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Evaluation of corn processing and lasalocid in Nellore cattle finished on high supplementation system during the dry season

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Paloma Helena Gonçalves
Total Authors: 1
Document type: Master's Dissertation
Press: Jaboticabal. 2018-10-29.
Institution: Universidade Estadual Paulista (Unesp). Faculdade de Ciências Agrárias e Veterinárias. Jaboticabal
Defense date:
Advisor: Gustavo Rezende Siqueira

The objective of this study was to evaluate the effects of corn processing and the inclusion of lasalocid sodium on Nellore beef cattle finished in a high supplementation system, in the dry season, on performance, carcass characteristics and rumen parameters. In Experiment 1, 12 castrated Nellore cattle with mean body weight (BW) of 524±41,1 and approximately 36 months of age were used, fistulated in the rumen for evaluation of ruminal parameters, distributed in three 4 × 4 Latin squares, using the initial weight as the blocking criterion. The treatments consisted of a 2 x 2 factorial factorial arrangement. Factor 1: type of corn processing (milled dry corn (MDC) or high moisture corn (HMC) and factor 2: the use or not of additive (without inclusion (WLS) or with inclusion (ILS) of lasalocid sodium at a dose of 32 mg/kg of dry matter of the concentrate). The animals were supplemented ad libitum, with 60% corn inclusion in the concentrate. The experimental period was from October 2016 to January 2017, divided into four periods of 21 days, totaling 84 experimental days. Ruminal liquid harvests were carried out on the 19th day of the period to measure pH, ammoniacal nitrogen (N-NH3) and short-chain fatty acids (SCFA). In the experiment 2, sixty-eight Nellore bulls (371±12,3 kg of BW and 25 months of age) were used. From this total, four were slaughtered at the begin of the experiment (reference group) to estimate the initial carcass characteristics. The treatments were in a randomized block design in a 2 × 2 factorial arrangement, described above. The experimental period was 112 days (four periods of 28 days), average daily gain (ADG) and forage evaluations were performed every 28 days and evaluation of the carcass composition. The experimental unit was the paddock, the randomized block design, 2 × 2 factorial arrangement. Data were analyzed using a mixed model using the MIXED procedure of the SAS. Significance was declared with P<0.05, by the t test, with a trend discussed when 0.05<P<0.10. There was an effect on the type of corn processing in the acetate: propionate ratio (P <0.01). The acetate:propionate ratio was 18.7% lower in animals supplemented with HMC. For the pH there was interaction between the processing, the additive inclusion and the collection times after the supplementation (P=0.03). At time 0, the animals supplemented with HMC+WLS and HMC+ILS presented pH 6.6% higher than animals supplemented with MDC+WLS and MDC+ILS. Six hours after supplementation, animals HMC+WLS, MDC+WLS and MDC+ILS presented pH 4.5% lower when compared to animals supplemented with HMC+ILS. Twelve hours after supplementation, animals supplemented with MDC+ILS presented higher pH, being 2% higher when compared to those receiving MDC+WLS and 7.1% higher than the animals that received HMC+WLS and HMC+ILS. On the other hand, animals supplemented with MDC+WLS presented a pH of 5% higher than those supplemented with HMC+WLS and HMC+ILS, which did not differ among them. There was a tendency (P=0.06) of interaction between the factors and the periods for the BW of the animals. In the third period, animals supplemented with HMC+ILS presented 17 kg of PC more than the other treatments. At the end of the experiment, animals supplemented with HMC+ILS presented 9 kg more BW relative to HMC+WLS, and 21 kg more than those who received MDC+ILS. In this same period there was no difference for the animals supplemented with MDC+WLS compared to the animals supplemented with HMC+WLS and MDC+ILS. Also, animals supplemented with HMC+WLS obtained 12 kg of BW more than those supplemented with MDC+ILS. The animals that consumed MDC presented 8.1% higher DMI than the animals that consumed HMC. On the other hand, the animals that consumed HMC obtained 0.120 kg of general ADG, reflecting in higher feed efficiency compared to those who consumed MDC, being 20% more efficient to convert the diet consumed to gain. For the final hot carcass weight, there was a tendency for the interaction between the factors (P=0.09), animals supplemented with HMC+ILS presented 11 kg over carcass when compared to the other treatments. It was concluded that animals consuming HMC presented lower acetate:propionate ratio. The intake of HMC+WLS promoted higher body weight and carcass weight in Nelore cattle finishing in dry pasture. Animals supplemented with HMC have lower DMI and better feed efficiency. (AU)

FAPESP's process: 17/03395-7 - Evaluation of corn processing and lasalocid Nellore cattle finishing in high dry supplementation system
Grantee:Paloma Helena Gonçalves
Support Opportunities: Scholarships in Brazil - Master