Avaliação nutricional e utilização de Opuntia spp. na alimentação de pequenos ruminantes | Nutritional assessment and use of Opuntia spp. in the feeding of small ruminants

Oradora convidada para apresentar o tema Avaliação nutricional e utilização de Opuntia spp. na alimentação de pequenos ruminantes/Nutritional assessment and use of Opuntia spp. in the feeding of small ruminants

Cactus pear (Opuntia ficus-indica) was introduced in the Iberian Peninsula in the XVIth century. Today we can find the Opuntia genus plants in whole Portugal. Cladodes can be fed to small ruminants especially in periods of the year when there is low quality and quantity of pasture. Portugal is defined as having a Mediterranean climate with hot dry summers and mild wet winters, with irregular rainfall and semi-arid conditions in some regions. The use of O. ficus-indica cladodes as a forage for small ruminants has been very important in the semi-arid and arid regions of the world. In Portugal during the rainy season the availability of pasture is quantitatively and qualitatively satisfactory, but in critical times of the year the shortage and low nutritive value of forages causes decreased productivity in the ruminant’s production of milk and meat. The aim of this work is to present the nutritional cladodes profile of five different Portuguese ecotypes of O. ficus-indica and compare with two imported improved cultivars used by the Portuguese producers, evaluate its potential use as a feed for small ruminants and formulate a diet that maximizes the use of cladodes in the feeding of lactating ewes. We consider the relationship between the nutritional value and the cladodes number of spines. Cladodes with spines should not be used as feed for ruminants. The experimental field was installed in May 2012 in School of Agriculture - Polytechnic Institute of Castelo Branco (ESA-IPCB). Mature cladodes of O. ficus-indica were previously collected from fifteen plants of five different Portuguese ecotypes (PT1 - Portalegre; PT2 - Arronches; PT3 - Cacela-a-Velha; PT4 - Monforte da Beira; PT5 - Idanha-a-Velha) growing in Central and Southern Portugal and two improved cultivars (Gialla and Bianca), as a term of comparison. Direct planting without irrigation was used. During September 2013 one-year cladodes of experimental field were randomly harvested from five plants of each ecotype. In the Animal Nutrition and Feeding Laboratory of the ESA-IPCB, one-year cladodes were analysed. The average values obtained for the 42 samples analysed (5 ecotypes and 2 varieties) were the following: DM 13.68% (±1.26); ash 89.94 g/kgMS (±11.14); CP 75.02 g/kgMS (±8.72); EE 14.60 g/kgMS (±1.78); NDF 185.68 g/kgMS (±24.51); ADF 108.15 g/kgMS (±18.39); ADL 8.75 g/kgMS (±2.87); NFC 633.00 g/kgMS (±34.66); ME 11.23 MJ/kgMS (±0.21); TDN 74.25% (±1.38). Significant differences (p<0.05) were found in ash, CP and NFC content among O. ficus-indica populations. In general, O. ficus-indica has a low content of DM, CP and NDF and high content in NFC and EM. Due to the importance that DM, CP and the NDF have for ruminant’s nutrition and feeding we concluded that Opuntia spp. seems to be an interesting forage option for small ruminants in driest period of the year if animals have also access to dry forage and a raw material with high CP content.

N/A