Browsing Grassland Science by Author "Cummins, B."
Conservation characteristics of grass and dry sugar beet pulp co-ensiled after different degrees of mixingCummins, B.; O'Kiely, Padraig; Keane, Michael G.; Kenny, David A.; Teagasc Walsh Fellowship Programme (Teagasc, Oak Park, Carlow, Ireland, 2007)The objective of this experiment was to quantify the effects of the degree of mixing of dry molassed sugar beet pulp (BP) with grass on silage conservation characteristics. Herbage from a timothy (Phleum pratense) sward was precision chopped and treated with a formic acid based additive (3 l/t grass). Units of 50 kg grass, without or with 2.5kg BP were randomly allocated among four replicates on each of seven treatments. The treatments were (1) no BP (NONE), (2) BP evenly mixed through the grass (EVEN), (3) BP evenly mixed through the lower 25 kg grass (LOWH), (4) BP evenly mixed through the lower 12.5 kg grass (LOWQ), (5) 0.625 kg BP mixed through the top 25 kg grass and 1.875 kg SBP mixed through the lower 25 kg grass (25/75), (6) BP placed in 0.5 kg layers beneath each 10 kg grass (LAYR), and (7) BP placed in a single layer under all of the grass (BOTM). Laboratory silos were filled and sealed, and stored at 15 °C for 163 days. Effluent was collected and weighed from each silo throughout the ensilage period. At opening, silage composition and aerobic stability measurements were made. Total outflow of effluent was reduced (P<0.001) by the addition of BP; LAYR had a greater effect (P<0.001) than any of the other treatments. Effluent dry matter (DM) concentration was highest (P<0.05) for BOTM and lowest (P<0.01) for NONE. All treatments underwent similar lactic-acid dominant fermentations. Incorporation of BP with grass increased silage DM concentration (P<0.001), in vitro DM digestibility (P<0.05) and water soluble carbohydrate (P<0.001) concentration and reduced acid detergent fibre (P<0.001) concentration. Aerobic stability was similar across treatments and aerobic deterioration at 192 h was higher (P<0.05) for LOWQ, 25/75, LAYR and BOTM than for NONE. In conclusion, the incorporation of BP increased silage DM digestibility but had relatively little effect on fermentation or aerobic stability. Placing BP in layers gave the largest and most sustained restriction in effluent output.
Effects of breed type, silage harvest date and pattern of offering concentrates on intake, performance and carcass traits of finishing steersCummins, B.; Keane, Michael G.; O'Kiely, Padraig; Kenny, David A.; Teagasc Walsh Fellowship Programme (Teagasc, Oak Park, Carlow, Ireland, 2007)The objective of this experiment was to investigate the effects and interactions of breed type, silage harvest date and pattern of offering concentrates on intake, performance and carcass traits of finishing steers. Seventy-two steers (36 Friesian and 36 beef cross) were blocked on weight within breed type and assigned to a pre-experimental slaughter group or to one of 4 dietary treatments in a 2 (breed type) 2 (early- or late- cut silage) 2 (flat rate or varied pattern of offering concentrates) factorial arrangement of treatments. The flat-rate feeding pattern was silage ad libitum plus 5 kg concentrates per head daily to slaughter. The varied feeding pattern was silage only for 79 days followed by concentrates ad libitum to slaughter. All animals were slaughtered together after 164 days when the groups on the two feeding patterns had consumed the same total quantity of concentrates. Friesians had a higher (P < 0.001) silage dry matter (DM) intake and a higher (P < 0.01) total DM intake than the beef crosses. Live-weight gain was similar for both breed types but the beef-cross animals had a higher (P < 0.001) kill-out proportion, higher (P < 0.01) carcass gain, and better (P < 0.001) carcass conformation than the Friesians. The beef-cross type also had a higher (P < 0.001) proportion of muscle and a lower (P < 0.001) proportion of bone in the carcass. Silage harvest date had no effect on silage or total DM intakes but the early-cut silage did result in higher (P < 0.01) carcass gain. Animals on the varied feeding pattern consumed less (P < 0.01) silage DM and less (P < 0.001) total DM than those on the flat rate feeding pattern. Live-weight gain and carcass gain were similar for the two feeding patterns. It is concluded that Friesians had a higher intake, but had lower carcass gain than the beef-cross type. Animals on the early-cut silage had higher carcass gain than those on the late-cut silage. The varied feeding pattern resulted in lower DM intake but efficiency of feed energy utilisation was similar for both feeding patterns. Interactions were generally not statistically significant.
Feed intake pattern, behaviour, rumen characteristics and blood metabolites of finishing beef steers offered total mixed rations constituted at feeding or ensilingCummins, B.; O'Kiely, Padraig; Keane, Michael G.; Kenny, David A.; Teagasc Walsh Fellowship Programme (Teagasc, Oak Park, Carlow, Ireland, 2009)Two experiments were undertaken. In Experiment 1, behaviour, intake pattern and blood metabolites, were recorded for steers offered total mixed rations (TMR) based on grass silage and concentrates, and constituted either at ensiling (E-TMR) or feedout (F-TMR). Fourteen continental crossbred steers (mean starting weight 505 (s.d. 41.5) kg) were assigned to each of the following eight treatments: grass silage offered ad libitum (SO), E-TMR diets constituted in approximate dry matter (DM) ratios of grass:concentrates of 75:25 (EL), 50:50 (EM) and 25:75 (EH), F-TMR diets constituted in approximate DM ratios of grass silage:concentrates of 75:25 (FL), 50:50 (FM) and 25:75 (FH), and finally concentrates ad libitum (AL). Total DM intake increased linearly (P < 0.001) and the time spent eating and ruminating decreased linearly (P < 0.001) with increasing concentrate proportion. Animals on the F-TMR diets had higher total DM intakes (P < 0.05) and plasma glucose (P < 0.05) and urea (P < 0.001) concentrations than animals on the corresponding E-TMR diets. No effect of method of feed preparation on intake pattern or behaviour was recorded. In Experiment 2, four ruminally cannulated Holstein-Friesian steers of mean initial live weight 630 (s.d. 23.2) kg were used to evaluate rumen characteristics for four of the above diets (FL, EL, FH and EH) in a 4 × 4 latin square design. Higher concentrate diets resulted in lower rumen pH (P < 0.05), higher lactic acid (P < 0.001) and ammonia (P < 0.05) concentrations and lower acetate:propionate (P < 0.05). F-TMR was associated with a higher (P < 0.05) rumen volatile fatty acid concentration but no difference in other rumen fermentation characteristics compared to E-TMR. Concentrate proportion and method of feed preparation had no effect (P > 0.05) on rumen pool sizes but animals consuming the high concentrate diet had a faster (P < 0.05) rumen passage rate of NDF than animals on the low concentrate diet.