A comparison of conventional and organic dairy cows has led to questions over the efficacy of conventional dry cow therapy.
Organic cows showed no difference in incidence of mastitis or somatic cell count compared to conventionally farmed cows on the same farm, Newcastle University researchers told the British Society of Animal Science conference this week.
The study suggests conventional treatments have less effect as cows age, said Dr Catherine Douglas, one of the lead authors of the study.
“As conventional cows were older when they got mastitis it may suggest dry cow therapy protects them at a younger age but is less effective as they get older,” she said.
“Conventional cows were getting mastitis significantly later in lactation.
“It is proposed this could be due to better protection during the dry period but then they are susceptible later in lactation and it does not affect overall incidence.”
Organic cows got mastitis 18 days earlier, a “meaningful difference” according to Dr Douglas.
The conference was told that the study offered a good comparison as the same management and herdsman operated both herds across the University farm.
“Our farm has 95 managed organic cows and the same number of conventional cows, everything else is as similar as it possibly could be,” said Dr Douglas. “The farms have the same bulls and herd manager.”
Treatments were given at the same stage for both systems. Organic cows received a muscular injection of amoxicillin/clavulanic acid and conventional cows had an intramammary suspension of cefquinome.
At the dry period, organic cows with SCCs higher than 200,000 received intramammary suspension of penethamate hydriodide, procaine penicillin and framycetin sulphate. Conventional cows received intramammary suspension of cefalonium irrespective of SCC.
Source: The Dairy Site
