Objective: To investigate the extent of using dual-purpose wheat for grazing by late-pregnant and lambing ewes in southern New South Wales (NSW) and the effect on ewe health.
Methods: A questionnaire was mailed to sheep producers in the mixed-farming districts of the Hume Livestock Health and Pest Authority area in NSW, seeking information on whether there had been grazing by late-pregnant or lambing ewes of dual-purpose wheat during the period 2005-10. Information collected included general farm operation details, as well as the producers' experiences specific to grazing reproducing ewes on wheat, including causes and extent of disease and the producers' supplementation practices.
Results: Of the 202 respondents to the survey, 43% identified that they had grazed late-pregnant and/or lambing ewes on dual-purpose wheat during the period 2005-10. Of the producers, 71 had grazed reproducing ewes on wheat in 2010 and reported a mean disease incidence of 2.6% (range, 0.0-21.3%). Dystocia, pregnancy toxaemia, foot abscess and grass tetany were the most commonly reported diseases in ewes grazing wheat in 2010. The majority of producers (92%) supplied supplement to ewes grazing wheat in 2010, including mineral supplements (85%), roughage (58%) and grain (18%). Thirty percent of producers who grazed ewes on wheat between 2005 and 2009 experienced higher than normal rates of ewe health problems, reporting a mean of 7.9% ewes in these flocks with health problems.
Conclusion: Metabolic diseases such as pregnancy toxaemia, hypocalcaemia and grass tetany appear to be important diseases of reproducing ewes grazing wheat pasture.
Keywords: Grass tetany; hypocalcaemia; hypomagnesaemia; metabolic diseases; pregnancy toxaemia; sheep production.
© 2013 Australian Veterinary Association.