Browsing by Subject "Cattle"
Now showing 1 - 20 of 59
Results Per Page
Sort Options
Item A comparison of semen thawing for artificial insemination in cattle.(2011-05-26T18:13:05Z) Kaczyk, Brittni L.; Kaczyk, Brittni Lanay; Serrano, Gabriela I.; May, Brain J.; Scott, Cody B.; Salisbury, Michael W.; Angelo State University. Department of Agriculture.Beef cows (n=23) were used to compared conception rates of two different thawing methods used for artificial insemination (AI). Cows were divided into the treatment or control group based on time of estrus. In the treatment, frozen semen was placed directly into the AI gun and inserted into the female for deposition after a minimum of 30 seconds. The control females experienced the typical thawing process of semen straws placed in a water bath for a minimum of 30 seconds, then loaded into the AI gun and deposited into the uterus of the female. Conception rates were similar between semen thawing methods (P > 0.51). Additionally, the study analyzed semen motility using the two different thaw methods and found no difference (P = 1.0). In conclusion, thawing semen directly in the reproductive tract of the female provides the same conception rates as traditional thaw methods.Item A study of the breeding efficiency of bulls in the Texas Tech bull stud(Texas Tech University, 1950-12) Baumhardt, Roland E.Not availableItem Addition of an enzyme combination of gibbrellic acid to sorghum grain for feedlot cattle(Texas Tech University, 1988-05) Karr, Kendall J.NOT AVAILABLEItem An economic analysis of cattle weight gain response to nitrogen fertilization and irrigation on WW-B. Dahl bluestem(2005-12) Dudensing, Jeffrey D'Wayne; Johnson, Jeff; Johnson, Phillip N.; Lansford, Vernon D.; Villalobos, CarlosThe objective of this research was to estimate total stocker steer gains ha-1 at various levels of nitrogen fertilization and irrigation application on WW-B. Dahl Old World bluestem. In order to do this, forage mass and quality responses to nitrogen (N) and irrigation (I) had to be determined. The data for this study were obtained from two independent studies conducted from 2001 to 2003 at Texas Tech University. Stata statistical software was used to obtain coefficients for the effects of accumulated growing degree days (AGDD), N, I, precipitation, and maturity on forage mass and quality. Quality assessments were based on acid detergent fiber (ADF), neutral detergent fiber (NDF), and crude protein (CP). Panel data with fixed effects was the most appropriate statistical model. Statistical tests confirmed that the model was corrected specified. From the forage mass and quality values, the National Research Council’s Nutrient Requirements of Beef Cattle 2002 equations were used to estimate total stocker steer gain ha-1. In estimating total stocker steer gains, a monthly utilization of 70% of forage mass was assumed. Estimated average daily gains were validated with previous research. The results agreed with the findings of Mitchell et al. that GDD could be used to estimate forage mass and quality. However, N, I, precipitation and maturity can be incorporated into Mitchell’s model to increase the understanding of forage mass and quality. By using these regressions and incorporating them into the NRC equations, the response to variable rates of N and I was evident in stocker steer gains. Three initial steer weights (181 kg, 227 kg, and 272 kg) were used to capture the effect on gains. Results indicated that individual steer gains were higher with low irrigation and high nitrogen fertilization levels. Total cattle gains were maximized with high irrigation and high nitrogen levels.Item An economic analysis of cattle weight gain response to nitrogen fertilization and irrigation on WW-B. Dahl bluestem(Texas Tech University, 2005-12) Dudensing, Jeffrey D'Wayne; Johnson, Jeff; Johnson, Phillip N.; Lansford, Vernon D.; Villalobos, CarlosThe objective of this research was to estimate total stocker steer gains ha-1 at various levels of nitrogen fertilization and irrigation application on WW-B. Dahl Old World bluestem. In order to do this, forage mass and quality responses to nitrogen (N) and irrigation (I) had to be determined. The data for this study were obtained from two independent studies conducted from 2001 to 2003 at Texas Tech University. Stata statistical software was used to obtain coefficients for the effects of accumulated growing degree days (AGDD), N, I, precipitation, and maturity on forage mass and quality. Quality assessments were based on acid detergent fiber (ADF), neutral detergent fiber (NDF), and crude protein (CP). Panel data with fixed effects was the most appropriate statistical model. Statistical tests confirmed that the model was corrected specified. From the forage mass