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Browsing Theses and Dissertations by Author "Ahola, Jason, advisor"
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Item Open Access Cattle as partners in conservation: the effects of grazing on indicators of rangeland health(Colorado State University. Libraries, 2018) Monlezun, Anna Clare, author; Rhoades, Ryan, advisor; Ahola, Jason, advisor; Brummer, Joe, committee member; Meiman, Paul, committee member; Turk, Phillp, committee memberFor centuries, the natural ecology of rangelands has supported large herds of herbivores. The partnership between these herbivores and the land has usually been, and can continue to be a sustainable one. However, the debate over the use of public lands for cattle grazing continues to intensify. Scientific literature and corresponding recommendations regarding cattle management on rangelands are conflictual. This thesis proposes that the resolution is not to remove grazing from rangelands, but to effectively manage grazing for specific landscapes and ecosystem types. Grassland ecosystems are highly dynamic and maintained by continuous adaptation to biotic and abiotic events. Therefore, strategic grazing management that also incorporates dynamic adaptation to environmental conditions may produce successful outcomes with respect to cattle grazing and sustainable land management. The objective of this study was to compare selected indicators of rangeland health in ungrazed areas to adjacent areas where strategic grazing management had been implemented. It was hypothesized that compared to areas excluded from grazing, areas where strategic grazing was implemented would exhibit: increased nutrient cycling by integration of organic carbon and nitrogen into the soil, increased abundance of native graminoids and native forbs, and reduced abundance of noxious weeds. It was hypothesized that forage quality would follow a particular pattern because of grazing: a decrease in forage quality shortly following grazing, an increase in forage quality with a period of rest, and a decrease in forage quality with continued absence of grazing. Paired grazed and ungrazed areas were established in 6 pastures across a grassland valley on Colorado's Front Range, which had not been grazed for at least 10 years. In 2016, baseline data were collected from both grazed and ungrazed areas prior to grazing. Subsequent data were collected in 2017, following strategic grazing management and adequate rest. Linear mixed models were used to compare differences between grazed and ungrazed areas. Results indicated no significant differences in soil organic carbon (P = 0.97), total nitrogen (P = 0.64), relative abundance of native graminoids (P = 0.15) or relative abundance of forbs/subshrubs (P = 0.74) between grazed and ungrazed areas. In regards to forage quality, crude protein was lower (P = <0.01) and neutral detergent fiber was higher (P = 0.05) at the conclusion of the grazing period, but acid detergent fiber did not differ (P = 0.51) in grazed versus ungrazed areas. Additionally, areas that were grazed in the spring and received 2-3 months of rest demonstrated higher forage quality than areas that were grazed in the fall and received 9-10 months of rest as indicated by higher crude protein (P = 0.03), and a tendency for lower neutral detergent fiber (P = 0.06), but no difference in acid detergent fiber (P = 0.97). Chi-square tests for soil and vegetation variables detected no variation between pairs of grazed and ungrazed areas across the landscape. This suggested that the biological variability within and between grazed and ungrazed areas was minimal, and that the strategic grazing regime, which incorporated flexibility in grazing intensity, stocking density, and season of grazing, produced homogeneous effects across all pastures. The results of this study indicated that one year of strategic grazing does not significantly affect select soil and vegetation variables and that further study is needed in order to inform application. As part of a long-term project, this collection of data and analysis was important for the initiation of a collaborative monitoring process, which will eventually determine if strategic grazing management proves to be helpful or harmful for land management goals. Continued research will aid ranchers and land managers in developing collaborations so that cattle might serve as partners in the conservation of rangelands, while