Effect of Conversion from Conventional to Organic Dairy on Milk Quality

Abstract: Organic fanning (O) is an alternative for friendly use of the environment in time of presupposed global climate changes. Possible impacts of O on raw cow-milk quality, composition and properties, as compared to conventional fanning (C), were evaluated in this paper. The C milk was used as reference versus O. There is still a lack of knowledge in this field. Bulk milk samples (BMSs) were investigated in conventional and conversion (to O) period in one Holstein (H) herd. Milk yield (MY) was reduced by 14.6 and 28.5%, respectively, so was the crude protein (CP) (3.17<3.25%). Lower milk urea in O farming (22.02<28.56 mg.100 ml -1; by 22.9%) is a normal phenomenon. Milk freezing point was a little better (C:O; -0.52504 < -0.52309C) in C farming. H herd BMSs from winter and summer seasons of one year were investigated in four O herds (n=16) and in one C herd (n=36). O herds grazed during summer and were fed total mixed rations (TMR) during winter, C herd was supplied TMR throughout the year. Nutrition was typical under the Czech Republic (CR) conditions. Average MY of O herds was 7037422 and of C herd 8900 kg per lactation. Significantly lower were fat (3.79<4.06%), CP and true protein (3.09<3.17%) and casein (2.54<2.66%) in O herds. Average lactose (4.92>4.82%) and whey protein were significantly higher. These facts together with significantly lower urea (19.53<40.39 mg.100 ml -1) and higher acetone (6.8>1.6 mg.l -1) indicated permanent energy and protein deficiency in O herd nutrition. Citric acid in O herds was insignificantly lower (8.45<8.76 mmol.l -1). It is necessary to improve the energy supply to the O herd. Somatic cell count (SCC) was significantly lower in C herd, both (C and O) had SCC at extra milk quality level (<300 ths.ml -1). Significantly higher Ca and Mg levels were detected in O milk (1257>1172 and 112.0>107.4 mg.kg -1; Hanus et al., 2008). Additional research is necessary to make more detailed assessment of O milk benefits.

Reference: Hanus, O., Brychtova, J., Gencurova, V., Pesl, J., Hulova, I., Vyletelova, M., Jedelska, R., and Kopecky, J. (2008). Effect of conversion from conventional to organic dairy farm on milk quality and health of dairy cows. Folia Veterinaria 52(3/4): 140-148.