and quality values, the National Research Council’s Nutrient Requirements of Beef Cattle 2002 equations were used to estimate total stocker steer gain ha-1. In estimating total stocker steer gains, a monthly utilization of 70% of forage mass was assumed. Estimated average daily gains were validated with previous research. The results agreed with the findings of Mitchell et al. that GDD could be used to estimate forage mass and quality. However, N, I, precipitation and maturity can be incorporated into Mitchell’s model to increase the understanding of forage mass and quality. By using these regressions and incorporating them into the NRC equations, the response to variable rates of N and I was evident in stocker steer gains. Three initial steer weights (181 kg, 227 kg, and 272 kg) were used to capture the effect on gains. Results indicated that individual steer gains were higher with low irrigation and high nitrogen fertilization levels. Total cattle gains were maximized with high irrigation and high nitrogen levels.Item An economic analysis of waste management for Texas cattle feedlots: an analysis of system alternatives and policy implications(Texas Tech University, 1994-08) Glover, Teresa P.Over 20 percent of the nation's fed cattle are finished each year in the Texas High Plains. Each animal that is fed produces approximately one dry ton of collectable manure. This equals about two dry tons of collectable manure per year per head of feedlot capacity. Given the amount of cropland in crop production on the High Plains, there is a potential demand for all manure produced. The general objective of this thesis was to determine efficient waste management strategies which would be environmentally benign while benefiting agricultural producers. Specific objectives were sought with respect to the physical aspects, cost of manure management, derivation of manure demand curves, and possible policy implications. Mathematical optimization models for two study areas in the Texas Panhandle were developed with the objective of maximization of net returns. The primary differences between the Northern Farm Area and the Transition Farm Area were the addition of cotton production in the Transition Farm Area as well as decreased farm size. Crop supply and input demand functions were determined using duality theory.Item An evaluation of the role of organic selenium in immune function in cattle.(Texas Tech University, 2008-05) Covey, Tanya L.; Galyean, Michael L.; Wester, David B.; Defoor, Paul J.; Albin, Robert C.Selenium (Se) plays a vital antioxidant role as a constituent of glutathione peroxidase (GSH-Px). Newly received feedlot cattle are exposed to multiple factors that can lead to oxidative stress, including viral infection. The objective of the research conducted for this dissertation was to evaluate the effects of different Se sources on immune function (Exp. 1) of calves challenged with infectious bovine rhinotracheitis virus (IBRV) and on health and performance in a field study (Exp. 2). In Exp. 1, 24 Holstein steers (BW = 148.2 ± 2.79 kg) were assigned randomly to treatments, including: 1) Control = no supplemental Se; 2) Sel-Plex = 1 mg/(steer•d) of Se from Se yeast (Sel-Plex; Alltech Inc., Nicholasville, KY); or 3) Selenite = 5 mg/(steer•d) of Se from sodium selenite. The Se sources were fed for 28 d before steers were intranasally inoculated with IBRV (d 0) and continued through 21 d after the challenge. Treatments did not affect body weight (P > 0.05) or feed intake (P > 0.30) before or after the challenge. Whole blood Se concentrations were greater (P < 0.01) when Sel-Plex was fed than with the other two groups, but GSH-Px activity (P > 0.20) was not affected by treatment. Supplemental Se tended (P = 0.08) to increase IBRV titer values on d -14 but to decrease (P = 0.06) titers on d 21. Steers fed Sel-Plex tended (P = 0.08) to have lower rectal temperatures for 18 h before the challenge than steers fed selenite, but there were no other differences (P > 0.10) in rectal temperature. Serum interleukin-1b concentrations were lower overall (P = 0.02) and tumor necrosis factor-á concentrations 12 h after the challenge were greater (P = 0.04) in steers fed Sel-Plex than in those fed Selenite. In Exp. 2, crossbred newly received heifers (4 pens/treatment) were fed the same treatments as in Exp. 1, except that Selenite supplied 1 mg/(heifer•d). No differences (P > 0.10) among treatments were noted for performance or health during the 28-d study. Additional research is needed to clarify how providing Se in the form of Sel-Plex affects immune response to viral infections in cattle.Item And the ocean came up on land : perceptions of adaptive capacity of cattle ranching in Vermilion Parish, Louisiana(2013-05) Adams, Danica