Ruminal acidosis and the rapid onset of ruminal parakeratosis in a mature dairy cow: a case report

Michael A Steele,Ousama AlZahal,Brian W McBride,Jim Croom,Sarah E Hook

doi:10.1186/1751-0147-51-39

Michael A Steele, Ousama AlZahal + Show 3 more

Open Access

https://doi.org/10.1186/1751-0147-51-39

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Abstract

A mature dairy cow was transitioned from a high forage (100% forage) to a high-grain (79% grain) diet over seven days. Continuous ruminal pH recordings were utilized to diagnose the severity of ruminal acidosis. Additionally, blood and rumen papillae biopsies were collected to describe the structural and functional adaptations of the rumen epithelium. On the final day of the grain challenge, the daily mean ruminal pH was 5.41 ± 0.09 with a minimum of 4.89 and a maximum of 6.31. Ruminal pH was under 5.0 for 130 minutes (2.17 hours) which is characterized as the acute form of ruminal acidosis in cattle. The grain challenge increased blood beta-hydroxybutyrate by 1.8 times and rumen papillae mRNA expression of 3-hydroxy-3-methylglutaryl-coenzyme A synthase by 1.6 times. Ultrastructural and histological adaptations of the rumen epithelium were imaged by scanning electron and light microscopy. Rumen papillae from the high grain diet displayed extensive sloughing of the stratum corneum and compromised cell adhesion as large gaps were apparent between cells throughout the strata. This case report represents a rare documentation of how the rumen epithelium alters its function and structure during the initial stage of acute acidosis.

Highlights

In response to the demands for increased feed conversion, cattle, sheep and goat producers rely on rapidly fermentable diets to maximize energy intake
The rumen mucosa plays a vital role in whole-animal energy balance through the transport and metabolism of rumen-derived volatile fatty acids (VFAs) [3]
The acute form of ruminal acidosis was induced rapidly and the four strata of the rumen epithelium was found to elicit an adaptive response to the acidic rumen environment

Summary

Background

In response to the demands for increased feed conversion, cattle, sheep and goat producers rely on rapidly fermentable (high - grain) diets to maximize energy intake. A 10-year old, non-lactating Holstein dairy cow, fitted with a rumen cannula, was nutritionally induced to develop ruminal acidosis by increasing the proportion of grain in the diet. The HG diet fed on day 14 consisted of 3.3 kg of chopped hay, 12.5 kg of mixed grains (40% ground wheat, 40% ground barley, 20% ground corn) and 100 g of supplemental mineral and vitamins (88.9% dry matter, 117 g crude protein/kg dry matter, 240 g neutral detergent fibre/kg dry matter, 580 g non-fibre carbohydrate/kg dry matter, 501 g starch/kg dry matter). Continuous ruminal pH recordings, blood samples and rumen papillae biopsies were collected from the ventral sac on day 7 (HF) and 14 (HG) for assessment. Ruminal pH, blood metabolite and rumen papillae gene expression From days 1 to 14 of the study, the cow consumed all dietary components. Increased infiltration of the upper strata of the ruminal epithelium with lymphocyte-like cells was observed (micrographs not shown)

Discussion

Conclusion

Findings

Baldwin RL VI

13. Hegardt FG