maintaining animal performance and beef production objectives. Effective livestock management is key. Therefore, the human decision-making dimension is imperative to incorporate in future grazing studies.Item Open Access Effect of delaying time of AI based on Estrotect patch status on pregnancy rates of beef heifers and nursing beef cows(Colorado State University. Libraries, 2015) Markwood, Matthew, author; Peel, Kraig, advisor; Ahola, Jason, advisor; Whittier, Jack, committee member; Hadrich, Joleen, committee memberFour studies were conducted to evaluate the efficacy of a delayed timed AI (TAI) protocol. The objective was to evaluate the use of Estrotect patch status to determine optimum TAI implementation. Experiment 1 was conducted with, 997 cows across 6 locations were administered a 7-d CO-Synch + controlled internal drug release (CIDR) estrous synchronization protocol. The experimental design was a 2 x 2 factorial; factors were patch status at 58 h post PGF2α injection (activated or inactivated) and time interval from PGF2α to TAI (58 or 76 h). Patch status was characterized at 58 h post PGF2α into 4 scores: 1 = 0% activated, 2 = 50% activated, 3 = 100% activated, and 4 = missing. Females with a patch status of 3 were considered to be activated and females with patch status of a 1 or 2 were considered to be not activated. Females with missing patches were removed. There was no treatment x location interaction for pregnancy rate (P = 0.96), so data were pooled across locations. There was a tendency (P = 0.07) for an interaction between the main effects for pregnancy rate. Pregnancy rate was greater (P < 0.01) in cows with activated patches at 58 h post PGF2α (67.0%) compared to those with inactivated patches (51.1%). There was no difference (P = 0.99) for pregnancy rate when comparing the 58 (59.9%) vs. 76 h PGF2α to TAI interval (58.7%). Pregnancy rates for cows with a patch status of 3 at 58 h post PGF2α were greater (P < 0.05) than cows with a patch status of 1 or 4 and tended (P = 0.09) to be greater than cows with a patch status of 2. Cows with a patch status of 1 tended (P = 0.06) to have increased pregnancy rates by delaying TAI to 76 h post PGF2α. Although, it was not different (P = 0.13), there was a 7.4 percentage point increase in pregnancy rates for cows with inactivated patches that received TAI at 76 vs. 58 h. Experiment 2 was conducted to evaluate delayed TAI on 1,682 heifers across 3 locations. The objective was to evaluate the use of Estrotect patch status at various recommended and delayed insemination times for a TAI protocol. Experiment 2a was implemented with 1,159 Bos taurus heifers synchronized using a 14 d melengestrol acetate (MGA) – PGF2α protocol. Estrotect patches were applied at the time of PGF2α injection and evaluated at the time of insemination. Heifers were subsequently assigned to 5 treatments: 1) recommended 72 h post PGF2α TAI with activated patches, 2) recommended 72 h post PGF2α TAI with inactivated patches, 3) 12 h delayed TAI with inactivated patches, 4)18 h delayed TAI with inactivated patches, and 5) heifers with missing patches. Experiment 2b was conducted with 449 Bos taurus heifers synchronized using a 14 d MGA – PGF2α protocol. Heifers were divided into 3 treatments: 1) recommended 72 h post PGF2α TAI with activated patches, 2) recommended 72 h post PGF2α TAI with inactivated patches, and 3) an 8 h delayed TAI with inactivated patches. Experiment 2c utilized 74 heifers synchronized with a 7-d CO-Synch plus CIDR protocol. All heifers had Estrotect patches applied at the time of CIDR removal and PGF2α injection. Patch status was evaluated 58 h post PGF2α injection on all heifers. This experiment was analyzed as a 2 x 2 factorial with patch status 58 h post PGF2α injection (activated or inactivated) and at the time of insemination (58 or 76 h). In experiment 2a, differences (P < 0.05) in pregnancy rates were different by patch status across treatments. Similarly, experiment 2b demonstrated resulted in differences (P < 0.05) in pregnancy rates when comparing the activated patch treatment to both the inactivated patch treatment and the delayed inactivated treatment. However, no differences (P > 0.05) were seen in either experiment 2a or 2b when comparing the recommended inactivated patch treatments to any of the delayed inactivated patch treatments regardless of delay interval. Experiment 2c demonstrated a tendency (P = 0.07) for the interaction pregnancy rates to be