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This Article Full Text (PDF) All Versions of this Article: jas.2008-0940v1 86/12/3511    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Araujo, R. C. Articles by Eastridge, M. L. Search for Related Content PubMed PubMed Citation Articles by Araujo, R. C. Articles by Eastridge, M. L.

Milk yield, milk composition, eating behavior, and lamb performance of ewes fed diets containing soybean hulls replacing coastcross (Cynodon sp.) hay

R. C. Araujo^*, A. V. Pires^*, I. Susin^*, C. Q. Mendes^*, G. H. Rodrigues^*, I. U. Packer^* and M. L. Eastridge

^* Departamento de Zootecnia, Escola Superior de Agricultura "Luiz de Queiroz", Universidade de São Paulo, Piracicaba, São Paulo, Brazil Department of Animal Sciences, The Ohio State University, Columbus, 43210

alvpires{at}esalq.usp.br

Abstract

The objective of this experiment was to evaluate the effects of replacing coastcross hay NDF by soybean hull (SH) NDF on lactation performance and eating behavior of ewes and also on the performance of their lambs. Fifty-six Santa Inês lactating ewes (56.1 ± 6.8 kg of initial BW; mean ± SD) were penned individually and used in a randomized complete block design with 14 blocks and 4 treatments. Diets were formulated to provide similar concentrations of NDF (56%) and CP (16%). The SH NDF replaced 33 (SH33), 67 (SH67), or 100% (SH100) of the NDF contributed by coastcross hay in a 70% forage-based diet (SH0), resulting in SH inclusion rates of 0, 25, 54, and 85% of the dietary DM. Once a week, from the second to the eighth week of lactation (weaning time), ewes were separated from their lambs, stimulated by 6 IU oxytocin i.v. injection and hand milked to empty the udder. After 3 h, milk production was obtained after the same procedure. Quadratic effects for milk production (142.4, 179.8, 212.6, and 202.9 g/3 h) and DMI (2.27, 2.69, 3.25, and 3.00 kg/d) were observed as SH inclusion increased from 0 to 85% of the dietary DM. Milk fat (7.59, 7.86, 7.59, and 7.74%), protein (4.53, 4.43, 4.40, and 4.55%), and total solids (18.24, 18.54, 18.39, and 18.64%) did not differ among SH0, SH33, SH67, and SH100, respectively. A linear increase in lactose concentration was observed with SH inclusion. Ewe BW gain during the trial showed a cubic response (0.37, 0.03, 4.80, and 2.80 kg) with SH inclusion. The preweaning ADG of lambs increased linearly, and ADG of lambs after weaning decreased linearly with SH inclusion. Final BW of lambs (2 wk after weaning) did not differ among treatments. Eating behavior observations were conducted with 44 ewes. The same facilities, experimental design, dietary treatments, and feeding management were used. Observations were visually recorded every 5-min for a 24-h period when ewes were 46 ± 6.8 d in milk. Eating time (minutes per day, min/g of DMI, and min/g of NDF intake) and time expended in rumination and chewing activities (min/g of DMI and min/g of NDF intake) decreased linearly with addition of SH in the diets. The inclusion of SH improved DMI and milk production, also reflecting on BW of lambs at weaning. Milk performance was not affected when SH NDF replaced 100% of hay NDF.

Key Words: milk production • non-forage fiber source • particle size • Santa Inês • sheep • soybean hulls