Data/hora: 18/06/2024 04:18:10

Biblioteca(s): 	Embrapa Gado de Corte.	
Data corrente: 	22/08/2000	
Data da última atualização: 	01/11/2013	
Autoria: 	VIEIRA, J. M.	
Título: 	The effect of type of pasture and stocking rate on pasture characteristics, animal behaviour and production.	
Ano de publicação: 	1985	
Fonte/Imprenta: 	[S.l.]: Queensland University, 1985.	
Páginas: 	230p.	
Idioma: 	Inglês	
Notas: 	Tese Doutorado.	
Conteúdo: 	Pastures of Cenchrus ciliaria cv. Biloela (buffel grass) were grown either with Macroptilium atropurpureum cv. Siratro (BS) or with the application of 100 kg nitrogen (N/ha/yr (BN) at Narayan, southeast Queensland, and were grazed contrinuously at 1.1. 1.5 or 2.2. steers/ha. Measurements were made over a two-year period and the interrelationships of pasture characteristics, grazing behaviour and animal performance were explored. Dry matter (DM) availabitily was minimal in the late winter-early spring, greater in the second year (596 mm rainfall) than in the first year (483 mm), and enhanced by N application. Treatment differences arose from effects on  wet season growth. Log DM availability decreased linearly with increasing stocking rate: DM availability averaged 4130 and 1480 kg/ha in BN pastures and  2630 and 990 kg/ha in BS pastures respectively at 1.1 and 2.2 steers/ha. Compressed height of sward was well related to total DM availability but not to green DM. Green and total DM showed similar treatment and seasonal effects, but differences in green DM were realtively more pronounced, especially in the dry season when green DM varied from 12 to 39% total DM. Siratro contributed negligible forage in these abnormally dry years. N% of green buffel leaves was greater at high than low SR, grater in the  dry than the wet  season, and averaged  2.4% in BS  and 2.8% in BN pastures.  In vitro organic matter digestibility (IVOMD) was almost invariably grater than 60% and P% averaged 0,33%. Total pasture on ofter and pasture in the 10-40 cm height layers had much lower values for these attributes. Overall mean bulk density was 30.5, 8.8, 11.7 and 53 kg/ha/cm respectively for dead material, green buffel leaf, green buffel stem and total pasture. Bulk density was highest in May and decreased at low SR; the low values record indicate potential restriction of animal intake. Duration of cattle grazing tended to be greater at low levels of forage availability, as occurred at  high SR, but the seasonal values of 670, 636, 780 and 636 min/day respectively for November, February, May and August (a period of low feed availability) suggest that only limited compensation of increased grazing time applied. Green buffel grass constituted 63, 73, 58 and 17% of animal diet respectively in November, February, May and August. IVOMD of diet decreased in  May and August, and was lower at high SR in August, despite higher N% in this treatment. Generally N% and IVOMD of diet  were positively and linearly related to % green leaf in diet. The prediction of dietary composition from the  attributes of the pasture on offer was more successful if the latter were expressed as percent composition rather than as yield. Cattle lost weight in the dry season accordin to SR, and in the second year BN pastures had lower  livesweight losses than BS pastures as SR decreased. In the wet seasons weight gain was greater on BN pastures which showed negative and positive linear relationships between weight gain and SR in successive years. Weight gain showed a cubic from with time, indicating initial gains at increassing rates and decreassing rates of gain towards the end of the season. Rate of liveweight change (kg/day, x) was well related to green DM (Kg/ha,  x) in spring by the exponential function y = 1.209-2.704 e - 5.7oo, and in summer by the linear function y = 0.996-0065x; total DM showed similar relationships. In autumm the relationship was asymptotic but in winter weight change was poorly related to the low levels of green DM and was better related to total DM.  It is concluded that in the Narayen environment (1) Siratro based pastures in dry years are less productive than pastures receiving 100 units N, (ii) N and P concentrations and IVOMD of green buffel leaves are adequate for beef production and (iii) forage availability limits cattle growth at high SR whilst forage quality factors appear to be more limiting at low SR.	
Palavras-Chave: 	Buffel grass; Capaim buffel; Desempenho; Pasture; Protein production; Stoking density; Taxa de lactacao.	
Thesagro: 	Animal; Cenchrus ciliaris; Pastagem.	
Thesaurus Nal: 	behavior; grazing.	
Categoria do assunto: 	--	
Registro original: 	Embrapa Gado de Corte (CNPGC)	
Exemplares: 	CNPGC - (8047-1) - ADD - TS - PP - T659/85 - VIE - T659/85 - DIS