The influence of Megasphaera elsdenii on rumen morphometrics of cull cows immediately stepped up to a high-energy finishing diet

• Published in: Translational animal science 2020-01, Vol.4 (1), p.194-205
• Main Authors: DeClerck, Jonathan C, Reeves, Nathan R, Miller, Mark F, Johnson, Bradley J, Ducharme, Gary A, Rathmann, Ryan J
• Format: Article
• Language: English
• Subjects: Ruminant Nutrition
• ISSN: 2573-2102; 2573-2102
• DOI: 10.1093/tas/txz185

Forty-five beef cull cows [body weight ( ) = 503 ± 58 kg; body condition score ( ) = 2.1 ± 0.6] were randomized into two treatments to compare the effects of oral drenching of no probiotic vs. 100 mL of NCIMB 41125 ( ; Lactipro Advance; 2 × 10 cfu/mL; MS Biotec, Inc., Wamego, KS) on the realimentation of cull cows. The study featured a rapid 0-d step-up of concentrate-naïve cull cows to a 90% concentrate diet (1.43 Mcal/kg of NE ). The cows were finished for 35 d and were fitted with a wireless rumination tag (Allflex Flex Tag; SCR Engineers, Ltd, Netanya, Israel), which tracked head movement to record eating and chewing activity. Rumen morphometrics was recorded on the harvest floor, with each carcass assigned a rumenitis score, and a fragment of the cranial sac removed for further papillae analysis. An additional 23, thin, non-fed cull cows were harvested at the same abattoir to compare the effects of concentrate realimentation on ruminal morphometrics. culture-drenched cattle registered a 13.3% increase in rumination time (39.27 min/d, 0.03) during the first week of the trial compared to controls. A numerical rumination advantage for culture administered cattle was observed during week 2 of trial ( 0.17), with no differences between treatments from weeks 3 to 5 ( 0.40). Subjective rumenitis evaluations approached a tendency ( 0.12), with non- culture-drenched concentrate-fed cattle logging twice the score of their day 0 cohorts (2.52 vs. 1.17) suggesting considerable lactic insults occurred to the ruminal epithelium in the short 35-d trial. Despite the short feeding duration, concentrate realimentation prompted a significant improvement in mean papillae area ( 0.01). Among concentrate-fed treatments, culture-drenched cattle posted superior absorptive surface area ( 0.01) and a greater ratio of papillae area of absorptive surface area ( 0.05), suggesting that culture is favorably altering the ecology of the rumen and promoting papillae growth perhaps by mitigating lactate-driven pH drops. In conclusion, culture application in a 0-d step-up protocol to finishing diets can help mitigate the effects of ruminal acidosis.