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Does virginiamycin supplementation affect the metabolism and performance of Nellore bulls grazing under low and high gain rates?
Author(s) -
Costa João Paulo R.,
De Jesus Raphael B.,
Oliveira Ivanna M.,
Resende Flávio D.,
Siqueira Gustavo R.,
Malheiros Euclides B.
Publication year - 2018
Publication title -
animal science journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.606
H-Index - 38
eISSN - 1740-0929
pISSN - 1344-3941
DOI - 10.1111/asj.13052
Subject(s) - virginiamycin , zoology , pasture , weight gain , biology , randomized block design , grazing , latin square , chemistry , endocrinology , rumen , body weight , agronomy , biochemistry , fermentation , antibiotics
Abstract This study aimed to evaluate the effect of virginiamycin on the metabolism and performance of growing Nellore bulls under low and high gain rates on pasture. In experiment 1, 80 Nellore bulls (age = 12 ± 2 months, body weight = 258 ± 15 kg) were assigned to 16 paddocks in a 2 × 2 randomized block factorial arrangement. In experiment 2, 12 cannulated Nellore bulls were assigned to three 4 × 4 balanced Latin squares. The factors were: (1) mineral salt without or with virginiamycin, and (2) low or high gain rate. No interaction was noted between factors ( p > .10). Animals fed virginiamycin had greater average daily gain (14%, p < .01), body weight (11 kg, p = .05), plasma nonesterified fatty acid (20%, p < .01), serum calcium concentration (2.62%, p = .04), and total protozoa ( p = .03) and had the same bacterial proportion ( p > .27). Animals with a low gain rate had greater serum urea concentration (19.6%, p < .01) and ruminal ammonia nitrogen (62%, p < .01). Thus, virginiamycin increases the performance and changes the metabolism of growing Nellore bulls under low and high gain rates on pasture.