ALBERT

Notes: An experiment involving forty-five British Friesian cows in mid-late lactation was carried out to evaluate the effects of ensiling on herbage digestibility, dry-matter intake and milk production. The herbage from the primary growth of a predominantly perennial ryegrass sward that had received 123 kg N ha−1 was zero grazed (ZG) from 27 April to 24 May 1992. Before going onto the experimental diets all animals were offered a common silage as the sole diet and dry-matter intakes and milk yields were recorded. The herbage was mown, picked-up with a precision-chop harvester and offered as the sole diet, twice daily, 10 fifteen cows that were on average 176 days into lactation. On May 20 herbage from the same sward was harvested identically to the ZG herbage and ensiled, alternative loads being untreated (UT) or treated with formic acid (2.4 l−1) (FA). For silages UT and FA respectively, pH values were 3.94 and 3.92 and ammonia nitrogen concentrations were 95 and 75 [g(kg total N−1)]. Forty-two days after ensiling, the silages were fed twice daily as the sole diet to thirty cows which were on average 166 days into lactation. The feeding interval was 28 days and the last 7 days was the main recording period for each treatment. For diets ZG, UT and FA, dry-matter intakes (DMI) (kg d−1), milk yields (kg d−1), fat plus protein yields (kg d−1). milk fat concentration (g kg−1), milk protein concentration (g kg−1)and fat plus protein yields [kg (kg DMI)−1] were 12.70, 11.51 and 12.07 (Av s.e.d. = 0.458); 12.79, 10.01 and 10.18 (Av s.e.d. = 0.346); 0.900, 0.649 and 0.682 (Av s.e.d. = 0.026); 39.8, 33.7 and 36.7 (Av s.e.d. = 0.174); 32.9, 29.9 and 30.0 (Av s.e.d. = 0.83); 0.073, 0.055 and 0.055 (Av s.e.d. = 0.003). UT treatment significantly increased dry matter (DM), organic matter (OM). energy and crude fibre digestibilities and the digestible OM concentration. UT and FA compared with ZG altered rumen fermentation patterns, significantly decreasing butyrate and increasing valerate concentrations. FA treatment significantly decreased the non-glucogenic ratio. It is concluded that ensiling using formic acid had no effect on forage DMI relative to the parent fresh herbage. Ensiling either untreated or with formic acid significantly decreased milk yield and milk fat plus protein yield, resulting in a lower efficiency of conversion of DMI to milk fat plus protein.

Notes: : The role of leucine aminopeptidase (LAP) from pig kidney cytosol and X-prolyldipeptidyl aminopeptidase (Pep X) from Lactococcus lactis subsp. cremoris AM2 in the hydrolysis and debittering of a tryptic digest of β-casein was studied. Hydrolysis was monitored by quantifying the release of primary amino groups and bitterness by use of a trained sensory panel. Sequential incubation of the bitter tryptic hydrolysate with LAP, Pep X and LAP resulted in higher levels of hydrolysis and significantly (P 〈 0.001) lower levels of bitterness than incubation with LAP alone. The results demonstrate the central role proline-specific aminopeptidases can play in the hydrolysis and debittering of food protein hydrolysates.

Notes: The influence of animal feed quality on lipid and cholesterol oxidation in whole milk powder was investigated. Powders from a herd receiving a ‘supplemented’ diet showed reduced PV (p 〈 0.01) and TBARS (p 〈 0.09) compared to a ‘restricted’ herd, after storage in both vacuum and sachet-packs and less (p 〈 0.003) cholesterol oxidation products (COPs). High pre-heating temperatures resulted in higher levels of PV, TBARS and COPs in fresh whole milk powders than low pre-heat temperatures, but after storage the reverse occurred. Superior animal feed quality and proper control of processing and storage conditions enhanced oxidative stability of whole milk powder. Lipid and cholesterol oxidation were positively correlated (p 〈 0.001).

Notes: This paper highlights the main disinfection options available for sewage, final effluents and stormwater, and is a review of the current research programme being carried out by staff of the Water Research Centre.Disinfection is an increasing requirement, with particular emphasis on bathing and recreational water use. Laboratory and field trials are reviewed, and a wide range of disinfectants have been tested. These include peracetic acid and the Clariflow process for crude sewage; peracetic acid, ozone and UV irradiation for final effluent; and peracetic acid for stormwater.The efficacy of the various disinfectants is evaluated and general costs are presented. Of special interest is the potential effect of sewage strength in reducing the disinfecting properties of the chemical. It is also apparent that there are wide variations in performance between processes and host organisms.

Notes: The UK approach to pollution control in tidal waters places considerable emphasis on balancing the contrasting needs of utilization of the waters for the assimilation of effluents with the protection of all identified uses, i.e. the Environmental Quality Objective/Environmental Quality Standard (EQO/EQS) approach. In order to protect uses of the waters for bathing and general amenity, this approach in the design of improvement schemes necessary for marine sewage discharges is examined. However, recent guidelines for consent applications dealing with schemes designed to protect bathing use suggest a departure from the EQO/EQS approach towards an emission standard when dealing with the solid phase of the sewage effluent. The implications of these approaches are discussed from the design (scientific and engineering) viewpoints.A summary of headworks processes and the current practice for preliminary treatment at marine outfall sites in the UK is reviewed, together with comments on their effectiveness. The terms of reference and work of a joint working group to examine the efficiency of screening equipment at marine outfall headworks is described, together with a technical summary of results collected at a range of sites and with various types of equipment. Recommendations for future research are given, and a strategy for screening is developed.