Effect of fiber contents and the addition of monensin or functional oil on the performance and methane emission of Nellore finishing cattle

Author(s)

Elaine Magnani

• Document type: Doctoral Thesis
• Press: Pirassununga.
• Institution: Universidade de São Paulo (USP). Faculdade de Zootecnica e Engenharia de Alimentos (FZE/BT)
• Defense date: 2017-08-11

Examining board members

Paulo Roberto Leme; Alexandre Berndt; Roberta Carrilho Canesin; Wignez Henrique; Claudia Cristina Paro de Paz

• Advisor: Paulo Roberto Leme

Abstract

The effect of monensin (MON) or functional oil (FO) and different levels of neutral detergent insoluble fiber from roughage (NDFf) on performance, methane emission, carcass characteristics and meat quality of Nellore finishing cattle were evaluated. For this, two experiments were performed concomitantly, using a total of seventy animals. Experiments 1 and 2 counted on 30 and 60 Nellore bulls, respectively. The initial body weight (BW) was 409 ± 6.36 and 407.4 ± 3.05 kg respectively, and the age was approximately 24 months. The diet was composed of Brachiaria brizantha cv. Marandu, grain corn, soybean meal, ground citrus pulp, urea, potassium chloride, sodium chloride and core confinement. The experimental design was completely randomized with ten animals per treatment, being factorial scheme 3x2 in experiment 2. In experiment 1, the treatments were: control (CTL), which consisted of a base diet, without additives; monensin (MON), base diet with addition of sodium monensin (30mg. kg DM) and functional oil (FO), base diet with addition of functional oil (500mg. kg DM). In the experiment 2, the treatments were: three concentrations of NDF from roughage (6, 9 and 15% of DM) and two additives: functional oil or monensin sodium. The experiments had duration of 105 days and 14 days for adaptation. The analyzes of variance for all the characteristics were performed by the MIXED procedure of the SAS program. In the experiment 1, the animals that received MON presented higher DMI and nutrients NDF, ADF and starch (kg.dia-1), compared to the CTL treatment. The use of FO promoted a decrease in DMI (kg.dia-1) and in percentage of live weight and nutrients, organic matter, ethereal extract, NDF, starch, protein and non-fibrous carbohydrates (kg.d-1), compared to CTL treatment. The use of additives promoted an improvement in the ingestive behavior of the animals, and the animals that received MON had a longer rumination time (259.76 vs 185.7) and efficacy of rumination (29.80 vs 21.48) compared to the treatment CTL. The use of FO increased all the ingestive behavior variables evaluated, compared to CTL treatment (P <0.01). The animals of the CTL treatment were selected against the long diet particles and the animals that received the MON and FO additives in favor of these particles. The use of FO promoted an increase in the digestibility of NDF compared to the CTL treatment, being this difference of 21%. The animals fed the MON had a lower mean daily pH value compared to the CTL treatment animals, thus, as a longer time with pH below 5.6 in h / d, with a mean of 72.4% higher than the time of the CTL treatment below this value. The supply of MON caused an anti-protozoal effect, decreasing the Entodinium genus by 24% and the genus Epidinium by 78%. The use of FO, in turn, decreased the genus Epidinium by 78%, compared to the CTL treatment. The CTL treatment animals presented higher methane emission (g.d), compared to the FO, with a difference of 15.5% in this emission. The use of both additives did not promote differences in productive performance variables compared to CTL treatment. The CTL treatment animals had lower liver and empty gastrointestinal tract weights, compared to the use of MON, in addition to a greater carcass depth (P = 0.06) compared to the FO use. The additives did not differ from the CTL treatment in terms of warm carcass weight, carcass yield and gain yield. In experiment 2, the interaction between NDFf and the additives was significant for the intake of DM, with the highest intake observed in the treatment with inclusion of 15% of NDFf and use of MON. There was a quadratic effect of the levels of NDFf for the intake of ethereal extract and starch, being the highest values obtained with inclusion of 9% of NDFf. There was also a quadratic effect of NDF levels for non-fibrous carbohydrate intake, with levels with inclusion of 9% and 15% of NDF greater than the treatment with inclusion of 6% NDF. As well as, quadratic effect for total digestible nutrients and metabolizable energy intake, with higher values with inclusion of 15% of NDF. The intake of NDF as a percentage of live weight, as well as ADF intake in kilograms per day, had a linear effect with the inclusion of NDF levels, with higher values with inclusion of NDF of 15%. The interaction between the use of the additives and the levels of NDF was significant for rumination time. As well as for rumination efficiency. The use of MON showed less feeding time (FT), chewing time (CWT) and feeding efficiency, compared to treatment with FO. The FT and CWT increased linearly as a function of the increase in NDF levels, with no difference (P> 0.10) between the treatments with inclusion of 6% and 9% of NDF. It was observed an increase in the digestibility coefficient of the NDF with the use of the FO compared to the use of MON. The animals feed MON remained longer consecutively with pH between 5.5 and 5.6 than the animals that received OF diets, as well as treatment with inclusion of 6% of NDFf. The use of FO provided a 45% increase in the total population of ciliate protozoa of the rumen. The treatment with inclusion of 15% of NDF showed a higher protozoa of the genus Metadinium, however, the total number of protozoa was higher with the inclusion of 9% of NDF. The average methane emission (g.d) of the treatment using FO was lower than the average of the treatment with MON, with 14% being methane emission (g.kg MS) and emission of methane as a percentage of gross energy intake was lower with MON use. The increase in the inclusion of NDF levels caused an increasing linear effect on the emission of methane (g.d) and CH4 / ADG (g.kg), and the increase of 1% of NDF in the diet provided an increase of 6.7% in the emission of CH4 (g.d). The use of MON promoted a 5% increase in final live weight and empty live weight, compared to the use of FO, with a 15% increase in ADG, however, without any difference in feed efficiency. The animals of the MON treatment presented higher subcutaneous fat thickness, warm carcass weight, renal, pelvic and inguinal fat, liver weight and empty gastrointestinal tract weight compared to the animals that received OF as an additive, however, without differing in the yield of carcass and gain yield. There was a linear effect increasing with the inclusion of NDFf levels in the weight of the full gastrointestinal tract, being 26% higher at the 15% level of NDFf compared to the level of 6% NDFf. The meat of the animals fed with MON showed higher values for the shear force variables. As for the fatty acid profile, the treatment with FO had a higher value of monounsaturated fatty acids and a lower value for n-3 compared to the use of MON. a linear effect of NDF levels was observed for the succulence variable evaluated in the sensory analysis, the lowest value being observed with the inclusion of 6% NDF, not differing between treatments with inclusion of 9% and 15% NDF. The levels of NDFf promoted quadratic effect in the soft variable, differing among all the treatments, being the lowest value observed with the inclusion of 6% of NDFf. The use of functional oil is indicated in order to improve the digestibility of the fiber and reduction in methane emissions, however, it is not superior to the monensin additive as to the performance of the animals. Diets with low inclusion of roughage, with up to 6% neutral detergent fiber derived from roughage, are recommended for feedlot cattle. (AU)

• FAPESP's process: 13/21695-7 - EFFECT OF ADDITION OF MONENSIN AND OIL FUNCTIONAL ON PERFORMANCE AND EMISSION OF METHANE FROM FINISHING NELLORE BULLS ON DIETS WITH LOW NEUTRAL DETERGENT FIBER OF FORAGE
• Grantee: Elaine Magnani Biazotti
• Support Opportunities: Scholarships in Brazil - Doctorate