Characterization of Oligofructose-Induced Acute Rumen Lactic Acidosis and the Appearance of Laminitis in Zebu Cattle

SIMPLE SUMMARY: In this paper we characterize oligofructose-induced acute rumen lactic acidosis in zebu cattle focusing on alterations of the experimental protocol concerning ruminal condition. Here we describe zebu cattle’s lack of adaptation to the oligofructose induction model for laminitis and we provide methodology of adaptation that allows the higher occurrence of laminitis with a lower degree of ruminal acidosis and better animal welfare. Additionally, we compare the animals that required and did not required supportive treatment, to try to understand which factors are related to susceptibility. The induction model promoted marked reduction in rumen pH, rumen anaerobiosis, carbon dioxide pressure, and an increase in rumen lactate, blood osmolarity, and cortisol concentration. The animals treated had lower values of rumen pH and marked dehydration, evidenced by the increase in globular volume and serum urea. The clinical condition caused by excess oligofructose is more severe than the classical sucrose induction model, but is efficient in producing laminitis. ABSTRACT: The objective of this study was to characterize oligofructose-induced acute rumen lactic acidosis and its consequences in zebu cattle. We used 29 Nellore heifers which were submitted to experimental induction of laminitis by oligofructose excess. During the induction period, the animals underwent clinical examination, including laminitis diagnosis (hoof pressure testing and locomotion score) and blood and ruminal fluid sampling every six hours (over the initial 24 h) and every 12 h (up to 72 h), after the highest dose. Almost half of the animals (48.1%) required treatment with bicarbonate and saline to correct metabolic acidosis and dehydration. Due to this treatment, the animals were analyzed in treated (n = 13) and non-treated (n = 14) groups. The induction model promoted marked reduction in rumen pH, rumen anaerobiosis, carbon dioxide pressure, and increase in rumen lactate, blood osmolarity, and cortisol concentration. The animals treated had lower values of rumen pH and marked dehydration, evidenced by the increase in globular volume and serum urea. The clinical condition caused by excess oligofructose is severe, with the differential of the appearance of ephemeral fever and respiratory compensation against systemic acidosis, in addition to the frequent appearance of laminitis.