Poster Presentations

Abstract

Introduction Scientific community is continuously searching new feed additives that could prevent digestive disturbances in ruminants as well as are safe to humans who will consume the animal products. The concept of immunity as a potential tool in the manipulation of ruminal fermentation has been previously cited (Berghman and Waghela, 2004). In this scenery, the objective of this trial was to evaluate the effects of two forms (liquid or powder) of polyclonal antibodies preparation (PAP) against specific rumen bacteria Streptococcus bovis, Fusobacterium necrophorum and Lactobacillus on rumen fermentation parameters in ruminally cannulated cows adapted or not to highly fermentable carbohydrates diets (HFC) after an acidosis challenge. Materials and methodsThe present study was carried out at College of Veterinary Medicine and Animal Science (FMVZ/USP), Brazil. Six ruminally fistulated cows were used in this trial. Experimental design was two Latin squares 3x3 in factorial arrangement of treatments 3x2 regarding two feed additives (PAP in powder form (PAPP) and PAP in liquid form (PAPL)) plus control group (CON) and two managements of diets adaptation resulting in six treatments. The first Latin square had a step-up diet adaptation: from D0 to D4 (100% of forage); D5 to D9 (30% of concentrates) and D10 to D14 (60% of concentrates). The second Latin square received 100% of forage from D0 to D14. On D15 and D16, all animals received 80% of concentrates in diet. For pH and total concentration of short-chain fatty acids (tSCFA) analysis, rumen fluid was sampled at 0 and every 3 h postfeeding totaling 36 h (D15 and D16) of challenge with a diet of 80% of concentrates. Short-chain fatty acids included acetate, propionate and butyrate. Data were analyzed by MIXED procedure with a significance level of 0.05. In the model, the effects of treatments and time were considered fixed factors. Period and animal nested in square were considered random factors.Results An interaction between adaptation and time was observed for ruminal pH (P < 0.0001). The adapted group had lower pH values than non-adapted group until 12 h after the start of challenge (6.18 vs 6.55, respectively). For tSCFA concentration, an interaction between adaptation and time was also observed (P < 0.0001). From 0 to 9 h (109.38 vs 82.26 mM) and at 36 h (121.11 vs 107.62 mM) after the start of challenge, the adapted group had greater values compared to nonadapted group. At 24h and 27h, the non-adapted group had greater values compared to the adapted group (114.75 vs 127.4 mM). Polyclonal antibodies preparation, in both forms, did not affect these variables. Conclusions From these data, it is possible to conclude that step-up adaptation did not prevent the drop of rumen pH in conditions of great availability of highly fermentable carbohydrates. High total SCFA concentration is expected in adapted group due to the adaptation of rumen microbial population to the substrate, increasing their fermentative capacity. Both forms of PAP (liquid or powder) did not affec...

Greenhouse gas balance and carbon footprint of beef cattle in three contrasting pasture-management systems in Brazil

“…These pastures are generally low in nutritive quality and typified with relatively high enteric CH 4 emissions per unit weight of dry matter consumed by cattle (Berndt and Tomkins, 2013). Several strategies have been suggested for mitigating enteric CH 4 emissions from pasture-based beef production systems in Brazil, which include increasing the nutritive quality and digestibility of pasture through improved management practices, such as fertilizer and lime application and rotational grazing (Demarchi et al, 2003;Mandarino et al, 2014), and nutritional strategies such as providing grains and protein supplements (De Oliveira et al, 2007;Balieiro Neto et al, 2009b;Berchielli et al, 2011). Presenting measurement and mitigation options of CH 4 emissions from beef cattle in tropical grazing systems from Australia and Brazil, Berndt and Tomkins (2013) showed values that ranged from 21.5 to 65.3 kg CH 4 head À1 yr À1 (varying feed supplements).…”