Abstract

The effects of eight different pre-slaughter diets on gut microflora, pH and dry matter were evaluated in 112 slaughter-weight, pasture-finished heifers. Hide dirtiness at slaughter, plasma cortisol, meat pH and stickiness, and liveweight loss, were also examined. The pre-slaughter diets were: 48 h of 100% meadow hay, lucerne hay, red clover hay, perennial ryegrass hay, haylage, haylage supplemented with maize silage, pasture, or 24 h fasting before transport. Fasted animals had the highest counts of rumen Escherichia coli and Enterobacteria compared to other treatments ( P<0.001), while red clover hay and haylage had the lowest ( P<0.05). Faecal E. coli counts were also highest for fasted animals ( P<0.05). Rumen E. coli and Enterobacteria counts were positively correlated with rumen pH ( P<0.001), and negatively correlated with fibre intake ( P<0.001). Diet significantly affected the pH of both the rumen and faeces ( P<0.001), with fasted animals having the highest rumen pH and haylage and red-clover hay-fed animals the lowest. Dry matter (%) of the rumen contents was also significantly affected by diet ( P<0.001). The mean carcass weight of fed heifers was 5 kg heavier than that of the fasted heifers ( P<0.05). A pH/volatile fatty acid (VFA) dependent mechanism is suggested as the major mode for E. coli suppression by feeds used in the study. Coumarins may have contributed to lower ruminal and faecal E. coli counts with E. coli counts negatively correlated with expected coumarin ingestion ( P<0.01). Feeding pasture-fed cattle conserved herbaceous forages, in preference to fasting, before transport for slaughter may prove beneficial in reducing the risk of carcass contamination with E. coli and other bacteria of digesta and/or faecal origin, and in protecting carcass weight.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.