Behavior of Holstein and Holstein-Gyr lactating cows supplemented with oregano and green tea extracts: Plant extracts for lactating cows

Abstract

Plant extracts have been fed as additives to domestic animals, but their effects on behavior are variable, although synergism between products is rarely explored. This study aimed to evaluate the effects of oregano (Origanum vulgare) and green tea (Camellia sinensis L.) extracts fed separately or associated as additives on behavior in lactating dairy cows. Thirty-two Holstein and Holstein-Gyr cows were distributed in 4 groups of 8 animals: control (CON) – without plant extracts; oregano extract (OR) – addition of 0.056% of oregano extract in the diet dry matter (DDM); green tea (GT) – addition of 0.028% of green tea extract in DDM; and mixture (MIX) – addition of 0.056% of oregano extract and 0.028% of green tea extract in DDM, following a randomized block design with time-repeated measurements. The trial lasted 58 days. There was no treatment by day interaction for any of the variables, but block by treatment interaction was significant for eating time. In Holstein cows, GT and OR decreased eating time compared with cows in CON. Compared to CON, OR reduced eating rate, while GT increased time spent standing and the number of social interaction events between cows. There were not additive effects of feeding extracts associated, except for rumination time and the number of non-agonistic interactions. Cows in MIX spent less time ruminating compared with cows in GT and engaged more non-agonistic events compared with cows in OR. Cows in MIX tended to have more drinking bouts than cows in GT and OR, and tended to eat less feed than cows in GT. Oregano and green tea extracts did not disturb feeding behavior, feed intake and milk production when fed separately to lactating dairy cows. When oregano and green tea extracts were fed associated, cows tended to reduce feed intake and resting time, and decreased ruminating time. Therefore, its association is not recommended. Considering their potential benefits evidenced in other studies on health, redox status and mitigation of methane emissions, as well as the absence of negative effects on feed intake, behavior and milk production, oregano and green tea extract may be used separately for lactating cows.