A calorimetric investigation of the nutritive value of formic acid- and formaldehyde—Formic acid-treated grass silages

Experiments were conducted to study the utilisation of a ryegrass mixture preserved chemically by formic acid (silage 1) of mean gross energy (GE) 18.6 MJ/kg dry matter (DM), and formaldehyde—formic acid (silage 2) of mean GE 18.3 MJ/kg DM. The parent grass and resulting silages were analysed chemically and calorimetric balance trials were performed with four sheep fed at maintenance and 1.5 times maintenance.Silages 1 and 2 had similar, high digestibility coefficients for DM (0.732 and 0.718), organic matter (OM) (0.755 and 0.742), and energy (E) (0.730 and 0.710). The digestible energy (DE) contents of silages 1 and 2 were 13.3 and 12.7 MJ/kg DM, respectively, at the lower level of feeding and 13.8 and 12.8 MJ/kg DM, respectively, at the higher level. The metabolisable energy (ME) contents of silages 1 and 2 were 11.6 and 10.8 MJ/kg DM, respectively, at the lower level of feeding and 12.0 and 11.0 MJ/kg DM, respectively, at the higher level.The mean efficiency of utilisation of ME for growth (K_g) for silages 1 and 2 was 0.43 and 0.39, respectively; these results are in broad agreement with those predicted by other workers.     

Auditory brainstem responses in ground squirrels arousing from hibernation

Summary Auditory brainstem responses (ABRs) were recorded in ground squirrels (Citellus lateralis) arousing from hibernation. Squirrels implanted with recording screws to record ABRs, and a thermistor to record brain temperature, were placed in a cold room at 9 °C on a 2L:22D light-dark cycle. Hibernating animals were moved from the cold room and ABRs recorded during arousal. The responses showed a gradual development of all brainstem peaks.At low temperatures there were very long latencies to the peaks. The amplitudes of the peaks increased (with fluctuations) as brain temperature increased. The data indicate that neural generators on the brainstem auditory pathway were all activated early in arousal.These results do not support the hypothesis that successive peaks appear and grow in amplitude only after previous peaks are fully developed.     

Energy and nitrogen balance,intake and growth rate of lambs fed on unwilted grass silages treated with a formaldehyde—Acid mixture or untreated

Wether lambs were fed on precision-chopped first-cut ryegrass silage ad libitum in an intake trial, and a maintenance and 1.5 times maintenance in balance trials.The untreated and treated silages had pH values of 4.72 and 4.40, mean dry matter (DM) contents of 176 and 184 g kg^?1 and mean gross energy (GE) contents of 18.8 and 19.0 MJ/kg DM, respectively.Mean digestibility coefficients of DM (0.787 and 0.783), organic matter (OM) (0.827 and 0.820) and GE (0.794 and 0.793), for the treated and untreated silages respectively, were high. The metabolisable energy (ME) contents of the untreated and treated silages were 12.52 and 12.76 MJ/kg DM at maintenance and 11.94 and 12.56 MJ/kg DM at 1.5 times maintenance, respectively. The mean efficiency of utilisation of ME of the untreated and treated silages was 0.65 and 0.66 for maintenance (k_m) and 0.34 ± 0.134 and 0.40 ± 0.069 for growth (k_g), respectively; the k_g values were lower than expected.Dry matter intakes of these silages when given ad libitum were 27.9 and 28.8 g/kg W per day and produced live weight gains of 129 and 140 g day^?1 for the untreated and treated silages, respectively. These gains were similar to predicted values for live weight gain only when the experimentally determined k_g and k_m values were substituted in the equation of the Agricultural Research Council (1980) used for calculating the daily metabolisable energy requirements for live weight gain.