K.L.M. McLEOD, C.W. HOLMES, P.C.H. MOREL, K.R. DOWSON, A. THATCHER, N.M. SHADBOLT and T.C. KELLY
Proceedings of the New Zealand Society of Animal Production 68: 8-11
This study compared mastitis bacteriology and somatic cell counts (SCC) between an organic and a conventional dairy herd, each managed as a pastoral-based system, in the 2004/05 and 2005/06 seasons. Single quarter foremilk samples taken from both herds at calving, 14 days post-calving, mid-lactation and dry-off were cultured for bacteriological analysis. Individual cow SCC were obtained from monthly herd tests. The percentage of cows infected with Staphylococcus aureus and Streptococcus uberis was generally higher in the organic herd than the conventional herd. However, these differences were only significant for S. aureus at midlactation 2005/06, when 56% of the organic herd was infected compared to 23% of the conventional herd (P<0.05), and for Str. uberis at dry-off 2005/06, when 7% of the organic herd was infected but none of the conventional herd (P<0.001). The organic herd had a significantly higher mean lactation back transformed SCC than the conventional herd, in 2004/05 (96,921 vs. 75,608 cells/mL, P<0.05) and 2005/06 (103,968 vs. 63,096 cells/mL, P<0.0001). The 2004/05 season was the first time that a significant difference in mean SCC between the organic and conventional herds had been measured, since the organic and conventional dairy systems comparison trial was established in 2001.
Keywords: NZSAPAB; organic dairy system; conventional dairy system; mastitis
All rights reserved © New Zealand Society of Animal Production
Last modified: 2nd August 2008
All rights reserved © New Zealand Society of Animal Production
Last modified: 2nd August 2008