Resumen:
One of the major challenges facing the animal production
industry in developing countries is to
improve efficiency of production and to maintain
feed utilization. Many attempts have been made by
researchers to overcome these challenges, such as including
the incorporation of antimicrobials and other
natural products into animal feeds (Ahmed et al.
2015; Rojo et al. 2015; Morsy et al. 2016). Feed additives
of microbial origin, ionophores and antibiotics
have become a common practice in ruminant nutrition;
however, most studies have been conducted
with lactating cows or in vitro, with few studies on
pre-weaned calves.
Descripción:
Sampling and analysis of rumen fluid
As described in Kholif et al. (2015), on the last day of
the experiment (i.e. day 90), ruminal contents were
sampled at 0, 3 and 6 h post-morning feeding to
determine the pH and concentration of fermentation
end-products. About 100 ml of rumen content was
collected once at each sampling time from the
ventral sac by using a stomach tube, and then the
sample taken from each calf was strained through
four layers of cheesecloth. The pH of ruminal fluid
was measured immediately after collection using a
pH meter (Orion™ Star A211 pH Benchtop Meter,
Thermo Scientific, Beverly, MA, USA).