BREMM, C.

CARVALHO, P. C. F.

GENRO, T. C. M.

REFFATTI, M. V.

ROSSETTO, J.

English

Repository Open Access to Scientific Information from Embrapa

54ª. Reunião Anual da Sociedade Brasileira de Zootecnia 24 a 28 de Julho de 2017Hotel Bourbon Cataratas – Foz do Iguaçu – BrasilISSN 1983-4357Anais da 54ª. Reunião Anual da Sociedade Brasileira de Zootecnia | Foz do Iguaçu 2017 | ISSN 1983-4357 1226Validation of the n-alkane technique to estimate dry matter intake in sheepJusiane Rossetto*1, Teresa Cristina M. Genro², Paulo C.F. Carvalho¹, Mônica V. Reffatti3, Carolina Bremm¹1Federal University of Rio Grande do Sul, Porto Alegre/RS, Brazil; 2Embrapa South Livestock, Bagé/RS; 3Universidade estadual do Rio Grande do Sul, Cachoeira do Sul, RS.*Doctoral student – jusiane.rossetto@colaborador.embrapa.brThe objective of this work was to evaluate the accuracy of the n-alkanes marker to estimate the dry matter intake in sheep. The experiment was conducted at the agronomic experimental station of the Federal University of Rio Grande do Sul (Eldorado do Sul, RS, Brazil). Twelve male sheep with an average live weight of 35 kg were housed in metabolism cages, provided with feed and drinking troughs. Twice a day, at 9 am and 6 pm, the animals were fed with annual ryegrass (Lolium multiflorum) in four levels: 1.5, 2, 2.5% of live weight and ad libitum during two experimental periods. Each period had 10 days for adaptation to handling and diet, and 12 days to the evaluation of dry matter intake (DMI). The observed DMI was measured by subtracting leftovers from the total of dry matter offered. The estimated DMI was performed using the double n-alkanes technique. Each animal received orally, for 12 days in the morning feed, a cellulose pellet impregnated with about 63 mg of the external marker dotriacontane (C32). Forage sample was collected daily (from day seven to day 12) from the forage offered to the animals, and then all daily samples were homogenized to compose a single sample. From the seventh to the twelfth day of dosing, before pellet administration, fecal samples were collected per rectum, identified individually and frozen. At the end of the collection period, the samples from each animal was thawed and homogenized to compose one sample per animal. The estimated DMI was calculated from the concentration of n-alkane present in the forage and feces (C31 and C33) and its homologous pair dosed orally C32, using the C31-C32 and C32-C33 pairs. The DMI values were expressed as a percentage of live weight (%LW). The data were submitted to the regression analysis by the statistical program JMP (JMP Pro Version 12.0.1, 2015). The DMI estimated by the n-alkane C31 the equation generated was DMI= 0.4122 + 0.6152 * x, with r² = 88.95 (P<0.0001) and the DMI estimated using the n- alkane C33 the equation was DMI = 0.5655 + 0.6832 * x, r² = 87.69 (P<0.0001). Regardless of the pair used to estimate the dry matter intake, the values of the determination coefficient obtained were high showing accuracy when using the double n-alkanes technique to estimate sheep intake. However, estimated DMI was overestimated for both C33 and C31 n-alkane, with averages of 0.066 and 0.536% of the live weight, respectively. The accuracy of the intake estimates depends on the similarity of the fecal recovery rate of the natural and dosed n-alkane. In this work, C33 had a fecal recovery rate closer to that of C32, which showed a smaller difference between observed and estimated intake. Therefore, it can be concluded that the C32-C33 n-alkane pair can be used to estimate the dry matter intake of sheep fed with annual ryegrass.Keywords: annual ryegrass, dotriacontane (C32), hentriacontane (C31), tritriacontane (C33), markerTheme 9  |  Ruminant nutrition and production

Validation of the n-alkane technique to estimate dry matter intake in sheep.

http://www.alice.cnptia.embrapa.br/bitstream/doc/1074025/1/Rossettoetal2017.pdf

Validation of the n-alkane technique to estimate dry matter intake in sheep.

Abstract

Similar works

Full text

Available Versions

Repository Open Access to Scientific Information from Embrapa