Effect of pregnancy and feeding level on voluntary intake, digestion, and microbial nitrogen synthesis in Zebu beef cows.

Autor: Gionbelli MP; Department of Animal Science, Universidade Federal de Lavras, Lavras, MG, 37203-202, Brazil. mateus.pg@ufla.br., de Souza Duarte M; Department of Animal Biosciences, University of Guelph, Guelph, ON, N1G 2W1, Canada., de Campos Valadares Filho S; Department of Animal Science, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil., Gionbelli TRS; Department of Animal Science, Universidade Federal de Lavras, Lavras, MG, 37203-202, Brazil., Ramirez-Zamudio GD; Department of Animal Science, Universidade Federal de Lavras, Lavras, MG, 37203-202, Brazil., Silva LHP; Department of Agriculture and Food Science, Western Kentucky University, Bowling Green, Kentucky, 42101-1066, USA., Nascimento KB; Department of Animal Science, Universidade Federal de Lavras, Lavras, MG, 37203-202, Brazil., Costa TC; Department of Animal Science, Universidade Federal de Lavras, Lavras, MG, 37203-202, Brazil.
Jazyk: angličtina
Zdroj: Tropical animal health and production [Trop Anim Health Prod] 2024 Jan 12; Vol. 56 (1), pp. 41. Date of Electronic Publication: 2024 Jan 12.
DOI: 10.1007/s11250-024-03888-1
Abstrakt: The objective of this research was to evaluate how pregnancy and feeding regimens affect the feed intake, digestibility, and efficiency of microbial nitrogen (N) synthesis in beef cows. Forty-four multiparous Nellore cows, comprising 32 gestating and 12 non-gestating cows, with an average weight of 451 ± 10 kg, were assigned to either a HIGH (ad libitum) or LOW (limited feeding at 1.2 times maintenance based on the NRC) feeding regimen during the gestational period. The dry matter intake (DMI) in kg/d was significantly greater (P < 0.01) in HIGH-fed cows. The DMI reduced (P < 0.05) in proportion to the shrunk body weight (SBW) as days of pregnancy (DOP) increased. The interaction between feeding level and DOP was significant (P < 0.05) for the digestibility of dry matter (DM), organic matter (OM), N compounds, ether extract (EE), ash- and protein-free neutral detergent fiber (NDFap), gross energy (GE), and total digestible nutrients (TDN). Except for DM and TDN digestibility, there was a reduced nutrient digestibility as gestation progressed in HIGH-fed cows. In contrast, digestibility increased as a function of DOP in LOW-fed cows. Microbial N synthesis (g/day) was significantly higher in HIGH-fed cows (P < 0.001) compared to LOW-fed cows. The efficiency of microbial N production per g of N intake and kg of digestible OM intake was (P = 0.021) and tended (P = 0.051) to be greater in LOW-fed cows compared to HIGH-fed cows. In summary, HIGH-fed Nellore cows reduce feed intake and digestibility with advancing gestation, affecting feed utilization. In addition, LOW-fed cows, showed higher microbial protein synthesis efficiency, potentially making them more nutrient-efficient under challenging nutritional conditions.
(© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)
Databáze: MEDLINE
Externí odkaz: