Effects of selected feed additives to improve growth and health of dairy calves

• Ano de defesa: 2017
• Autor(a) principal: Londoño Salazar, Luisa Fernanda
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal de Viçosa
• Palavras-chave em Português: Monensin - supplementation - evaluation; Monensi - animal nutrition; Bovine milk- nutrition; Ciências Agrárias; Zootecnia; Avaliação de Alimentos para Animais
• Link de acesso: http://www.locus.ufv.br/handle/123456789/12377

We aimed to evaluate the effect of supplementation with monensin (MON), probiotics or essential oils on performance and fecal consistency index (FCI) of suckling dairy calves from 6-60 d of age, and its residual effect 15 d after weaning. Fifty Holstein calves were fed 5 L of raw milk per day plus starter concentrate until weaning. The treatments were: Control (CON), adition of MON (30 mg/kg of starter), probiotic E. faecium (PROB, 70 mg/kg of starter, CFU/kg 7,0E+09, Cylactin ® ), essential oils (EO, 300 mg/kg of starter, CRINA ® Ruminants), or addition of PROB +EO (EOPROB). DMI and fecal score (scored from 1 to 4) were daily measured, and animals were weighed every 15 d. DNA extraction from feces was performed, to identifying by PCR the presence or absence of microorganisms ( E. coli, Hafnia, Shiguella, Lactobacillus spp, Enterococcus spp, and Enterococcus faecium NCIMB 10415) in the feces. Two 72 h digestibility trials were performed at days 20-28 (period 1) and 50-56 (period 2), by total fecal collection. The experiment was designed in completely randomized block with ten replications per treatment, and date of entrance used as block. ANOVA was performed to test treatment effects at P < 0.10, means were compared by Student's t-test, and PCR results were analyzed by Wald test. The dry matter intake (DMI) before weaning was greater (P < 0.05) for EO (903.03 g / d) compared to MON (794.34 g / d) and EOPROB (783.12 g / d). EO and MON decreased (P < 0.012) FCI during pré-weaning. Average daily gain (ADG) and feed efficiency (FE) did not differ among treatments (P > 0.10) before weaning. The withers height (WH) and croup height (CH) was no different among treatments after or before weaning. After weaning the DMI and FCI did not differ among treatments (P > 0.10). EO had greater (P < 0.05) ADG (917.50 g / d) compared to CON (615.80 g/d) and PROB (592.60 g / d). The FE improved (P < 0.05) with EO (0.72 g / g) over CON (0.36 g / g), MON (0.49 g / g) and PROB (0.36 g / g). The PCR results showed absence of E. faecium NCIMB 10415 in animals fed PROB and CON. During the digestibility trials, greater intakes (P < 0.001) of nutrients were observed at days 50-56 compared to 20-28 days. Animals fed PROB had greater (P < 0.05) intakes of DM (1184.56 g / d), crude protein (CP) (254.63 g /d) and neutral detergent fiber (NDF) (320.36 g / d) than animals fed EOPROB . Intake of Non-fibrous carbohydrates (NFC) were greater (P < 0.05) in EO (384.31 g / d) compared to CON (323.63 g / d), MON (323.84 g / d) and EOPROB (301.30 g / d). The ether extract (EE) and organic matter (OM) intake was not affected (P > 0.10) by treatments. NDF digestibility was greater (P < 0.012) in animals fed MON (924 g / d). In conclusion, EO can be added to the dairy calf ration to improve fecal score, increases DMI and improves nutrient digestibility. The pre-weaning FCI decreased with MON and increased with PROB