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| Author(s): |
Dimas Estrasulas de Oliveira
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Piracicaba. , gráficos, ilustrações, tabelas. |
| Institution: | Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC) |
| Defense date: | 2003-09-12 |
| Examining board members: |
Dante Pazzanese Duarte Lanna;
Paulo Roberto Leme;
Carlos Guilherme Silveira Pedreira;
Enio Rosa Prates;
Sila Carneiro da Silva
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| Advisor: | Dante Pazzanese Duarte Lanna |
| Field of knowledge: | Agronomical Sciences - Animal Husbandry |
| Indexed in: | Banco de Dados Bibliográficos da USP-DEDALUS; Biblioteca Digital de Teses e Dissertações - USP |
| Location: | Universidade de São Paulo. Biblioteca da Escola Superior de Agricultura Luiz de Queiroz; ESALQ-BC/t636.2084; O48u 82105 |
| Abstract | |
N-alkanes have been used as markers in studies of intake estimation and diet botanical and/or morphological composition with domestic and wild ruminants and non-ruminant animals. It has been done three experiments, which in the first was evaluated the n-alkanes release rate from controlled-release capsules in rumen-fistulated animals kept in metabolism cages. Also in the fist experiment was evaluated the validation of forage intake predictions for the animals allocated in three different forage : concentrate ratios. In the second experiment was evaluated the n-alkanes release-rate from controlled-release capsules with the same animals kept on pasture and allocated in three distinct treatments with concentrate supplementation. Release rates were measured with a caliper removing the capsule through ruminal fistula and measuring the distance passed through by the embolus capsule which push the tablets containing the marker at 3, 7, 10, 13, and 17 days after rumen insertion. There were not effect (P>0.05) of diet and interaction between diet and day of measure in the daily release rate both in the animals maintained on the metabolism cages as on pasture. It was possible to combine the equations generated from each experiment resulting in a marker released amount of 345 mg.d -1 . The estimated intake with the n-alkanes C33:C32 pair in the metabolism cage animals did no differ (P>0.05) from the actual intake. The objectives of the third experiment were to establish the n-alkanes profile on Cynodon nlemfüensis Vanderyst var nlemfüensis and to estimate intake and morphological composition of the forage consumed by lactating dairy cows on pasture supplemented with conjugated linoleic acid (CLA) or Megalac (MEG), using a linear regression between the requirements and the daily intake of metabolizable energy. It was found n-alkanes with the carbon chain length ranging between 22 and 35 atoms, being the odd chain prevalent over the even chain n-alkanes. The C33, C31, and C29 n-alkanes were found in higher concentrations. Among the even chain n-alkanes, the C26, C28, and C30 were found in higher concentrations. In the first study period the average forage dry matter intake did not differ (P>0.05) between the animals supplemented with CLA or controls (CLA = 11.2 vs. MEG = 11.1 kg.day -1 ). The total dry matter intake also did not differ (P>0.05) between treatments (CLA = 14.6 vs. MEG = 14.3 kg.day -1 ). In the third study period the average forage dry matter intake did not differ (P>0.05) between the animals supplemented with CLA or controls (CLA = 11.8 vs. MEG = 12.6 kg.day -1 ). The total dry matter intake also did not differ (P>0.05) between treatments (CLA = 15.4 vs. MEG = 16.2 kg.day -1 ). In the first study period, the estimates of forage intake and consumed plant parts were precise and accurate (b = 1, C.V. = 9.3 %), while in the third period the estimates were precise but inaccurate (b ≠1, C.V. = 5.0 %). (AU) | |