PSLBII-2 - Impact of controlled feeding on enteric methane production and animal performance

Abstract: The impact ruminants have on environmental sustainability has been of growing concern in recent decades. Many cattle in the northern great plains are fed on family-owned farms and feedlots, highlighting the need for producer-friendly mitigation strategies, such as the established, but not widely adopted management strategy of controlled or precision feeding. The objective of this experiment was to determine the impact of precision feeding on enteric methane (CH₄) production and subsequent animal performance. Angus-cross steers (n= 48, BW = 447 ± 4.4kg) were blocked by body weight (BW) and assigned to one of three treatment groups. Treatments consisted of a control (CON) where steers were fed ad-libitum, Treatment 1 (TRT1) 96 percent of ad-libitum and Treatment 2 (TRT2) 92 percent of ad-libitum. TRT1 and TRT2 were adjusted once weekly based on the CON steers average intakes from the previous week. BW was measured on d 0, 1, 28, 56, and 84 and dry matter intake (DMI; kg/d) was measured using an Insentec Roughage Intake Control System (Insentec, Markenesse, The Netherlands). Enteric CH₄ and carbon dioxide (CO₂) production was determined utilizing 2 GreenFeed emission measurement systems (AHCS; C-Lock Inc., Rapid City, SD). Only visits greater than 3 minutes in duration were used for analysis. Average Daily Gain (ADG) and gain to feed (G:F) did not differ among treatments (P =0.17, P = 0.8), but ADG had a tendency to decrease (linear; P = 0.09). DMI was greatest for CON and least for TRT2 (P ≤ 0.01). CH₄ (g/d) output differed between treatments (P ≤ 0.007). There was a tendency for a quadratic relationship for derived methane yield (MY; g/kg dry matter intake (DMI)) among treatments (P = 0.10). Emission intensity (EI; g CH4/kg gain) was not different across treatments (P = 0.40). These results suggest precision feeding may have a positive impact on methane emissions but could negatively impact performance.