increased when activated patches at 58 h were inseminated at 58 h post PGF2α injection and when inactivated patches at 58 h were inseminated at 76 h post PGF2α. Pregnancy rates for the main effects of patch status (P > 0.05) and interval inseminated (P > 0.05) did not differ. Results show a definitive increase in pregnancy rates when comparing heifers with activated patches to heifers with inactivated patches. However, delaying insemination time of heifers with inactivated patches did not increase pregnancy rates.Item Open Access Effects of monensin sodium and plant extracts containing cinnamaldehyde, capsicum oleoresin, and eugenol on days to puberty, gain, pregnancy rate, and feed efficiency in developing beef heifers receiving a high roughage diet(Colorado State University. Libraries, 2014) Bigler, Bo, author; Peel, Kraig, advisor; Ahola, Jason, advisor; Whittier, Jack, committee member; Holt, Tim, committee memberTo view the abstract, please see the full text of the document.Item Open 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 memberTwo 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.Item Open Access Effects of trace mineral source and concentration on production parameters throughout one cow-calf production cycle(Colorado State University. Libraries, 2023) Hallmark, Harrison, author; Engle, Terry, advisor; Ahola, Jason, advisor; Garry, Franklyn, committee memberAn experiment was conducted to evaluate the effects of Cu, Zn, and Mn supplementation on mineral status, production parameters, and cattle performance in a rangeland environment throughout a one -year period in eastern Colorado. One hundred and eighty multiparous crossbred (Angus and Angus x Hereford) beef cows were blocked by body weight, age, and gestational status and randomly assigned to 1 of 3 free-choice mineral treatments (n = 60 cows per treatment). Treatments were then assigned to 1 of 9 replicates (n=20 cows per replicate), resulting in 3 replicates per treatment. Treatments consisted of, 1) 1X NASEM (2016) sulfate base source, 2) 1X NASEM (2016) Intellibond source, or 3) 0.5X NASEM (2016) Intellibond source. Treatments 1 (1X Sulfate) and 2 (1X Intellibond) contained 1,000, 2,000, and 3,000 mg/kg DM of Cu, Mn, and Zn, respectively. While treatment 3 (0.5X Intellibond) contained 500, 1,000, and 1,500 mg/kg DM of Cu, Mn, and Zn. All free-choice mineral supplements were formulated to provide 0.15% supplemental S, 15 mg/kg Co from Co carbonate, and 55 mg/kg I from Ca iodate (Hubbard Feeds; Mankato, MN). Supplement consumption was formulated for 113 g·animal-1 ·d-1. Supplement intakes were determined every 28 d. Liver biopsies and blood samples were obtained before the experiment was initiated (d -45), after calving (d 158 and 159), and after weaning (d 294) at the end of the first production year. Each replicate was rotated to a different pasture every 2 to 4 weeks to minimize pasture effects. Cows were weighed during each liver biopsy event and at each scheduled handling events. A two-day calf weaning weight was collected during weaning (d 260 and 261). Over the first year of the experiment, cow BW, BCS, mineral status, mineral intake, and calf weaning weight were collected. There was no impact of treatment on any of the response variables measured during the first year of the experiment.Item Open Access Effects of two-stage weaning with nose flaps applied to calves on cow performance, calf performance, carcass quality, calf humoral immune response, and fertility(Colorado State University. Libraries, 2015) Lippolis, Katy, author; Ahola, Jason, advisor; Engle, Terry, committee member; Callan, Rob, committee member; Swyers, Kelcey, committee memberTo view the abstract, please see the full text of the document.Item Open Access Evaluation of the All Heifer, No Cow beef production system to improve beef production efficiency(Colorado State University. Libraries, 2019) Harrison, Meredith Ann, author; Ahola, Jason, advisor; Seidel, George, committee member; Mooney, Daniel, committee member; Archibeque, Shawn, committee memberTo view the abstract, please see the full text of the document.Item Open Access Measuring and managing pain and stress associated with castration in cull beef bulls(Colorado State University. Libraries, 2012) Repenning, Paul English, author; Ahola, Jason, advisor; Callan, Robert, committee member; Whittier, Jack, committee member; Engle, Terry, committee member; Fox, J. Trent, committee memberThe objectives of this