Claire; Dooling, Sarah; Moore, Steven A., 1945-Cattle ranching in Vermilion Parish is a social-techno-ecological system (STES) that is currently vulnerable due to changing social, technological and ecological conditions. In addressing ways to increase the adaptive capacity of cattle ranching in Vermilion Parish, I used a multiple, mixed method approach grounded in a critical constructivist framework. Constructivism is the idea that our relationship to facts is constructed by our social context. It is these perceptions that shape people’s actions. By looking at these perceptions through an emancipatory frame I was able to understand multiple interpretations of meaning, consciously address them, consider how they may have shaped our actions, and then alter those meanings and power relationships. In an effort to increase the adaptive capacity of cattle ranching in Vermilion Parish, my research focused on actions, why people perform those actions, and how to change them. This research connected the physical landscape of the marshes, the individual landscape of perception, and the conceptual landscape of resilience. If resilience is the ability of a system (cattle ranching in vermilion parish) to recover after a disturbance, adaptive capacity is when the actors within the system can influence that system’s resilience. I explored the history of cattle ranching in Vermilion Parish from three different, but overlapping perspectives – environmental, social, and technological. These perspectives compliment the information from interviews and 3CM sessions. These 15 interviews revealed the perception of 11 types of threats facing cattle ranching in Vermilion Parish. The body of literature surrounding resilience theory identifies traits of highly adaptive systems. The recommendations and suggestions outlined in Chapter 6 exist at the intersection of the actors’ perception of specific threats and the decidedly generalized traits of highly adaptive systems. These suggestions were geared towards increasing the adaptive capacity of cattle ranching in Vermilion Parish. Given these layered landscapes and their complexity, my recommendations were subject to feedback loops and long periods of integration. These recommendations contribute to the theoretical foundation detailed in Chapter 3 by identifying specific ways that the actors of this particular system may be able increase their own adaptive capacity.Item C.E.O. on the range : Murdo Mackenzie and the Matador Ranch in an age of reform, 1891-1911(Texas Tech University, 2004-08) Turner, Leland K.Not availableItem Cattle grazing and biosolids in West Texas(Texas Tech University, 2004-05) Avila, Jose-MiguelLime stabilized biosolids applications on rangelands were evaluated by cattle grazing in 2000 and 2001 on six, 16-ha pastures. Three pastures were treated with 20 dry ton per ha and 3 untreated pastures were used as a control. Average daily gain of steers grazed on test pastures for 120 days were evaluated through two grazing seasons. Forage samples were collected to determine forage availability and forage quality. At the end of each performance trial, animal tissues were collected from liver, muscle, kidney, and heart to evaluate trace elements. An additional four, 8-ha pastures were used to document animal behavior. Each of these four pastures was divided in half. Biosolids was applied in one half of the pasture at 20 dry ton/ha; the other half was untreated. Animal behavior was evaluated in 4-day consecutive periods, during 12 hours of direct observations at the beginning and end of each grazing season of the performance trial. Average daily gain was similar (P>0.05) between treated and untreated areas with 0.249 and 0.238 kg per animal and with 0.140 and 0.139 kg per ha in year 2000, as well as 0.435 and 0.377 kg per animal and 0.154 and 0.118 kg per ha in year 2001. Tissue samples from steers grazing on treated pastures were similar in trace elements (P>0.05) compared with those collected on untreated pastures. The steers spent 5 hours and 40 minutes per day grazing in 2000 with 57% of grazing time spent in the biosolids-treated area. In 2001, steers spent 6 hours and 53 minutes grazing with 56% of grazing time spent in the biosolids area. In conclusion, biosolids affect animal performance when conditions are favorable especially rainfall and temperature. However, steer grazing behavior showed preferences for grazing activities on the biosolids areas. Biosolids applications positively affect forage quality, especially crude protein.Item Characterization of young bulls in a cooperative seedstock program for marketing and mating decisions(Texas Tech University, 2002-05) Dean, Dustin TylerThere are two main sections that are targeted towards seedstock and commercial beef producers