Ryegrass pasture combined with partial total mixed ration reduces enteric methane emissions and maintains the performance of dairy cows during mid to late lactation

Abstract

The inclusion of grazed pasture in dairy feeding systems based on a total mixed ration (TMR) reduces feed costs, benefits herd health, and reduces environmental impact. The present study aimed to evaluate the effect of ryegrass pasture combined with a partial TMR on enteric methane emissions, dry matter intake (DMI), and performance of dairy cows from mid to late lactation. The experimental treatments included 100% TMR (control), partial TMR + 6h of continuous grazing (0900-1500 h), and partial TMR + 6h of grazing that was divided into 2 periods of 3h each that took place after milking (0900-1200 h; 1530-1830 h). Twelve F1 cows (Holstein × Jersey; 132±44 DIM) were divided into 6 lots and distributed in a 3×3 Latin square design with 3 periods of 21 d (15 d of adaptation and 6 d of evaluation). Ryegrass (Lolium multiflorum Lam.) pasture was used, and the TMR was composed of 80% corn silage, 18% soybean meal, and 2% mineral and vitamin mixture, based on dry matter. The same mixture was used for cows with access to pasture. The total DMI, milk production, and 4% fat-corrected milk were similar for all cows; however, the pasture DMI (7.4 vs. 6.0kg/d) and grazing period (+ 40 min/d) were higher in cows that had access to pasture for 2 periods of 3h compared with those that grazed for a continuous 6-h period. Methane emission was higher (656 vs. 547g/d) in confined cows than in those that received partial TMR + pasture. The inclusion of annual ryegrass pasture in the diet of dairy cows maintained animal performance and reduced enteric methane emissions. The percentage of grazed forage in the cows' diet increased when access to pasture was provided in 2 periods after the morning and afternoon milking.

Effect of concentrate level on enteric methane emissions, production performance, and rumen fermentation of Jersey cows grazing kikuyu-dominant pasture during summer

“…Lassey (2007) reported that ruminant livestock, across different production systems, has a typical Ym range of 4 to 10%. Recently, a relative high Ym value of 9.2%, similar to that of the current study, was reported by Dall-Orsoletta et al (2016) where dairy cows in mid to late lactation on a partial TMR were allowed to graze Italian ryegrass for short periods. Furthermore, Ym values of ruminants fed diets containing tropical grass diets (such as kikuyu) can range between 8.4 to 11.4% (Kurihara et al, 1999;Tangjitwattanachai et al, 2015), but can also be as low as 4.9% (Noguera and Posada, 2017).…”

Carbon Footprint of Milk from Pasture-Based Dairy Farms in Azores, Portugal

“…We assumed a fixed factor for the calculation of enteric CH 4 emissions but in reality, these emissions have been shown, for some breeds, to vary with feed and size. Pasture-based feed can help reduce enteric emissions [58], in particular when legumes are present [59]. Milking cows fed with legumes silage (e.g., alfalfa silage) tend to produce up to 16% less milk with up to 14% more enteric CH 4 than cows fed with concentrated feed.…”

Performance, milk fatty acid composition and behaviour of high‐yielding Holstein dairy cows given a limited grazing period

“…Lower milk yield of cows receiving RT compared to C resulted in a lower daily yield of protein, but not fat. Milk fat concentration has previously been reported to increase (Fajardo et al, ), decrease (Dall‐Orsoletta et al, ; Morales‐Almaráz et al, ) or remain unaffected (Soriano et al, ; Vibart, Fellner, Burns, Huntington, & Green, ) when grazing was included in the diet of TMR‐fed cows. These differences may be a function of NDF intake, as pasture is typically higher in NDF than the TMR, which may be expected to increase milk fat concentration (Sutton, ).…”

“…Increasing the proportion of grazed pasture in the diet of dairy cattle can, however, offer economic, environmental, milk quality and animal welfare benefits (Hennessy, Delaby, Pol‐van Dasselaar, & Shalloo, )⁠. For example, grazing dairy cows for part of the day can lower farm expenses and increase profit in scenarios with high feed costs and low milk prices (Tozer, Bargo, & Muller, )⁠ and reduce the methane output of animals (Dall‐Orsoletta, Almeida, Carvalho, Savian, & Ribeiro‐Filho, ; Mufungwe et al, )⁠. Grazing may also increase the concentration of fatty acids (FA) in milk that are beneficial to human health (Barca et al, ; Mufungwe et al, ) and, because cows can exhibit motivation to be outside at pasture (Motupalli, Sinclair, Charlton, Bleach, & Rutter, )⁠, pasture access allows natural behaviour to be expressed which may potentially improve animal welfare.…”

“…Alternating grazing with TMR feeding between the am and pm milking intervals has also been reported to lower milk yield compared with housed and TMR‐fed cows (Bargo, Muller, Delahoy, & Cassidy, ; Soriano, Polan, & Miller, ),⁠ unless TMR was provided in the field (Mufungwe et al, )⁠. Recently, it has been reported that limiting the time cows have at pasture to 6 hr per day allows cows in mid‐to‐late lactation to graze pasture and consume sufficient TMR to maintain milk yield in comparison with housed and TMR‐fed cows (Dall‐Orsoletta et al, )⁠.…”