Selected factors that influence profitability of feedlot cattle
Date
2010
Authors
Tibbetts, Gary K., author
Whittier, Jack C., advisor
Engle, Terry E., advisor
Field, Thomas G., committee member
Mortimer, Robert George, committee member
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Abstract
For the primary emphasis of this dissertation, twenty-three ranches were selected from ranch cooperators in a large scale Nebraska-based cattle system to establish baseline measurements for liver concentrations of trace minerals, disease titers, parasite load, percent morbidity and gain performance. Upon arrival at the feedlot blood, liver, and fecal samples were collected from approximately 10% of each ranch group. After all yr 1 cattle were harvested an 11 ranch subset of the original 23 ranches was selected based on ranch weaning practice for a second yr survey. In yr 2 all ranches shipped calves to the feedlot on the day of weaning and all fed a standardized free choice mineral containing organic trace mineral complexes (OTM) to cow calf pairs 45 d prior to weaning. Comparing yr 1 and 2 for the 1 ranches, percent 1st pulls decreased from yr 1 to yr 2. Carcass quality was decreased from yr 1 to yr 2. Liver Cu concentrations of calves at weaning increased from yr 1 to a yr 2 and Zn and Mn liver concentrations were similar across years. Across both years, higher liver Cu concentration was correlated with decreasing total pulls and increasing ADG and mortality tended to decrease as Cu concentration increased. Higher liver Mn concentrations tended to be correlated with lower total pulls. There was no correlation between liver Zn concentration and animal and health performance. In conclusion, allowing cow-calf pairs access to free-choice mineral containing OTM prior to weaning improved some aspects of feedlot health and performance. For a second paper feedlot performance records from the U.S. Meat Animal Research Center feedlot for 1993 through 2000, were analyzed to evaluate the impact of footrot on ADG and total days on feed. Records from the original pool of 36,755 bull, steer and heifer calves were sorted so that only steers that had a single footrot incidence and those with no other morbidities were included in the data set (7,100 steers). To roughly pattern these data to industry production practices, time of footrot insult during feeding was divided into three production periods; starting (0-60 d), growing (61-120 d) and finishing (121d - harvest). Records were evaluated to determine which limb was more likely to be affected with footrot. A total of 459 (6.5%) steers were treated for a single footrot incident. ADG for cattle experiencing a single footrot incident was decreased compared to non effected cattle. The production period of footrot onset impacted both ADG and total days on feed. Mean days on feed for the non-affected cattle was 262 d while mean days on feed for footrot affected cattle was 267 d (P<0.01). The impact of footrot on days on feed for the starting, growing and finishing periods was -9.9 d, +2.2 d and +14.3 d.
Description
Department Head: William R. Wailes.
Rights Access
Subject
weaning
beef cattle
trace mineral
footrot
feedlot health
trace mineral complex
Trace elements in animal nutrition
Beef cattle -- Nutrition
Feedlots -- Health aspects
Beef cattle -- Health