research were to evaluate the effects of: 1) castration, 2) castration method (band vs. surgical) and 3) use of analgesia on measures of behavior, feedlot performance, and physiological responses in cull bulls. In the first study, Angus, Hereford, and Angus crossbred bulls (n = 20; initial BW = 384 ± 59.3 kg; 336 ± 20.1 d old) were housed in feedlot pens equipped with the ability to measure individual daily feed intake. A balanced randomized block design using a 2 × 2 factorial arrangement of treatments was utilized. Factors included: 1) castration method (band vs. surgical), and 2) analgesia presence. A multimodal analgesia protocol (MMA) was used and consisted of subcutaneous ketamine-stun containing butorphanol (0.01 mg/kg), xylazine (0.02 mg/kg), ketamine (0.04 mg/kg), and a local 2% lidocaine hydrochloride anesthetic block of the spermatic cords (10 mL per cord) and scrotum (10 mL) on d 0. Flunixin meglumine (1.2 mg/kg) was also administered intravenously (iv) on d 0, 1, 2 and 3 to MMA cattle. Cattle were stratified to treatments based on breed, BW, age and a temperament score. Treatments included: 1) band castration without analgesia (BAND), 2) band castration with analgesia (BAND-MMA), 3) surgical castration without analgesia (SURG), and 4) surgical castration with analgesia (SURG-MMA). All castrations were performed on d 0. Chute exit velocity (EV) and time in chute (TIC) were collected on d -9, 0, 1, 2 and 13. Willingness-to-enter-chute (WTE) score, rectal temperature (TEMP), heart rate (HR), and respiration (RESP) were collected on d 0, 1, 2, 3 and 13. Cattle were weighed on d -9 and 13 while feeding behaviors were collected continuously for 57 d pre-castration and 28 d post-castration. There was a tendency (P < 0.09) for ADG to be greater in cattle receiving analgesia. Both SURG treatments exhibited greater TEMP on d 1 (P < 0.001) and 2 (P < 0.05) compared to both BAND treatments. Mean DMI post-castration was greater (P = 0.02) in MMA treatments compared with non-medicated treatments. Meal duration was greater (P < 0.05) in both BAND treatments than in surgical castrates in wk 1 post-castration. Results suggest that pain mitigation reduces the impact of castration on ADG and DMI. The second study was comprised of 2 experiments. In Exp. 1 Angus and Charolais-crossbred bull calves (n = 127; 309.8 ± 59.04 kg) and in Exp. 2 Hereford, Angus, and Hereford × Angus crossbred bulls (n = 30, 300.8 ± 4.96 kg), were stratified by BW and randomly assigned to 1 of 3 treatments: 1) band castration (BAND), 2) band castration with oral administration of meloxicam (BAND-MEL), and 3) sham castration (SHAM). The BAND and SHAM procedures were completed on d 0. The SHAM treatment consisted of all animal manipulations associated with band castration without band application. Meloxicam was administered on d -1, 0, and 1 (1.0 mg/kg, 0.5 mg/kg and 0.5 mg/kg, respectively) via an oral bolus. Body weight and a subjective chute score (CS) were collected on d -1, 0, 1, 7, 14, 21 and 28 (Exp. 1 only). In Exp. 1, jugular blood samples were collected immediately before castration and 24 hr post-castration for Substance P (SP) analysis. In both experiments, video documentation on d 0 was used to determine range of vertical head motion (DIST) on a subset of animals during treatment administration. In both experiments, ADG was similar (P > 0.10) between BAND and BAND-MEL, but ADG in SHAM cattle was greater (P < 0.001) and tended (P = 0.07) to be greater in castrates in Exp. 1 and 2, respectively. In Exp. 1, CS did not differ (P > 0.10) between BAND and BAND-MEL on any d, but castrates exhibited greater CS on d 1 and 28 than SHAM cattle. In Exp. 2, CS was not affected (P > 0.10) by castration or the presence of meloxicam. In Exp. 1, DIST did not differ (P > 0.10) between BAND and BAND-MEL, but when pooled, castrates exhibited greater (P = 0.04) DIST than SHAM. In Exp. 1, plasma SP concentrations did not differ (P > 0.10) across treatments. Results indicate no impact of meloxicam administration on performance or behavioral and physiological responses to band castration. However, there was an impact of castration on ADG and CS.Item Open Access Pain evaluation and mitigation in the bovine(Colorado State University. Libraries, 2014) Yager, Alexandra Lee, author; Ahola, Jason, advisor; Peel, Richard, committee member; Whittier, Jack, committee member; Callan, Robert, committee memberTo view the abstract, please see the full text of the document.