within this thesis. The first, entitled "Characterization of Young Bulls in a Cooperative Seedstock Program for Marketing and Mating Decisions," addresses the selection criteria used by commercial buyers at yearling bull sales and determines their effects on yearling Gelbvieh, Angus and Red Angus bull prices. The second, "Development of a Computer-based Sire Selection Program for Beef Producers and for undergraduate Beef Production Students," is a description of a current development of a new breeding tool related to sire selection. Although two separate entities, the two subjects are very similar. Development of the computer-based program began early in the Master's program and will continue to be modified until its completion, while the customer selection criteria analysis began towards the end of the Master's program. Both are examples of extended efforts that can be made by those within the seedstock industry to better meet the needs of the commercial customer. The two sections can be viewed as steps that a seedstock supplier can take in an effort to expand their customer base. Step one, analyzing the selection criteria of the customer, is an effort to identify and better understand the personal markets and production preferences that are associated with each producer. Once these markets and preferences are identified, step tw o, the computerbased sire recommendation program, could be viewed as the final step in an effort to adapt and provide a total service commitment to customers by reducing the risk associated with sire selection decisions.Item Conception rate differences in sexed vs. non-sexed semen(2011-06-21T22:18:13Z) Brooks, Kayla L.; Brooks, Kayla Lynn; Salisbury, Michael; Ammerman, Loren; Engdahl, Gil; May, Brian; Angelo State University. Department of Agriculture.The objective of this study was to determine if sexed semen has similar conception rates as non-sexed semen. Eighty-four Angus females from the Angelo State University’s Management, Instruction and Research Center were synchronized at the beginning of this study; however, only 54 showed signs of estrus and were artificially inseminated (10 Heifers and 44 multiparous cows). The 54 females were split randomly into three different treatment groups. Heifers and cows in treatment one were inseminated with Y-bearing sexed semen. Females in treatment two were inseminated with X-bearing sexed semen; while the last treatment was our control which received non-sexed semen. Results in heifers and cows were similar, and no differences were noted among the three treatment groups (P>0.5). Differences might be noted with a larger number of females. Date of parturition was estimated using ultrasound, and is a viable management tool because it is possible to predict, on average, within 9 days of parturition with a 36 day maximum and an exact prediction for the minimum.Item Correlations of first period and second period average daily gains of cattle fed all-concentrate rations(Texas Tech University, 1967-06) Cox, Donald BoydCattle feeders' profit margins have been declining rapidly, therefore ways of cutting costs are constantly being sought. One costly item to the feeder is slow gaining cattle. Their lower rate of daily gain means less profit is being made each day from the conversion of grain to beef. Too, the extra time required to obtain the desired finish on these animals costs the feeder in both extra interest on his investment and extra feed for maintenance. Evidence of a high positive correlation between the early short term gains and the later long term gains would enable the feeder to cull the slow gainers after the short period and replace them, hopefully, with faster gainers. The objective of this study was to determine if there is any significant correlation between the early short term gains and the later longer term gains of cattle fed high concentrate rations. Data analyzed in this study were collected from experiments conducted at Texas Tech Feedlot, Lubbock, Texas, and Texas Tech Research Farm, Amarillo, Texas, in which high concentrate rations were fed.Item Early pregnancy diagnosis and embryo/fetus mortality in cattle(Texas A&M University, 2006-04-12) Romano, Juan EduardoPregnancy diagnosis by transrectal ultrasonography (using a 5 MHZ linear probe) presented the maximum sensitivity and negative predictive values at day 26 and day 29 after estrus in heifers and cows, respectively. Palpation per rectum using the fetal membrane slip for pregnancy diagnosis did not increase embryo/fetus mortality when compared with a positive control group of non-palpated females. The use of a controlled randomized block design was a useful approach to study this problem. Blocking for category and number of embryos allowed us to remove these confounding