Evaluation of essential oils and their route of administration for feeding dairy calves

Author(s)

Flavia Hermelina da Rocha Santos

• Document type: Master's Dissertation
• Press: Piracicaba.
• Institution: Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC)
• Defense date: 2014-01-24

Examining board members

Carla Maris Machado Bittar; Rafael Canonenco de Araujo; Julio Viégas

• Advisor: Carla Maris Machado Bittar

Abstract

The objective of this study was to evaluate the use of a commercial blend of essential oils, supplied via starter concentrate and/or milk replacer with regard to fecal scores, rumen fermentation and overall performance of the animals. Thirty Holstein calves were utilized and received 6L/d of liquid diet, consisting of commercial milk replacer (20CP:15EE), and had free access to water and starter concentrate. Weaning occurred at week 8, and the animals were followed until the 10th week of age. Animals were distributed in a randomized block design, in the following treatments: 1) Control: without supplementation with essential oils (C), 2) Supplementation: 400 mg/kg of blend of essential oils in milk replacer (M) and 3) Supplementation: 200 mg/kg of blend of essential oils in the milk replacer and 200 mg/kg in the starter concentrate (MRC). From the second week, calves were weighted and body measurements were taken, while concentrate intake and fecal scores were monitored daily. Furthermore, blood samples were drawn weekly for determination of hematocrit, glucose, ?-hydroxybutyrate and total proteins; as well as feces, for counting lactic acid bacteria and enterobacteria; and ruminal fluid for determination of pH, short chain fatty acids, ammonia-N and counts of amylolytic and cellulolytic, and protozoa. Performance, fecal scores and intestines microorganisms were not affected by the essential oils supplementation (P>0.05). Ruminal and blood parameters were also not affected (P>0.05), exception made for the rumen ammonia-N concentration, with higher values for animals supplemented through milk-replacer and starter concentrate (P<0.05). Most of the evaluated parameters were affected by age of animals, mainly as a response to the increase on concentrate intake as animal aged. Contrast analysis did not reveal a route of administration of essential oils effect (P>0.05), except for the wither´s height gains, being those higher for animals supplemented via milk-replacer (P<0.05). Essential oils are promising substitutes for antibiotic growth promoters. However, the dose and routes of administration deserve further studies, allowing a better animal performance and health to be achieved. (AU)

• FAPESP's process: 12/13561-8 - Essential oils as an alternative for antibiotics for dairy calves raising
• Grantee: Flávia Hermelina da Rocha Santos
• Support Opportunities: Scholarships in Brazil - Master