Feedlot pens with greenhouse roofs improve beef cattle performance in temperate weather.

Muddy pens can negatively affect welfare and performance of feedlot beef cattle. In some regions with temperate weather, plastic greenhouse covers, above the entire pens are used to fatten cattle in a clean and dry environment. The objective of this research was to investigate effects of greenhouse roofed pens on beef cattle feedlot performance in temperate weather. Data were collected from a feedlot located in Central Mexico between 2016 and 2019. The study included 1,062 closeouts of pens with 68,305 crossbred bulls fed in pens with or without a greenhouse roof. Feeding ranged from 82 to 210 d, depending on the initial weight of cattle, which ranged from 255 to 511 kg. For each pen, average daily dry matter intake (DMI; kg of DMI·animal -1 ·d -1 ), average daily gain (ADG, kg·animal -1 ·d -1 ), and feed efficiency (G:F, ADG/DMI) were measured. Factorial analyses were performed to test the interaction and main effects of initial weight grouping (light, medium, and heavy), roof, and season as fixed effects, and year as a random effect. None of the three-way interactions were significant ( P > 0.51). There was no initial weight grouping × roof interactions for DMI and ADG ( P > 0.31). There was ( P = 0.03) an initial weight grouping × roof interaction for G:F, as pens of all initial weight groups had greater ( P < 0.01) G:F in pens with greenhouse roof than its counterpart in pens without greenhouse roof, but the advantage was greater for pens with light cattle (0.178 vs. 0.166; P < 0.01). There was no initial weight grouping × season interactions for all variables ( P > 0.39). There was no roof × season interaction for DMI ( P = 0.47), but there were interactions for ADG and G:F ( P < 0.01). The ADG was not different ( P > 0.13) during summer and autumn based on the roofing system, but pens with greenhouse roofs had greater ADG during spring (1.70 vs. 1.61) and winter (1.68 vs. 1.64; P ≤ 0.01). The G:F was greater ( P < 0.01) in all seasons for pens with a greenhouse roof, with the most prominent advantage during spring (0.173 vs. 0.160). There were main effects for cattle initial weight grouping and roof for all variables ( P < 0.01). Season affected DMI and G:F ( P < 0.01). Pens with greenhouse roofs had decreased DMI (9.70 vs. 9.86), greater ADG (1.67 vs. 1.63), and increased G:F (0.173 vs. 0.166) compared to pens without greenhouse roofs ( P < 0.01). Pens with greenhouse roofs in feedlots located in temperate regions positively affect beef cattle performance.