factors. Factors that affected pregnancy loss during the first four months of pregnancy were: period of pregnancy, age of the animal, number of previous lactations and number of embryos. Pregnancy loss was higher during the embryonic than fetal periods. Spontaneous embryo/fetal mortality increased with the age of the animal and lactation number. The risk of spontaneous embryo/fetus mortality was higher in twin than in single pregnancies. Two types of embryo/fetus mortality were noted: Type I and Type II. Type I was characterized by presence of positive fetal membrane slip by palpation per rectum, signs of degeneration by transrectal ultrasonography and persistence of a functional corpus luteum. The uterus took approximately 3 weeks to be noted clean by transrectal ultrasonography and the animals showed estrus one month after the conceptus was diagnosed dead. Type II was characterized by absence of positive signs of pregnancy by palpation per rectum, absence of signs of degeneration by transrectal ultrasonography and absence of a functional corpus luteum. Pregnancy loss in nuclear transfer derived embryos was higher compared to in vivo derived embryos produced by artificial insemination. Pregnancy loss occurred mainly during the transition from the embryonic to the fetal period. Embryo/fetus mortality detected was Type I. Progesterone produced by the corpus luteum was noted at pregnancy levels for approximately two weeks after embryo/fetus death. Protein B, a hormonal placental marker, was maintained at pregnancy levels for approximately 3 weeks after embryo/fetus death. No differences in the levels of the two hormones were noted when comparing females with dead or live conceptuses.Item Economic and production efficiency aspects of variable energy density in the diets of identical twin calves(Texas Tech University, 1989-05) Robbins, Randall DarylDespite the large amount of research evaluating the effects of various levels of nutrition on cattle growth, feedlot performance and carcass development, conflicting opinions remain. O'Donovan (1984), in a review article, summarized these studies in an attempt to find a common denominator that would help explain the variable but he had little success. Obviously a major contributing factor to these diverse results would be extensive variation in experimental methodology. Cattle used in experimentation differ in biological type, age, sex, diet and previous environmental treatment. Investigations have been conducted restricting energy consumption so that animals lose weight, maintain their weight or gain weight (gains are limited below maximum gain potential). In addition, proportion of maximal weight gain by energy restricted animals varies considerably between studies. Type of restriction also is different. Cattle can be restricted by reducing total daily feed consumption, reducing dietary energy concentration through feed ingredient manipulation or combinations of both. Length of restriction periods also differs. Some researchers reported that cattle were maintained on low energy diets for the entire feeding period while others provided a period of high energy consumption or a refeeding period. Cattle subjected to these diverse growth limiting treatments then were compared to cattle consuming a common dietary treatmentcontinuously fed animals consuming high energy diets. Consequently, comparisons then were made with cattle at different or similar weights and various ages.Item Effect of inorganic and organically complexed trace minerals on growing cattle consuming drinking water with high levels of sulfate(Texas Tech University, 2004-05) Mikus, Jeffrey HeathTwo experiments were conducted to determine the effect of trace mineral source on sulfate metabolism in cattle, and a third trial explored the effect of sulfur source on thiamin disappearance in vitro. In the first experiment, crossbred heifers (335.54 kg) were supplemented with an organically complexed source of Cu, Zn, Mn, and Co; an inorganic source of Cu, Zn, Mn, and Co; or no added trace minerals. Heifers were assigned to one of two water treatments, no added sulfate (NS); (39,5 mg/kg sulfate) or high-sulfate (WS); (1,810 mg/kg sulfate). Average daily gain for heifers consuming NS water was higher (P = 0,04) than for those consuming WS water for the first 28d. Water source had no effect on gain for 29 to 56 (P = 0.07) or 0 to 56d (P = 0.77). Feed-to-gain was lower (P = 0,01) for NS heifers than for WS treatments for the first 28d. Water source had no effect on feed-to-gain for 29 to 56 (P = 0.06) or 0 to 56d (P = 0.44). Mineral source had no effect (P = 0.18) on cattle performance. In Experiment 2, an in vitro incubation study was used to determine the effect of organically complexed, sulfate, and oxide mineral