Repeated ruminal acidosis challenges in lactating dairy cows at high and low risk for developing acidosis: Feeding, ruminating, and lying behavior
ABSTRACT An experiment was conducted to determine whether the susceptibility to ruminal acidosis, as defined through differences in days in milk (DIM), milk production level, and ration composition, influences cow feeding, ruminating, and lying behavior and whether these behaviors change during an acute bout of ruminal acidosis. Eight ruminally cannulated cows were assigned to 1 of 2 acidosis risk levels: low risk (LR, mid-lactation cows fed a 60:40 forage:concentrate ratio diet) or high risk (HR, early lactation cows fed a 45:55 forage:concentrate diet). As a result, diets were intentionally confounded with DIM and milk production to represent 2 different acidosis risk scenarios. Cows were exposed to an acidosis challenge in each of three 14-d periods. Each period consisted of 3 baseline days, a feed restriction day (restricting total mixed ration to 50% of ad libitum intake), an acidosis challenge day (1 h meal of 4 kg of ground barley/wheat before allocating the total mixed ration), and a recovery phase. Feeding, rumination, and standing/lying behavior were recorded for 2 baseline days, on the challenge day, and 1 and 4 d after the challenge day for each cow. Across the study, there were no differences in measures of standing, lying, or feeding behavior between the 2 groups of cows. The HR cows did, on average, spend less time ruminating (491 vs. 555 min/d) than the LR cows, resulting in a lesser percentage of observed cows ruminating across the day (44.6 vs. 48.1%). The acidosis challenge resulted in changes in behavior in all cows. Compared with the baseline, feeding time increased on the first day after the challenge (395 vs. 310 min/d), whereas lying time decreased (565 vs. 634 min/d). Rumination time decreased the first day following the challenge (436 min/d) relative to the baseline (533 min/d), but increased the following day (572 min/d). Fewer cows were observed to be ruminating at a given time on the first day following the challenge as compared with the baseline period. Despite this, on a herd level, numerous observations of the proportion of cows ruminating at any one time would need to be taken to accurately detect an acute bout of acidosis using changes in rumination behavior. Overall, these results suggest that risk of acidosis may have little overall effect on general behavior, with the exception of rumination. Furthermore, an acute bout of acidosis alters behavioral patterns of lactating dairy cows, particularly rumination behavior, and identification of these changes in behavior through repeated measurements may assist in the detection of an acidosis event within a herd.
- Journal of Animal Science 01/2015; DOI:10.2527/jas.2014-8802 · 1.92 Impact Factor
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ABSTRACT: Li, S., Gozho, G. N., Gakhar, N., Khafipour, E., Krause, D. O. and Plaizier, J. C. 2012. Evaluation of diagnostic measures for subacute ruminal acidosis in dairy cows. Can J. Anim. Sci. 92: 353-364. Effects of subacute ruminal acidosis (SARA) challenges on measurements of feces, urine, milk and blood samples, and of feeding behavior were investigated to determine which of these measurements may aid in the diagnosis of SARA. Eight multiparous lactating dairy cows were used in a crossover design with two 6-wk experimental periods. During weeks 1,2, and 6, cows received a control diet with a forage-to-concentrate ratio of 58:42. During weeks 3 to wk 5, a grain-based SARA challenge (GBSC) or an alfalfa-pellet SARA challenge (APSC) was conducted by replacing 12% of the dry matter of the control ration with pellets containing 50% ground wheat and 50% ground barley, and by replacing 26% of the dry matter of the control ration with pellets of ground alfalfa, respectively. The rumen pH depression did not differ between the challenges. The GBSC increased the concentrations of lipopolysaccharide (LPS) in feces and of serum amyloid A in blood, but decreased that of milk fat and urea in blood. The APSC increased the urine pH, the net-acid-base excretion, and the red blood cell count and potassium concentration in blood. Both challenges increased the concentrations of LPS and propionate in rumen fluid, protein in milk, glucose, lactate and sodium and the partial pressure of CO2 in blood, and tended to decrease the concentration of chloride in blood. The measures that were similarly affected by both challenges may aid in the diagnosis of a rumen pH depression. Differences between the SARA challenges suggest that this disorder is not solely rumen pH dependent.Canadian Journal of Animal Science 09/2012; 92(3):353-364. DOI:10.4141/cjas2012-004 · 0.98 Impact Factor
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ABSTRACT: Subacute Ruminal Acidosis (SARA) corresponds to an imbalance between lactate-producing bacteria and lactate-using bacteria, which results in a change in ruminal pH associated with a prevalent consumption of rapidly fermentable carbohydrates. In our study, 216 primiparus and multiparus dairy cows were selected from 20 Italian intensive dairy herds and were divided into three groups based on the risk of SARA. All the dairy cows had high average milk production. After blood sampling, a complete blood gas analysis was performed. One-way ANOVA was performed to compare the three groups. O(2) Cont, PCO(2), blood pH, O(2)Hb, urinary pH, and rumen pH were significantly lower in cows with rumen pH < 5.5. These results indicate that blood gas analysis is a valuable tool to diagnose acidosis in dairy cows because it provides good assessment of acidosis while being less invasive than rumen pH analysis.09/2010; 2010. DOI:10.4061/2010/392371