Productivity and physiological response of lactating Holstein cows to sugarcane supplementation and evaporative cooling under heat-stress

Autor(es)

Campos, F. P. ^[1] ; Conceicao, M. R. G. ^[2] ; Sarmento, P. ^[1] ; Nicacio, D. R. O. ^[2] ; Lima, C. G. ^[3] ; Matarazzo, S. V. ^[4]

Afiliação do(s) autor(es)

^[1] IZ APTA SAA, Inst Zootechny, BR-13380011 Nova Odessa, SP - Brazil

^[2] IZ APTA SAA, Inst Zootechny, Postgrad Program, Sustainable Anim Prod, BR-13380011 Nova Odessa, SP - Brazil

^[3] Univ Sao Paulo, Dept Basic Sci, FZEA, BR-13635900 Pirassununga, SP - Brazil

^[4] Univ Santa Cruz, Dept Anim Sci, UESC, Km 16, Rodovia Ilheus Itabuna, BR-13635900 Ilheus, Ba - Brazil

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF AGRICULTURAL SCIENCE; v. 156, n. 7, p. 900-913, SEP 2018.
• Citações Web of Science: 0

Resumo

The objective of the current study was to evaluate the effects of sugarcane and maize silage mixture v. maize silage in diets of Holstein cows and investigate performance under two environmental conditions. The cows were placed in freestalls, with individuals and stalls assigned to one of four treatments according to a replicated 4 x 4 Latin square design with 20-day periods divided into 11 days of adaptation (wash-out period) and 9 days of collection. Treatments were arranged in a 2 x 2 x 2 factorial design: total diets (maize silage (MS-based diet), the roughage mixture (RM-based diet, sugarcane: maize silage, 500 : 500 g/kg DM) plus concentrate); environmental conditions (with (W) and without (Wo) fan and nebulizers); and measurement times (09.40 and 14.00 h). The temperature and relative humidity was higher at 14.00 h and contributed to increased temperature-humidity index (76.6, W v. 75.9, Wo). Feed dry matter intake (DMI) was similar between diets (20.2 kg/day), but milk production and feed efficiency were lower with RM. Under W conditions, higher fat content and total solids of milk were observed with the RM-based diet, while crude protein and lactose were higher with MS. The Wo conditions increased body surface temperature (BS) in cows fed MS. The rectal temperature (RT) was higher with RM. The BS, RT and respiratory rate were higher at 14.00 h (34.9, 38.6 degrees C and 58.2 breaths/min) than at 09.40 h. The RM-based diet maintained DMI and milk composition, but not milk production. The use of the cooling system led to higher DMI and feed N efficiency use. (AU)

• Processo FAPESP: 05/50926-0 - Producao de vacas leiteiras submetidas as dietas isoproteicas em sistema de confinamento tipo freestall levando em consideracao fontes de volumosos e ambiencia.
• Beneficiário: Fábio Prudêncio de Campos
• Modalidade de apoio: Auxílio à Pesquisa - Regular