A comparison of production, reproduction, and animal health for pastured dairy cows managed either conventionally or with use of organic principles

This study examined a seasonally calving pasture-based dairy herd in North Carolina divided into 2 groups of cows that were managed either organically or conventionally with regard to health standards. The herd consisted of Holsteins, Jerseys, and crosses of various percentages between those breeds. The study aimed to compare the effect of organic versus conventional treatment strategies on overall production, reproduction, and animal health across 4 calving seasons within a pasture-based system. There were no differences (P > 0.40) in milk production or milk components between the organic and conventional management groups, but breed group differences showed Holsteins producing at higher levels than Jerseys (P < 0.001). Holsteins, reciprocal F1 crosses between Holsteins and Jerseys, and crossbreds > 50% Holstein had higher milk production and protein and fat production than Jerseys or cows > 50% Jersey (all P < 0.05). Somatic cell score from the organic herd (3.09) was numerically lower than in the conventional herd (3.33; P = 0.45). Crossbred cows had (P < 0.05) higher 90-d pregnancy rates than purebred cows. Proportions of cows with clinical mastitis or milk fever were not different between the management groups. Incidences of other health events (blind quarters, cystic ovaries, lameness, metritis, respiratory issues, retained placenta, udder edema) were all low, each < 1.4% and collectively < 3.6% across groups. These results support the hypothesis that an organically managed herd can be competitive with a conventional herd in terms of production, reproduction, and animal health within a pasture-based system.