sources on dry matter disappearance and culture pH when ruminal fluid donors were consuming water with no added sulfate (NS) or 2,000 mg/kg sulfate (WS). A level x source interaction (P = 0.01) was found for in vitro dry matter disappearance (IVDMD). Differences in IVDMD were found within ground com (P = 0.01) and com starch (P = 0.04) substrate groups when donors were consuming NS water. With the addition of sulfate to donor drinking water, IVDMD differences (P - 0.003) were only found within treatments with ground corn as a substrate. Differences (P - 0.02) in culture pH were noted when com starch was used as a substrate and donors were consuming NS water. With the addition of sulfate to donor drinking water, differences were noted for culture pH when substrates included ground corn (P - 0.03) and alfalfa (P = 0.02). In Experiment 3, an in vitro study was conducted to determine whether sulfur affected thiamin disappearance. Sulfur was introduced to tubes containing ground com and ruminal fluid. Sulfur was added as sulfate, sulfide, sulfite, or L-cysteine. Tubes treated with sulfate had higher (P < 0.01) thiamin concentrations than tubes tested with cysteine at 0 h. Sulfide had higher (P = 0.04) thiamin concentrations than cysteine at 0 h. No differences in thiamin concentration were found for sulfrir source at 24 (P = 0,06) or 48 h (P = 0.35). At 0 h, tubes with 0.0, 0.5, and 1.0 mg S/mL ruminal fluid had lower (P < 0.01) thiamin concentrations than treatments with 0,25 mg/mL. At 24 h, 0.25 mg/mL treatments had lower (P < 0.01) thiamin concentrations than the other three treatments. At 48 h, thiamin concentrations were higher (P = 0.02) for 0.0 mg/mL than 0.25 and 0.5 mg/mL, lower (P < 0.01) than 1.0 mg/mL treatments. Tubes treated with 0.25 and 0.5 mg/mL did not differ (P = 0.11), but had lower (P < 0.01) thiamin concentrations than 1.0 mg/mL treatments.Item Effect of Protein Supplement Sources on Intake and Digestion of Steers Fed Low-quality Forage(2013-01-29) Stefan, Courtney ChanelPotential protein supplements to grazing cattle were evaluated in two projects. In the first project, Karanja seedcake samples were prepared and ruminally incubated using the in situ method to measure nutrient disappearance in cattle consuming low-quality forage. Organic matter and CP were fractionated by degradability into A, B, and C fractions. Organic matter fraction A degradability ranged from 59.6 to 89% (P < 0.05) for all the karanja seedcake samples. Fraction A of CP ranged from 61.6 to 96.2% degradability for all the samples (P < 0.05). Karanja seedcake samples were observed to contain highly degradable nutrients and our results indicate karanja seedcake may possibly be utilized in grazing cattle protein supplements, consequently increasing economic sustainability of biofuel production. In the second experiment, four non-protein nitrogen supplements were ruminally infused in steers consuming low-quality forage. Supplements included a 40% CP mineral mix (40MM), 60% CP mineral mix (60MM), 25% CP liquid (25L), or 35% CP liquid (35L). Protein provision stimulated forage OM intake and total OM intake for both liquid supplements. Forage OM intake tended to be greater for the liquid supplements; 25L (P = 0.06) and 35L (P = 0.08), then control. Total OM intake significantly increased (P < 0.01) for both liquid supplements, when compared to the control treatment. Total digestible OM intake was greater (P < 0.01) for 25L (3.4 kg/d) and 35L (3.36 kg/d) than control (2.94 kg/d). Forage and total OM intake were not significantly affected by 40MM or 60MM treatments. Total tract digestions (OM and NDF) were not observed to be significantly different (P ? 0.11) between supplements and control. Ruminal ammonia was greater (P < 0.01) for all supplements then control and total ruminal VFA concentrations increased from 84.7 to 98.7 mM for control versus supplemented. Supplementation with liquids had a significant effect on intake. Our results indicate of the four supplements, liquid supplements improved the utilization of low-quality forage by cattle, thus improving nutrient stewardship.Item Effects of heat stress and lasalocid on the acid-base balance of cattle(Texas Tech University, 1989-12) Miller, Mark DouglasTwo questions were proposed in these studies. One, does lasalocid contribute to respiratory alkalosis and thus to bloat? Two, are there mechanisms of action other than the typical ruminal effects? Lambs, broilers chicks and steers were used in a series of studies to determine the effects of lasalocid, mineral ratio and heat stress on acid-base balance, nitrogen utilization, mineral balance, performance (average daily gain and feed efficiency), hematological variables and ruminal passage rates.Item Effects of hydroxy methyl-thio buanoic