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Theses and Dissertations

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Browsing Theses and Dissertations by Subject "ADG"

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    ItemOpen Access
    An evaluation of cattle handling categories in the beef quality assurance feedyard assessment, compliance of large feedyards with these guidelines, and influence of handling practices on behavior and performance of feedlot cattle
    (Colorado State University. Libraries, 2015) Woiwode, Ruth, author; Grandin, Temple, advisor; Archibeque, Shawn, committee member; Engle, Terry, committee member; Kirch, Brett, committee member; Paterson, John, committee member; Rollin, Bernard, committee member
    Animal husbandry and management practices were surveyed in commercial feedlots to document compliance of select feedlots with Beef Quality Assurance (BQA) guidelines for cattle handling under the premise that this data warrants inclusion in the National Beef Quality Audit (NBQA). The BQA Feedyard Assessment for cattle handling has not yet been fully validated, and this work partially substantiates the current assessment categories. The inclusion of this handling data is essential in order to continue the track record of identifying target areas where improvement is needed, and to document growth and positive performance. Collecting and reporting of survey data is part of the verification and ongoing monitoring process that characterizes an effective HACCP plan, which was the system for management that was adopted during formation of the BQA program. It has been said that producers manage what they measure, and systematic measurement of categories for cattle handling and husbandry practices in the BQA can yield valuable information to assist producers in making management decisions. The NBQA, which has been conducted in five year increments since 1991 has accomplished just that, through the identification of targets where improvement is needed, with corresponding recommendations for improvement. The growing repository of data, collected over the course of time, reflects adjustments the industry has made in an effort to continuously improve the quality and consistency of beef production, and thus increase consumer confidence. BQA is a voluntary program that allows the use of self-assessment or third party audits to ensure compliance with the guidelines of the program. The BQA Feedyard Assessment (FA) provides guidelines for cattle handling in commercial feedlots, and is a useful tool for measuring cattle handling practices. Using these guidelines, select feedlots in 3 states (Colorado, Kansas, and Nebraska) were assessed for six current BQA categories (electric prod use, falls, stumbles, jump and run, and chute operation). These states rank 5th, 3rd, and 2nd, respectively, among all states for the number of cattle on feed each year. These three states were selected based on their ranking among the top five states for number of cattle on feed, and for the high density areas of large (1000+ head) feedyards in each state, accounting for approximately 50% of all US fed cattle each year. The feedyards included in this study were all large (1000+ head capacity) yards, with a mean capacity of 34,000 head. Across 28 sites surveyed, rate of electric prod use was 3.8% vs. the 10% current BQA critical limit (CL); only 2 sites surveyed exceeded the CL with 15% and 45% respective rates; and 12 did not use an electric prod. The rate of cattle falling when exiting the squeeze chute was 0.6% vs. BQA CL 2%, and no site surveyed exceeded the CL. The rate of cattle stumbling when exiting the squeeze chute was 5.7% vs. BQA CL 10%, with 4 sites exceeding the CL and 4 sites that had no stumbles. The rate of cattle vocalizing was 1.4% vs. BQA CL 5%; for cattle that jumped or ran when exiting the squeeze chute, 52% vs. BQA CL 25%; and mean score for cattle that were improperly captured in the squeeze chute and not readjusted was 1.2%, vs. BQA CL 0%. A second study was conducted at a commercial feedlot in Kansas. The objective of this study was to investigate if a relationship exists between handling, and behavior and ADG of feedlot cattle. Upon arrival, Hereford steers (n = 496; initial BW = 304 ± 35.6 kg) of similar genetic background were sorted into four pens to determine the effects of handling on behavior and ADG. Two handling conditions prior to processing and two conditions of release from the squeeze chute were imposed. Prior to processing, handlers were required to quietly walk all steers from their home pen to the processing area (SLOW); or handlers were permitted to bring steers to the processing area in the normal fashion (FAST). Since this condition was applied to pens, pen was considered the experimental unit for the full model. Individual steers were randomly assigned to one of two conditions of release from the squeeze chute. The first was a delay no longer than 30 seconds following the completion of procedures to allow cattle to stop struggling (DELAY); the second was release immediately following the completion of procedures (NORM). Vocalization, chute temperament, exit speed and exit behavior scores were assigned to all steers during intake processing. Paired t-tests determined that cattle exiting the chute at a walk or trot vs a run tended (P=0.08) to have higher ADG. Cattle vocalizing during restraint had lower (P=0.04) ADG than those that did not vocalize. The FAST group showed a tendency to vocalize more frequently than the SLOW group. Pearson’s correlation analysis showed a significant, positive correlation between exit speed and vocalization (P= 0.0021, r= 0.14256), and a significant, negative correlation between exit speed and ADG (P= 0.0036, r= -0.13542). Using this approach, handling was correlated with behavior and ADG.
