A new trial carried out at a Brazilian university during the hot season found that the 100 per cent natural oregano essential oil (OEO) feed additive Orego-Stim, from Anpario, increased milk yield and energy corrected milk yield in Jersey cows post-calving.
Supplementation of cow diets with the natural phytogenic was also found to significantly reduce somatic cell counts (SCC) and to cut the number of aggressive interactions between the cows each day pre-calving.
A total of 24 Jersey cows, weighing approximately 400kg and averaging 2.7 lactations, were split into one of three treatment groups from 21 days pre-calving to 21 days post-calving: a control group; an OEO supplemented group (10g per day of Orego-Stim Powder; and a Green Tea supplemented group (5g per day Green Tea extract). Body weight and body condition were measured weekly, with production and feeding behaviour assessed daily. Animal health and welfare was continuously monitored.
The results showed that pre-calving, cows fed OEO supplemented diets visited the feed trough less often, but also had fewer visits without eating and tended to spend more time ruminating than the other dietary groups. Cows receiving OEO supplemented diets also had significantly fewer aggressive episodes per day than the control group, with OEO fed cows demonstrating a 48 per cent lower incidence compared to the control.
Post-calving, cows receiving OEO tended to have a higher dry matter intake, a 16 per cent greater milk yield and a higher energy corrected milk yield than the control cows. Compared to Green Tea supplemented cows, OEO increased milk yield significantly by 35 per cent.
Anpario’s global innovation manager and ruminant technical specialist, David Wilde, commented said transition cows were particularly susceptible to increased disease challenge following disruption to feeding and social behaviours, increasing the risk of involuntary culling.
“When considering the improvements seen in this trial on performance, feeding behaviour and social interactions, OEO may help to support enhanced welfare of dairy cows during the transition period,” he added.
During the trial, blood samples were taken to determine the antioxidant status of the cows and the ability of the different dietary treatments to reduce dichlorofluorescein diacetate (DCF) oxidation, an indicator of levels of harmful free radicals, was assessed. The milk was also analysed for SCC.
“Measuring the SCC of milk can be a good indicator of cow health, with high levels suggesting infection, as well as causing an altered mineral flow in the udder which can result in a higher milk pH and reduced production,” Mr Wilde said. “The trial found that cows fed OEO supplemented diets had a significantly lower SCC, by 62 per cent and 50 per cent, compared to levels in milk from cows in the control or green tea groups respectively.
“Antioxidants can help to reduce incidence of oxidative stress, helping to support performance and immune function. For transition cows, antioxidant function is particularly important as these animals are highly susceptible to impaired immunity and increased disease prevalence, elevating the risk of poor performance or involuntary culling.”
The trial found that both OEO and green tea supplemented cows had significantly lower DCF oxidation both pre- and post-calving, demonstrating an increased antioxidant activity and a reduced level of oxidative stress compared to control cows. Post-calving, cows fed OEO also had significantly higher levels of the antioxidant glutathione (GSH), indicating reduced metabolic stress.
Natural, non-synthetic, OEO has been shown to contain more than 100 beneficial compounds that work synergistically to offer a multitude of benefits. Compounds such as ρ-cymene, carvacrol and thymol are acknowledged to have a role in appetite enhancement, offer antibacterial and antioxidant functions, which can support livestock during periods of heat stress, as well as providing effective immunomodulatory and anti-inflammatory properties.
NB: text orignally published on February 23, 2021. Updated on May 10, 2021 to include additional trial results on SCC.