Effect of canola oil supplementation level on total tract digestion, ruminal fermentation, and methane emissions of cows grazing Urochloa sp. supplemented with a fixed amount of concentrate

Tropical Animal Health and Production (2023) 55:77 https://doi.org/10.1007/s11250-023-03485-8 REGULAR ARTICLES Effect of canola oil supplementation level on total tract digestion, ruminal fermentation, and methane emissions of cows grazing Urochloa sp. supplemented with a fixed amount of concentrate Jonathan Noe Avilés‑Nieto1 · Claudia Cecilia Márquez‑Mota1 · Juan Hebert Hernández‑Medrano2 Jacinto Efrén Ramírez‑Bribiesca3 · Epigmenio Castillo‑Gallegos4 · Alejandro Plascencia5 · Francisco Alejandro Castrejón‑Pineda1 · Luis Corona1 · Received: 28 January 2022 / Accepted: 23 January 2023 © The Author(s) 2023 Abstract Four rumen-cannulated cows (Bos taurus × Bos indicus, 657 ± 92 kg body weight, BW) in a rotational grazing (Urochloa sp.) system were assigned to different canola oil (CO) inclusion levels, 0.0, 0.40, 0.80, and 1.2 g/kg according to shrunk body weight (SBW, BW adjusted for gastrointestinal filling) in a 4 × 4 Latin Square design to evaluate CO on the CH4 emissions and dietary energy intake. C H4 emissions were estimated using an infrared analyzer methodology (Sniffer method). Grass intake and fecal production were estimated using Cr2O3 as an external marker. CO supplementation increased (linear effect, P ≤ 0.05) total dry matter and gross energy intake with a linear increase (P = 0.09) in neutral detergent fiber (NDF) intake. While digestible energy (Mcal/kg) linearly increased with increasing CO supplementation level (linear effect, P < 0.05), total tract digestion of organic matter, NDF, and CP was comparable (P > 0.05) between levels. Maximal CO supplementation (1.2 g/kg SBW) significantly decreased total ruminal protozoa population, acetate:propionate ratio, and enteric methane production (g/kg DMI) by 9, 5.3, and 17.5%, respectively. This study showed that, for cows grazing tropical forages, CO can be supplemented up to 1.2 g/kg SBW (5.8% of the total diet) without negatively affecting intake and nutrient digestion while reducing ruminal fermentation efficiency and enteric methane emission (≤ 17.5%). Keywords Methane · Canola oil · Cattle · Grazing · Digestion Introduction * Luis Corona 1 Facultad de Medicina Veterinaria y Zootecnia, Departamento de Nutrición Animal y Bioquímica, Universidad Nacional Autónoma de México, Ciudad de México, México 2 Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada 3 Departamento de Ganadería, Colegio de Postgraduados, Campus Montecillo, Estado de México, México 4 Facultad de Medicina Veterinaria Y Zootecnia, Centro de Enseñanza, Investigación Y Extensión en Ganadería Tropical, Universidad Nacional Autónoma de México, Veracruz, Mexico 5 Facultad de Medicina Veterinaria y Zootecnia, Universidad Autónoma de Sinaloa, Culiacán, México Livestock is among the highest contributors to greenhouse gas (GHG) emissions, mainly methane ( CH4) globally, with extensive grazing production systems having the highest emissions (Hristov et al., 2013a; Herrero et al., 2016). The CH4 emission represents a significant loss of energy intake (Audsley and Wilkinson, 2014; Hristov et al., 2015). Therefore, the challenge is to develop diets and strategies to reduce CH4 emission by optimizing energy use in ruminant diets, consequently improving productive performance and reducing their environmental impact (i.e., global warming; McGeough et al., 2010; Wu et al., 2016). Previous reports have pointed out to the addition of lipids to reduce C H4 emissions in ruminants (Grainger and Beauchemin, 2011; Hristov et al., 2013b; Knapp et al., 2014; Martin et al., 2016). Unsaturated fatty acids (UFA) decrease CH4 emission by increasing propionic acid production and decreasing protozoa population and UFA hydrogenation 13 Vol.:(0123456789) 77 Page 2 of 10 (Bonilla and Lemus, 2012, Mata e Silva et al., 2017). These effects have been observed using long-chain (C18) UFAs (i.e., vegetable and fish oils; oleic (C18:1) and linoleic (C18:2)) and medium chain fatty acids (Patra, 2013; Yanza et al., 2021). Studies using CO supplementation in grazing cattle (46 g/kg CO sprayed onto Lolium perenne meadow grass; Piñares-Patiño et al., 2016) and a barley silage diet (75% of DMI with 4.6% CO; equivalent to 1.2 g oil/kg SBW; Beauchemin and McGinn, 2006) resulted in a decrease of 11% and 32% C H4 emissions, respectively. Moreover, in grazing cattle, there was a decrease in ruminal acetate:propionate ratio (Piñares-Patiño et al., 2016). It was suggested that the reduction in C H4 may be due to a decrease in feed intake and total DM digestibility of the tract as a direct consequence of the decrease in dNDF. The effects of oil supplementation have been reported primarily under temperate climate conditions with scarce reports for cattle under tropical grazing conditions. Tropical pastures have low dNDF, nitrogen (N), and energy concentration which have a detrimental effect on N utilization efficiency and carbon retention, causing an increase in the production of enteric CH4 in cattle grazed in tropical grazing systems. To reduce enteric CH4 emissions significantly in these conditions, a suitable GHG mitigation strategy is the use of concentrates supplemented with adequate amounts of vegetable oils to increase energy intake but with a minimal impact on forage dNDF. Mata e Silva et al. (2017) reported a 23% reduction in C H4 emissions in dairy cows (Holstein × Gyr) grazing Urochloa sp. and supplemented with 2.86 kg/day concentrate and 13.4% sunflower oil (0.73 g of oil/kg of body weight). However, these authors did not consider ruminal fermentation variables in their study. It is important to point out that oil supplementation at high levels in grazing cattle should be used carefully due to possible detrimental effects on ruminal digestible NDF (dNDF; Jenkins and Palmquist, 1984), low intestinal digestibility, and energy value of lipids (Zinn and Jorquera, 2007). In beef cattle, optimal FA digestibility is limited to a maximum lipid intake of 0.96 g/kg body weight (BW), representing an adequate value of energy in fat (Zinn and Jorquera, 2007). However, other studies have observed similar effects on CH4 at lower oils supplementation levels (~ 0.73 g/kg BW; Mata e Silva et al., 2017). Consequently, it is necessary to determine the optimal level of vegetable oil inclusion to reduce CH4 emissions without decreasing dry matter intake (DMI) and dietary energy use in grazing cattle under tropical conditions. In this context, this study aimed to evaluate the effect of the inclusion level of CO on nutrient digestibility, ruminal fermentation, and enteric C H4 emissions in grazing cattle under tropical conditions supplemented with a fixed amount of commercial concentrate. 13 Tropical Animal Health and Production (2023) 55:77 Materials and methods Location The study was carried out at the Center for Teaching, Research and Extension in Tropical Livestock (CEIEGT, FMVZ-UNAM), located in Tlapacoyan, Veracruz, Mexico (20°03′N and 93°03′W). T (...truncated)