Acidosis in cattle: a review.

Abstract

Acute and chronic acidosis, conditions that follow ingestion of excessive amounts of readily fermented carbohydrate, are prominent production problems for ruminants fed diets rich in concentrate. Often occurring during adaptation to concentrate-rich diets in feedyards, chronic acidosis may continue during the feeding period. With acute acidosis, ruminal acidity and osmolality increase markedly as acids and glucose accumulate; these can damage the ruminal and intestinal wall, decrease blood pH, and cause dehydration that proves fatal. Laminitis, polioencephalomalacia, and liver abscesses often accompany acidosis. Even after animals recover from a bout of acidosis, nutrient absorption may be retarded. With chronic acidosis, feed intake typically is reduced but variable, and performance is depressed, probably due to hypertonicity of digesta. Acidosis control measures include feed additives that inhibit microbial strains that produce lactate, that stimulate activity of lactate-using bacteria or starch-engulfing ruminal protozoa, and that reduce meal size. Inoculation with microbial strains capable of preventing glucose or lactate accumulation or metabolizing lactate at a low pH should help prevent acidosis. Feeding higher amounts of dietary roughage, processing grains less thoroughly, and limiting the quantity of feed should reduce the incidence of acidosis, but these practices often depress performance and economic efficiency. Continued research concerning grain processing, dietary cation-anion balance, narrow-spectrum antibiotics, glucose or lactate utilizing microbes, and feeding management (limit or program feeding) should yield new methods for reducing the incidence of acute and chronic acidosis.

Increasing sodium bicarbonate level in high-concentrate diets for heifers. II. Effects on chewing and feeding behaviors

“…For example, ruminating time decreased linearly in a period of time when ruminal pH reached the nadir, from 12 to 14 h. Rumination is necessary during this time to increase saliva production, which buffers the rumen (Bailey and Balch, 1961). Meal size increased linearly during the 4 h following feeding, which may negatively affect ruminal pH and its post-prandial drop, as suggested by Allen (1997), Owens et al (1998), andCooper et al (1999). However, there is little doubt about the buffering effect of bicarbonate in the rumen (Kohn and Dunlap, 1998), which was supported in the present study by the finding that despite increasing buffer level, increased meal size during the 4 h post-feeding and drop in pH was attenuated (Gonzá lez et al, 2008).…”

“…High proportion of concentrates in the ruminant's diets may result in physiological disorders such as ruminal acidosis, which was related to anorexia, liver abscesses, poor performance, diarrhea and lethargy (Owens et al, 1998). Ruminal buffers such as sodium bicarbonate (BICARB) have traditionally been used to improve performance and rumen health of beef cattle on these diets.…”

“…However, other management factors may alter the eating patterns and become the cause of low ruminal pH, e.g. factors that increase meal size and eating rate may result in lower ruminal pH and greater risk of acidosis (Allen, 1997;Owens et al, 1998;Schwartzkopf-Genswein et al, 2003). Feeding BICARB increased ruminal pH and osmolality (Rogers and Davis, 1982).…”

Rumen chemical and bacterial changes during stepwise adaptation to a high-concentrate diet in goats

“…However, after feeding diet IV, ruminal pH decreased to 5.3 on day 2 and it was maintained at about 4.7 on day 3. At the same time, goats started to reduce their feed intake on day 2 and refused to take any feed on day 3, indicating the occurrence of metabolic acidosis (Owens et al, 1998;Gentile et al, 2004). Ruminal lactic acid concentration was stable and maintained in a range of 2.71 to 3.63 mmol/l during the initial three feeding periods, but increased significantly 1 day after feeding diet IV, with a peak of 10.6 mmol/l on day 2 of feeding diet IV and then decreased (Table 2).…”

The effect of dietary water soluble carbohydrate to nitrogen ratio on nitrogen partitioning and isotopic fractionation of lactating goats offered a high-nitrogen diet

“…In addition, evidence obtained from an in vitro study in which increased WSC concentration in fresh forages were obtained by harvesting at different time of the day suggests that there may be a concentration of WSC (~24%) that optimises rumen fermentation processes (Burke et al, 2011). Owens et al (1998) suggested that the synthesis of microbial protein in the rumen may also be reduced by acidosis from feeding high level of WSC. This is partly evident from the low PD for medium high and high treatments in period 1.…”