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    ItemOpen Access
    Effects of monensin sodium, plant extracts and injectable trace minerals on feedlot performance, fertility and morbidity of beef cattle
    (Colorado State University. Libraries, 2015) Fischer, Mariah, author; Ahola, Jason, advisor; Peel, Kraig, advisor; Seidel, George, committee member; Engle, Terry, committee member
    Two studies were conducted to evaluate the effects monensin sodium, plant extracts, and injectable trace minerals on heifer and bull fertility, and calf feedlot performance and morbidity. In the first study, Angus heifers (n = 107; 259.3 ± 21.0 d of age), blocked by weaning BW (262.7 ± 29.9 kg; d -19), were randomly assigned to treatments in a 2 x 2 factorial design, where all heifers received the same basal ration consisting of a 30% CP liquid supplement containing 200 mg/0.45 kg monensin sodium. Treatments were applied daily to the basal ration as topdressed supplements and were fed at a rate of 0.32 kg•hd-1•d-1. Treatments were as follows: 1) high level of monensin sodium (MON), where monensin sodium was topdressed at 200 mg•hd-1•d-1, 2) low level of monensin sodium plus the plant extracts cinnamaldehyde, capsicum oleoresin and eugenol (CCE), where plant extracts were topdressed at 11,000 mg•hd-1•d-1, 3) control (CON), low level of monensin sodium without topdressed supplements, or 4) high levels of monensin sodium with plant extracts (COMB), where monensin sodium was topdressed at 200 mg•hd-1•d-1 and plant extracts were topdressed at 11,000 mg•hd-1•d-1. In both studies, heifers were weighed and estrus detection patch status was recorded every 11 d. Age at puberty was determined by patch status and was recorded as the d the patch was first activated. A 14 d CIDR-PG-AI protocol was utilized to inseminate heifers, when heifers were 427.3 ± 21.0 d of age. In the 14 d CIDR-PG-AI, a controlled internal drug release device (CIDR) was inserted 33 d prior to AI and removed 14 d later. Prostaglandin was injected 16 d after CIDR removal, and heifers were inseminated 3 d later. Heifers were placed with bulls for natural service 21 d post AI. Pregnancy was determined 56 d post AI via ultrasound and 178 d post AI via rectal palpation. Calving records were used to validate ultrasound results. In the first study, there were no treatment main effects for initial or final BW (P > 0.05). There were no interactions between the main effects of monensin sodium fed at high concentrations and plant extracts for any feedlot or fertility performance variable (P > 0.05); however, there was a main effect of high levels of monensin sodium for heifer DMI from d 0 to 8 and d 8 to 15, where MON and COMB heifers had reduced DMI compared to CCE and CON heifers (P = 0.05). From d 11 to 22 and d 44 to 66, heifers that received plant extracts (CCE and COMB) had lower ADG than CON and MON heifers (P = 0.05). Feed efficiency tended (P = 0.08) to be improved in heifers fed high levels of monensin sodium (MON and COMB) compared to heifers fed low levels of monensin sodium (CCE and CON); however overall DMI, ADG, age at puberty and pregnancy rate were not affected by the main effects of high levels of monensin sodium or plant extracts (P > 0.05). In the second study, Angus bulls (n = 31, yr 1; n = 35, yr 2), heifers (n = 107) and steers (n = 105) were randomly assigned a treatment at weaning (278.6 ± 35.0 kg; 241.0 ± 19.6 d): 1) control (CON), no injection, or 2) injectable trace minerals (MIN), which included Cu, Zn, Se and Mn. The MIN treatment was administered at weaning (d 0) and again on d 64 (yr 1) and d 110 (yr 2) to bulls, and at weaning (d -19) and on d 135 to heifers. The second injections were 80 (yr 1) or 38 d (yr 2) prior to bull breeding soundness exams and 33 d prior to heifer AI. Steers received only the initial injection at weaning. Injections were administered at 1 mL/45.4 kg of BW at weaning and 1 mL/68.0 kg of BW prior to breeding soundness exams and AI, as per the product label. Bulls in both years exhibited no differences in overall ADG based on treatment (P > 0.05); however, MIN bulls had reduced ADG from d 64 to 113 (P = 0.05) versus CON. Steer and heifer ADG was not different across treatments (P > 0.05). Incidence of morbidity was not different among treatments for any class of cattle (P > 0.05). A licensed veterinarian performed the breeding soundness exams and Computer-Assisted Sperm Analysis was performed to analyze sperm motility, velocity, straightness and linearity objectively. Motility and morphology from breeding soundness exams were not effected by MIN (P > 0.05); however, in yr 2 there was a tendency for sperm from MIN bulls to have a higher percentage of secondary defects (P = 0.08). Sperm beat cross frequency was greater in CON in yr 2 (P < 0.01), and tended to be greater in CON in yr 1 (P = 0.10). Progressive velocity of sperm was greater in CON in yr 2 (P < 0.05). Neither BCS nor age at puberty in heifers was affected by treatment (P > 0.05). These results suggest there is no benefit to newly weaned calf performance or morbidity, or yearling bull or heifer fertility, when supplementing cattle with injectable trace minerals at weaning.