ARS | Publication request: Effect of weather patterns on preweaning growth of beef calves in the Northern Great Plains

Submitted to: Agricultural Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 21, 2012
Publication Date: N/A

Interpretive Summary: Several studies have investigated effects of beef production on greenhouse gas emissions and consequent climate change. Here we turn the question around – how might climate change affect cow-calf production? Using data collected from 1935-2010, year-to-year variation in growth of sucking calves in the Line 1 Hereford population maintained by USDA-ARS at Fort Keogh Livestock and Range Research Laboratory, Miles City, Montana was retrospectively related to variation in weather. A general increase in temperature during the vegetative growing season that corresponds with the suckling period could decrease growth of calves from birth to weaning on the Northern Great Plains of North America. Results also were suggestive of potential for precipitation during late gestation to cause thermal stress on cows with downstream effects on progeny performance during the sucking period.

Technical Abstract: Beef production records collected over a 76-year investigation into effects of linebreeding and selection of Hereford cattle, and concurrent weather records were used to assess effects of weather patterns on the growth of calves from birth to weaning. Data were simultaneously adjusted for trends in the calf production data arising from selection and inbreeding, and for effects of age of dam and sex of calf to produce clean estimates of the year effects. Daily maximum and minimum temperatures were summarized to identify the first and last days of a 1500 growing degree growing season. Precipitation was accumulated from the end of the growing season the previous year through 31 December, 1 January through the beginning of the current year growing season, and during the current growing season. These weather records were then subjected to principal components analysis and the eight years characterizing the extremes in each of the five principal components were identified. Year effects on calf growth were contrasted for the pairs of eight years characterizing the extremes of each principal component. Irrespective of the pattern of precipitation prior to the growing season and with near or above average precipitation during the growing season, calves reared in years characterized by longer, cooler growing seasons gained more weight from birth to weaning than those reared in opposing years. In summary, this retrospective analysis indicates a general increase in temperature could decrease the growth of calves from birth to weaning on the Northern Great Plains of North America.