Rotational stocking management affects the structural and nutritional characteristics of Guinea grass swards and milk productivity by crossbred dairy cows

Author(s)

Pereira Lima, Mara Lucia ^[1] ; Simili, Flavia Fernanda ^[1] ; Giacomini, Alessandra ^[2] ; Roma-Junior, Luis Carlos ^[1] ; Ribeiro, Enilson Geraldo ^[2] ; Paro de Paz, Claudia Cristina ^{[1, 3]}

Affiliation

^[1] Sao Paulo State Govt, Dept Agr, SAA APTA, BR-14030670 Ribeirao Preto, SP - Brazil

^[2] Inst Anim Sci IZ, BR-13460000 Nova Odessa, SP - Brazil

^[3] Univ Sao Paulo, Sch Med Ribeirao Preto, FMRP USP, Dept Genet, BR-14034990 Ribeirao Preto, SP - Brazil

• Document type: Journal article
• Source: ANIMAL FEED SCIENCE AND TECHNOLOGY; v. 186, n. 3-4, p. 131-138, DEC 13 2013.
• Web of Science Citations: 0

Abstract

The type of stocking system can affect sward canopy structure, changing the nutritional value of herbage and livestock production. The present study evaluated structural and nutritive features of Guinea grass (Panicum maximum Jacq. var. Tanzania) swards and the composition and yield of milk produced by crossbred cows fed this herbage in a rotational stocking system over cycles from Spring to Autumn. Two stocking systems were tested, in which cattle were allowed to graze: (I) after grazing cycles of 30 days (T-30d); or (2) when the sward reached a pre-grazing height of 70 cm (T-0.7m). Five grazing cycles, each consisting of a sward recovery period followed by 2 days of grazing, were evaluated in each stocking system using a completely randomized block design and repeated measures with 2 repetitions per stocking system (each composed of a set of sixteen 4000 m(2) paddocks grazed sequentially). Four 1 m x 1 m sward patches were collected, constituting one sample per paddock, which was used to evaluate pre-grazing herbage mass, leaf, stem and dead matter (dry mass per area), crude protein (CP), neutral detergent fiber (NDFom), acid detergent fiber (ADFom) and hemicellulose (HEM). Cows received daily supplementation of 4 kg concentrate. Stocking rate, milk production and composition were evaluated in each grazing cycle. The T-30d stocking system produced higher (P=0.0014) pre-grazing height than Turn (0.83 vs 0.69 cm), had higher (P=0.0071) light interception (94 vs 91%) and higher (P=0.0233) leaf area index (5.2 vs 4.5). In addition, T-30d exhibited larger (P=0.0204) herbage mass than T-0.7m (7276 vs 6187 kg MS/ha), higher (P= 0.0243) leaf dry mass per area (2618 vs 2294 kg/ha) and higher (P<0.0001) stocking rate (6.2 vs 5.7 animal/ha). The grazing cycle affected sward composition, with T-30d producing higher (P=0.0060) leaf NDFom. Milk production and composition was not affected by the stocking systems, as follows (T-30d vs T(0.7)m): 20.12 vs 20.94 kg milk production per cow/day; 31.4 vs 31.9 g fat/kg, 29.9 vs 30.2 g protein/kg, 43.7 vs 44.6 g lactose/kg, 114.8 vs 116.5 g/kg total solids and 12.85 vs 12.86 mg/dL ureic (AU)

• FAPESP's process: 07/04200-3 - Study of diferent grazing management in rotational grazing system
• Grantee: Maria Lucia Pereira Lima
• Support Opportunities: Regular Research Grants