Performance and methane emissions in dairy cows fed oregano and green tea extracts as feed additives

Abstract

Plant extracts have been proposed as substitutes for chemical feed additives due to their potential as rumen fermentation modifiers and because of their antimicrobial and antioxidant activities, possibly reducing methane emissions. This study aimed to evaluate the use of oregano (OR), green tea extracts (GT), and their association as feed additives on the performance and methane emissions from dairy between 28 and 87 d of lactation. Thirty-two lactating dairy cows, blocked into 2 genetic groups: 16 Holstein cows and 16 crossbred Holstein-Gir, with 522.6 ± 58.3 kg of body weight, 57.2 ± 20.9 d in lactation, producing 27.5 ± 5.0 kg/cow of milk and with 3.1 ± 1.8 lactations were evaluated (means ± standard error of the means). Cows were allocated into 4 treatments: control (CON), without plant extracts in the diet; oregano extract (OR), with the addition of 0.056% of oregano extract in the dry matter (DM) of the diet; green tea (GT), with the addition of 0.028% of green tea extract in the DM of the diet; and mixture, with the addition of 0.056% oregano extract and 0.028% green tea extract in the DM of the diet. The forage-to-concentrate ratio was 60:40. Forage was composed of corn silage (94%) and Tifton hay (6%); concentrate was based on ground corn and soybean meal. Plant extracts were supplied as powder, which was previously added and homogenized into 1 kg of concentrate in natural matter, top-dressed onto the total mixed diet. No treatment by day interaction was observed for any of the evaluated variables, but some block by treatment interactions were significant. In Holstein cows, the mixture treatment decreased gross energy and tended to decrease the total-tract apparent digestibility coefficient for crude protein and total digestible nutrients when compared with OR. During the gas measurement period, GT and OR increased the digestible fraction of the ingested DM and decreased CH expressed in grams per kilogram of digestible DMI compared with CON. The use of extracts did not change rumen pH, total volatile fatty acid concentration, milk yield, or most milk traits. Compared with CON, oregano addition decreased fat concentration in milk. The use of plant extracts altered some milk fatty acids but did not change milk fatty acids grouped according to chain length (short or long), saturation (unsaturated or saturated), total conjugated linoleic acids, and n-3 and n-6 contents. Green tea and oregano fed separately reduced gas emission in cows during the first third of lactation and have potential to be used as feed additives for dairy cows.

Effect of Rumen Culture Adaptation to Origanum vulgare L. Essential Oil on Rumen Methane and Fermentation

“…The reduction in CH4 with the addition of OEO was consistent with the findings of others (Tekippe et al, 2011;Patra and Yu, 2012;Cobellis et al, 2015;Kolling et al, 2018) and could be attributed to the antimicrobial effects of the OEO on protozoa and methanogenic Archaea as reported by Patra and Yu (2012) and Paraskevakis (2018). Interestingly however, the reduction in CH4 was significant only when OEO was added to the adapted culture suggesting that microbial adaptation and/or modification played a role in OEO effect.…”

Effect of dried oregano (Origanum vulgare L.) plant material in feed on methane production, rumen fermentation, nutrient digestibility, and milk fatty acid composition in dairy cows

“…Hristov et al (2013) also reported lower apparent total-tract digestibility of NDF of about 2% units when feeding oregano plant material, irrespective of dose, but not for DM and OM. Kolling et al (2018) documented no effect of oregano extract on the apparent total-tract digestibility of DM, CP (tendency), and NDF. Thus, the decreased apparent total-tract digestibility of NDF, and presumably DM and OM, in our study might be explained by the fact that we replaced grass/clover silage with lower digestible oregano, rather than the effects of EO.…”

“…In vivo evidence on the effectiveness of oregano EO, as such, is not consistent (Wang et al, 2009;Hristov et al, 2013;Lejonklev et al, 2016;Kolling et al, 2018). The effectiveness might depend on the dosage and mode of inclusion (plant material or EO).…”

Nutritional applications and beneficial health applications of green tea and l‐theanine in some animal species: A review

“…At post-partum, the milk had less level of cholesterol and triacylglycerol up to the third week post-partum compared to control cows. Therefore, GTE may be used as a food additive (Kolling et al, 2018) for a sustainable environment. Holstein steers fed with diet containing 20% green tea waste silage showed increased plasma concentrations of vitamin A and E, which protects the cattle from oxidative damage (Nishida et al, 2006).…”

“…Green tea extract (GTE) was added (0.028% of dry matter) to the feed of lactating Holstein/Holstein-Gir dairy cows; however, the diet did not alter the milk yield or most of the milk characteristics but reduced the emission of methane gas. Therefore, GTE may be used as a food additive (Kolling et al, 2018) for a sustainable environment. Dairy cows were exposed to oxidative stress and fatty liver disease during the periparturient phase, and thereafter, the absorption of GTE (containing catechins with proven anti-inflammatory, anti-oxidative and hepatoprotective effects) in cattle plasma after intraruminal and intraduodenal administration was documented.…”