Resumo
ABSTRACT The objective of this study was to evaluate the effect of either a limited forage intake or concentrate supplementation prior to the adaptation to high-concentrate diets on dry matter intake, ruminal pH, bacteria, and protozoa of Nellore cattle. The experiment was designed as a two 3×3 Latin square, and six cannulated Nellore steers were used. Each experimental period was composed by three feeding phases: pre-adaptation (14 days), adaptation (12 days), and finishing (seven days) diet, in a total of 33 days per period. The steers were assigned to one of three pre-adaptation dietary treatments: control (Tifton hay fed ad libitum + mineral supplement), restriction (Tifton hay fed at 1.4% of BW + mineral supplement), and concentrate (Tifton hay fed ad libitum + 0.5% of BW of a mix of concentrate feedstuffs and mineral supplement). The adaptation period consisted of two adaptation diets, which contained 72 and 79% concentrate for six days each. The finishing diet contained 86% concentrate. During the pre-adaptation phase, restricted cattle had higher pH than concentrate-fed cattle. There was a reduction in M. elsdenii relative population in cattle from either restriction or concentrate groups. During adaptation and finishing phases, cattle from concentrate group had smaller F. succinogenes populations compared with the control group. The previous nutritional backgrounds impact ruminal microbiota during adaptation and finishing phases without causing any negative effect on ruminal pH. Feeding concentrate prior to the adaptation positively impacted the transition to high-concentrate diets and promoted increased dry matter intake.
Resumo
This survey aimed to provide a current outlook of nutritional recommendations and management practices adopted by feedlot nutritionists in Brazil. The survey questionnaire consisted of 96 questions that included general information on nutritionists, animals, ingredients utilized in finishing diets, management and formulation practices, feeding management, and challenges associated with applying nutritional recommendations in practice. Thirty-six nutritionists, responsible for 4,671,062 animals in Brazil, responded our questionnaire. An increase in the percentage of nutritionists (38.9%) recommending 66% or more grain inclusion in the diets was observed. Fine grinding remained the preferred grain processing method by nutritionists (44.4%); however, more than 50% of nutritionists recommended high-moisture harvest and storage as the secondary grain processing method of choice. The average level of concentrate in the diets was 83.3%, which is higher compared with past surveys. The preferred fiber analysis method by 80.6% respondents was physically effective neutral detergent fiber (peNDF), and corn silage remained the main roughage source in finishing diets (69.4%). Improvements in diet mixing and distribution were also noted. While 79.0% of nutritionists' clients use a truck-mounted mixer and 69.5% of them also use programmed delivery per pen, 44.4% of the nutritionists reported that their clients use clean-bunk management. Respiratory diseases and acidosis (reported by 71.4 and 27.6% of the respondents, respectively) are among the main health problems. The present survey provides an overview of nutritional practices currently adopted by feedlot nutritionists, who played an important role on the improvement of feeding management in Brazil over the last 10 years.