acid (Alimet) on performance and carcass characteristics of finishing beef cattle and on fermendation in a contiuous culture system(Texas Tech University, 2006-12) Wilson, Kristopher R.Three experiments were conducted to evaluate the effects of feeding graded levels of hydroxy methyl-thio butanoic acid (HMB); (Alimet; Novus Int., Inc., St. Louis, MO) on feedlot performance and carcass characteristics of finishing beef steers and on fermentation in a continuous-culture system. In Exp. 1, 160 steers (average BW; 384.9 kg; SD = 26.9 kg ) were blocked by body weight (BW) into eight blocks and assigned to four dietary treatments in a randomized complete block experimental design. The following four diets were fed, 1) Control, (0% Alimet); 2) 0.069% Alimet; 3) 0.137% Alimet and 4) 0.204% Alimet. Final BW decreased linearly (P = 0.069), adjusted final BW decreased linearly (P = 0.063) and average daily gain decreased linearly (P = 0.099) as the percentage of Alimet in the diet increased. No significant (P > 0.10) linear or quadratic effects of Alimet dose were noted for any of the carcass measurements collected in this study In Exp. 2, 80 steers (average BW 431.5 kg; SD = 42.2 kg) were blocked by BW into eight blocks and assigned to two dietary treatments in a randomized complete block design. Treatment diets were a Control (0 % Alimet) and an Alimet diet, with increasing concentrations of Alimet until 15 g/steer daily was achieved. Dry matter intake in the Alimet group tended (P = 0.132) to differ from intake than Controls. Gain:feed ratio was less (P = 0.046) with Alimet added to the diet than for Control for the d 0 to 56 period. No differences were detected in carcass measurements between the two treatments. A continuous culture system was used to determine the effects of Alimet on ruminal fermentation in Exp. 3 in two dietary treatments: Control (0% Alimet) and Alimet (0.24% Alimet). No ruminal digestibility, pH, ammonia, or fatty acid differences where were detected in Exp. 3; however, the molar proportion of valerate was greater (P = 0.05) for Control vs. Alimet. There also was a trend (P = 0.12) for a greater acetate:propionate ratio for the Control cultures. Results suggest that Alimet has the potential to be used as an intake limiting/control agent for use with finishing beef cattle fed high-concentrate diets based on steam-flaked corn. However, a better understanding of the cause for decreased DMI by finishing beef cattle fed Alimet is needed.Item Effects of optaflexx (ractopamine hydrochloride) on performance, rate and variation of intake, and acid-base balance in feedlot cattle(2006-05) Abney, Cassie S.; Galyean, Michael L.; Vogel, Gary J.; Albin, Robert C.; Wester, David B.Research was conducted to determine the effects of Optaflexx (OP) in feedlot cattle. In Exp. 1, a 3 x 3 factorial was used to study optimal dose (0, 100, or 200 mg•steer-1•d-1) and duration of feeding (28, 35, or 42 d) of OP in a randomized complete block design (n = 360; BW = 545 ± 33 kg). As OP dose increased, there was a linear increase in final BW (FBW; 1.6%; P = 0.011), average daily gain (ADG; 18.2%; P < 0.001), and gain-to-feed ratio (G:F; 15.6%; P < 0.001). As duration of feeding increased, there were quadratic (P = 0.04) and linear (P < 0.004) effects on ADG, with tendencies (P < 0.10) for quadratic effects for FBW, dry matter intake, and G:F. Hot carcass weight increased linearly (1.9%; P = 0.016) as dose of OP increased. Increasing dose of OP from 0 to 200 mg•steer-1•d-1 and duration of feeding from 28 to 42 d, improved feedlot performance, although quadratic responses for duration of feeding indicated little improvement as duration was extended from 35 to 42 d. In Exp. 2, 12 crossbred beef steers (BW = 593 ± 16 kg) were used in a completely randomized design to evaluate effects of OP (0 or 200 mg•steer-1•d-1) on rate of intake, daily deviation in intake, and acid-base balance. There were no differences in feedlot performance, urine pH, blood gas measurements, or daily deviations in intake between treatments; however, cattle fed OP at 200 mg•steer-1•d-1 had increased longissimus muscle area, decreased yield grade, and increased time to consume 50 and 75% of daily intake compared with control cattle. In Exp. 3, feed delivery data from three dose and duration trials were analyzed for day-to-day variation in feed deliveries. Based on analyses of adjusted absolute daily deviations in feed delivered, data indicated that OP did not affect daily variation; however, cattle tended to consume feed sporadically. These studies indicate that feeding OP for 35 d at 200 mg•steer-1•d-1 provided optimal improvement in feedlot performance, and that OP did not affect acid-base balance or variation in feed intake.
- «
- 1 (current)
- 2
- 3
- »