Metabolism and rumen microbiome evaluation of cattle fed supplementation of non-protein nitrogen or in mixed grass-legume pasture as methane emission mitigation strategy

• Ano de defesa: 2023
• Autor(a) principal: Oliveira, Gabriela Bagio
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Ex situ technique; Macrotyloma axillare (NO 279); Urochloa brizantha cv. Marandu; Ammonium nitrate supplementation; Continuous stocking; Estações do ano; Gases de efeito estufa; Greenhouse Gas; Lotação contínua; Seasons; SF6 tracer gas technique; Suplementação com nitrato de amônio; Sustainability of livestock; Sustentabilidade da pecuária; Técnica ex situ; Técnica do gás traçador SF6
• Link de acesso: https://www.teses.usp.br/teses/disponiveis/10/10135/tde-08122023-160838/

Objective of the study was to evaluate the of ruminal parameters and ruminal ecosystem of the cows on continuous grazing in mixed pastures of Macrotyloma Legume and Marandu Palisadegrass compared with commonly used systems based on pasture, i.e., Marandu Palisadegrass exclusive pasture (without or with supplementation). The experiment was carried out at Institute of Animal Science. The experiment lasted two consecutive years (October 2019 - August 2021) and data collection was carried in the middle of each season. The experimental design used was a randomized block design. The treatments: 1) Grass (G): Exclusive pasture of Urochloa brizantha cv. Marandu 2) Grass + Protein Supplementation (GP): Exclusive pasture of Urochloa brizantha cv. Marandu with ad libitum protein supplementation; 3)Grass + Legume (GL): mixed pasture with Urochloa brizantha cv. Marandu and legume Macrotyloma axillare (accession NO 279). Statistical analyses were performed using SAS 9.4 MIXED procedure, and a significant effect was considered when P&#8804;0.05 (Fisher&#8242;s test). Chapters 3 and 4. Six Jersey cows, nulliparous cows, with ruminal cannula and with an average weight of 372.83 kg (&#177; 44.62 kg) and 36 months old (&#177; 3 months) were used as experimental animals per year. Results: Nutritional value: CP (G = 8.25b , GP = 8.77b and GL = 10.70a %; P= 0.0042) and NDF (G = 69.09a, GP = 69.52a and GL = 65.03b%; P=0.0506). Dry matter intake: DMIsupplement (G = 0.17b , GP = 0.60a and GL = 0.13b kg/ani/day; P = 0.0019). Apparent digestibility: CP (G = 46.19c , GP = 74.55a and GL = 59.43b %; P &#60;.0001); Microbial nitrogen compounds synthesis (G = 65.99b , GP = 83.18a and GL = 55.22b g/day; P = 0.0391). Total count of protozoa (G = 162.7b , GP = 208.9a and GL = 201.1a x103 /mL; P = 0.0304). Balance of rumen ammonia (G = 3.36b , GP = 4.99a and GL = 3.80b mg/dL.h; P = 0.0040). Total SCFA: 4.68 &#177; 0.42 mol/kg.d. Methane production: 26.14 &#177; 2.27g/kg.day. Relative energy loss of methane in relation to the other rumen fermentation products (G = 23.55a , GP = 18.84b and GL = 18.97b ; P&#60;.0001). GE loss in the form of methane (G = 6.10a , GP = 5.12b , and GL = 5.15b %; P = 0.0031). Chapter 5: Twelve Jersey cows, nulliparous and with average weight of 372.83 kg (&#177; 24.74 kg) and with 36 months (&#177; 3 months) old were used as experimental animals per year. Results: ADG (G = 0.36b , GP = 0.61a and GL = 0.64a kg/day; P <.0001). FE (G = 0.041b , GP = 0.061a and GL = 0.067a kg/kg; P = 0.0097). Methane: CH4 (G = 269a , GP = 197b and GL = 234ab g/animal/day; P = 0.0062); CH4/ADG (= G = 1.09a , GP = 0.31b and GL = 0.37b kg/kg; P<.0001); CH4/DMITotal; (G = 26.63a , GP = 19.82b and GL = 22.44ab g/kg; P = 0.0037); Ym: (G = 8.38a ; GP = 6.34b and GL = 8.03%a , P=0.0026). The strategy of supplementing cows on Marandu grass pastures with Ammonium Nitrate as a non-protein nitrogen source, and the strategy of introducing Macrotyloma axillare (NO 279) in tropical pastures as an intercropped system, can play a significant role in reducing methane emissions and enhancing animal productivity in Brazil.