas around shrubs were found to be significantly larger in heavily stocked pastures (P < 0.10) . Observations of grazing behavior showed that sheep tended to orient themselves toward conspicuous objects . In so doing, they grazed a strip leading from one conspicuous object to another (ex. shrubs) . In an experiment designed to determine the role of such conspicuous objects in animal distribution and feeding behavior, sheep distribution, in relation to randomly-placed cardboard boxes. was found to be non-random and significantly (P < 0.05) related to the position of the boxes. It was also found that sheep grazed the herbaceous species to a certain height below which the plants became inaccessible to grazing. Micro-associations of plant species greatly influenced preferences. Sagebrush (Artemisia tridentata) plants exerted a negative effect on use of adjacent bitterbrush (Purshia tridentata) plants. This negative effect was determined by the distance between the two shrubs. This "critical distance" was found to be 56.1 ± 23.7 cm and was not affected either by season or stocking intensity . An equation was developed by multiple regression to predict diets of grazing sheep. This equation explained 52% of the variation in botanical composition of the diet. Visual orientation of individual sheep, while grazing, modified to a large extent their forage preferences.

The addition of the Streptococcus lactis culture in the pasteurized milk was studied, in an attempt to find the effects of the culture in prolonging shelf life of the milk. Various concentrations of the culture were tried to find the optimum concentration that would give favorable effect on keeping quality of the milk. It was found that the addition of Streptococcus lactis culture at the rate of 0.0001 percent has shown promising effects in prolonging shelf life of the milk at the storage temperature of 40 F. In addition to the above study, effects of added acid in the pasteurized milk, were studied. The adjustment of pH with the addition of the citric acid used in these studies, had no effect in extending the keeping quality of the pasteurized market milk. The acid treatment of the milk showed spoilage earlier than the control samples of the milk. Two temperatures, 40 F and 50 F were studied to find suitable temperature for storage of the milk. It was observed that the 50 F is not a desirable temperature for storage of pasteurized milk. A 40 F temperature was found better for storage of the milk. Bacteriological studies done simultaneously, on pasteurized milk stored at 40 F, showed that the coliform organisms did not multiply at that temperature. The initial bacterial counts on psycrophilic organisms were negative; but after seven days their presence was in large number. The number of organisms as determined by the Standard Plate Count, was not a reliable indicator of the keeping quality during storage temperature of 40 F.

This paper entails the economic and biological interpretation of the response of rangeland grasses to nitrogen fertilization. Six sites throughout Utah received graduated rates of fertilizer. The coefficients of the production function Y = a + bN - cN2 were identified. An initial production and a carry-over response were identified on sites recei ving greater than ten inches of annual precipitation. Optimum fertilization rates may be identified by equating the marginal physical product to the ratio of the price of nitrogen to the price of the forage. Forage response to nitrogen is reflected strongly in the early growth response in which fertilizer rates of 15 to 120 pounds of nitrogen per acre produce adequate forage for grazing 4 to 18 days prior to unfertilized range.

A reliable technique for obtaining late prophase, prometaphase and greater numbers of metaphase chromosomes is presented. The increased number of mitoses and high resolution chromosomes were obtained using a modification of the typical three-day blood c ulture technique in which the cell cycle was temporarily blocked at the G1 -s border with methotrexate. A high resolution G-band idiogram is presented using a system similar to the standardization of human chromosomes. The use of this technique and system of nomenclature will facilitate routine analyses of horse chromosomes and provide a basis for the identification and recording of chromosome aberrations in this species. C-bands and NORs of the domestic horse are also described. C-bands, NORs and high resolution G-bands of control horses were compared with those of horses affected with Hereditary Multiple Exostosis. No differences were found on NORs, C- and G-bands between control and exostosis horses.

The conflicting problem involving the herds of mule deer (Odocoileus hemionus) are of major interest throughout Utah. Individuals who are affected the most are sportsman, ranchers, fruit growers, sanitation engineers, home owners, federal administrators, and big game managers. Mainly, the problem arise as a result of insufficient forage, especially on the winter range. Here, factors such as increased deer numbers, decreased range productivity, severe winters, and expanded agricultural activity make more acute the problem of a naturally critical season.