The reaction of pentoses with anthrone

The effects on milk solids production, ruminal metabolites, and microbial protein synthesis of four pasture-based diets were investigated. Two pastures (high or low nitrogen content (HN, LN) each with and without nonstructural carbohydrate supplementation (+NSC, -NSC, at 10% of metabolisable energy intake) were offered to eight stall held, rumen-fistulated Friesian cows during four 14-day periods in early to mid lactation in a Latin square design. HN and LN pastures contained 2.8 and 2.1% N, respectively. Total daily dry matter intakes averaged 15.6, 14.5, 15.3, and 14.3 kg on HN+NSC, HN-NSC, LN+NSC, and LN-NSC, respectively. NSC supplementation had no effect on milk and milk fat yields but increased milk protein yield by 0.04 kg/ day on HN pasture. Yields of milk, fat, and protein were higher on HN than LN pasture but microbial protein synthesis (MPS, g N/day) was not affected by type of pasture. MPS and efficiency of MPS (g N/kg digestible organic matter intake) were increased by NSC supplementation on HN pasture but not on LN pasture. Ruminal ammonia concentration and total tract N digestibility were reduced by NSC supplementation on both pastures and were lower on LN compared with HN pasture. The results indicated that pasture type affected response to NSC supplementation and that on HN but not LN pasture NSC supplementation improved N utilisation in the rumen and increased milk protein output. A97013

Section: Analytical Proceduresmentioning

confidence: 99%

Milk production and ruminal metabolites from cows offered two pasture diets supplemented with non‐structural carbohydrate

Carruthers¹,

Neil²

1997

“…Herbage samples from 2-4 samplings each spring were analysed for major minerals by atomic absorption spectrometry, MAD fibre (Clancy & Wilson 1966), in vitro organic matter digestibility (Minson & McLeod, 1972), water-soluble carbohydrates (Bailey 1958), total nitrogen (N), soluble N, soluble protein N, and soluble nonprotein N by Kjeldahl digestion.…”

Section: Chemicalmentioning

confidence: 99%

Grazing management and pasture composition on paired farms which differed in the incidence of bloat

Carruthers¹,

1994

Farm practices, pasture species, and pre-and post-grazing herbage masses were monitored monthly from June 1990 to April 1991 and from August to November in 1991 and 1992 on 16 pairs of dairy farms. Each pair included one farm with a history of bloat despite routine use of preventatives (bloat-prone) and one farm which historically rarely observed bloat in the absence of chemical use (bloat-free). Farms within a pair were on similar soil types and herds had similar genetic backgrounds. The incidence of bloat during spring was low in all years. Bloat-free farms averaged less ryegrass (58 versus 66%) and more grasses other than ryegrass (25 versus 17%) in pasture and higher pre-and post-grazing herbage masses than bloat-prone farms in 1990 and 1991. Bloat-free and bloat-prone farms did not differ in white clover content, soil fertility, milksolids production, or stocking rate. The differences in pasture species and herbage mass suggested that differences in management between bloat-free and bloat-prone farms may be associated with incidence of bloat under mild bloat conditions, but their role in influencing the occurrence of severe bloat could not be assessed.

“…Analyses of herbages, juice, urine, faeces, and refusals included nitrogen (N) by macro kjeldhal, acid detergent fibre (Clancy & Wilson 1966), total watersoluble sugars by the anthrone technique (Bailey 1958), gross energy (E) determinations by adiabatic calorimetry, and mineral analyses by atomic absorption spectrometry. Milk was analysed by IRMA.…”

Section: Analysesmentioning

confidence: 99%

Nutritive value of pressed herbage residues for lactating dairy cows

Bryant¹,

Carruthers

Trigg

1983

Results are presented from 11 trials evaluating the nutritive value of pressed pasture (PP) or pressed lucerne (PL) when fed fresh to lactating dairy cows. Extraction of juice from pasture removed, on average, 21070 of the dry matter (DM) and 30% of the nitrogen (N) present. Cows offered PP ad libitum in stalls consumed 8070 less DM and produced 9% less milk than cows offered pasture. Apparent digestibilities of DM, organic matter (OM), N, and energy (E) were reduced by 3.4,3.1,3.3, and 3.2 percentage units respectively, by extraction. In field trials, milk yield was also reduced by 9% although PP intake was supplemented by the grazing of pasture stubble. Juice extraction had little effect on milk fat or lactose content with inconsistent effects on milk protein content. Mineral or carbohydrate supplementation of PP had no effect on PP intake, milk production, or apparent digestibility of the ration. Extraction of juice from lucerne removed, on average, 25% of the DM and 38% of the N present. Ad libitum intake and milk yield of cows on PL were 7 and 10% less respectively than those on lucerne. Apparent digestibilities of DM, OM, N, and E were reduced by 3.2,3.6,5.6, and 4.3 percentage units, respectivelyby the extraction process. Effects on milk composition were not significant except for a decrease in protein content in one trial. Double extraction of lucerne removed 33% of the DM and 52% of the N present and resulted in larger reductions in N digestibility, intake, and milk yield, than obtained following a single extraction.