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YEAR TO YEAR VARIABILITY OF INDIVIDUAL COW DISTRIBUTION PATTERNS: IMPLICATIONS TO GENETIC IMPROVEMENT.
Author
Millward, Michael F.
Bailey, Derek W.
Thomas, Milt G.
Speidel, Scott E.
Enns, Mark
Howery, Larry
Publisher
Society for Range Management
Publication Year
2017
Body

Ongoing research suggests that cattle grazing distribution could be improved through genetic selection. One of the keys for this proposed management approach to be successful is that cattle grazing patterns should be relatively repeatable over time. The objective of this study was to determine the similarity of individual cow grazing patterns recorded during different years.� Seventeen mature Brangus cows were tracked from late January to mid-March 2015 in a 3700 ha pasture in the Chihuahan Desert.� As part of other studies, seven of these cows were tracked previously in this pasture during late June through July 2011, and the other 10 cows were tracked from December 2012 through January 2013.� Positions were recorded at 10 minute intervals using global positioning collars.� Two types of indices were used to describe cattle grazing patterns based on slope and horizontal and vertical distance to water.� One type of index used ratios comparing individual cow patterns to her contemporaries, while the other compared terrain use to expected grazing patterns based on literature reviews.� The correlation between the ratio-based rolling index from 2015 tracking and the previous tracking was 0.42 (P = 0.09).� The correlation of pasture use between the two tracking periods was 0.29 (P = 0.26).� Although the grazing patterns were recorded at least two years apart and during different months of the year, cattle that grazed pasture locations far from water during the first tracking period often used these areas during the second period. Although this initial study is promising, more research is needed to evaluate the repeatability of cattle grazing distribution patterns.�

Language
English
Resource Type
Text
Document Type
Conference Proceedings
Conference Name
SRM St. George, UT
Collection
SRM Annual Meeting Abstracts