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Biomedical subjects

B Kefford

Publications and source records attributed to B Kefford.

9 recordsLinked to original sources
PubMed1999

Managing diet quality for Cheddar cheese manufacturing milk. 1. The influence of protein and energy supplements.

The effects of supplementing cows' diets with protein and energy on milk composition and the composition and yield of Cheddar cheese were investigated. This research addresses the problems of seasonal reduction in the capacity of cheese curds to expel moisture as observed in parts of south-eastern Australia. Milk was collected from cows offered a basal diet of silage and hay supplemented with different sources and levels of dietary protein and energy. The protein supplements were sunflower, canola, cottonseed meal and lupin, and the energy supplements were maize grain, oats, wheat and barely. This milk was used to manufacture Cheddar cheese on a pilot scale. Cheese moisture content was dependent on the source and level of dietary protein and energy. Milk from cows offered the lupin protein supplements and wheat energy supplements consistently produced cheese with a lower moisture content and moisture in fat-free matter. Milk from these supplemented diets had increased casein concentrations and higher proportions of alpha S2-casein than milk from the poor quality control diet. Cheese yield was directly related to the total casein concentration of milk, but was not influenced by differences in casein composition. Supplementing the cows' diets increased the inorganic P, Mg and Ca concentrations in milk. A low inorganic P concentration in milk from cows offered the control diet was caused by a low intake of dietary P. These findings showed that changes in the mineral and casein composition of milk, associated with diet, could influence the composition of Cheddar cheese.

Animals↗
PubMed1999

Managing diet quality for cheddar cheese manufacturing milk. 2. Pasture v. grain supplements.

The effects of supplementing a basal diet of silage and hay with increasing amounts of harvested spring pasture, or with lupin and wheat, on the composition of milk and the consequent effects on cheese composition and yield were investigated in an indoor feeding study. Milk was collected from five groups of eight cows in mid lactation offered different diets and manufactured into Cheddar cheese on a pilot scale. Milk from cows given the lupin-wheat (LW) and the high pasture level (HP) diets produced low moisture cheese. Cheese produced with milk from cows given the control diet was high in moisture content compared with that made with milk from cows offered the LW diet. Cheese yields from the milk of cows offered the HP and LW diets were greater than from the milk of cows on the control diet, and were associated with the higher casein concentrations of these milks. Casein number was higher in milk from diets supplemented with pasture but was not an indicator of the functional properties of milk that affected cheese moisture. The proportion of beta-casein in milk from cows offered the HP diet was higher and that of gamma-casein lower than in milk from cows given the LW supplement, although cheese moisture content was similar with both diets. Milk from cows offered the HP diet had a greater inorganic P concentration than that from cows given the LW diet, although the dietary intake of P was higher for the LW diet. The significance of the effect of dietary P intake on the concentration of inorganic P in milk and hence its suitability for cheesemaking was apparent when dietary P intake was low, as shown in milk produced by cows offered the control diet.

Animals↗
PubMed1995

Seasonal influences on Cheddar cheese manufacture: influence of diet quality and stage of lactation.

The influence of diet quality and stage of lactation on Cheddar cheese moisture and yield were segregated and the effects of other potential variables (cow breed, milk protein genotype, age and level of mastitis) were minimized. An experiment was conducted using milk of cows in mid lactation or late lactation fed on high or low quality diets. Increased moisture in cheese was largely due to the influence of cow diet. Milk from cows given high quality diets produced lower moisture cheese. Cheese yield was influenced by diet and stage of lactation. Cows in late lactation fed on high quality diets always gave milks yielding the most cheese. Fat and protein recovery in cheese was not influenced by diet or stage of lactation. The results suggest that low quality diets may induce changes in the complex interactions of milk proteins and other components that affect cheesemaking.

Animal Feed↗
PubMed1984

Adhesion of Leptospira at a solid-liquid interface: a model.

Two strains of the saprophytic Leptospira biflexa serovar patoc display reversible and irreversible adhesion at a solid-liquid interface. Both forms of adhesion are enhanced in the presence of 20 microM carbonyl cyanide meta-chlorophenyl hydrazone (CCCP), an uncoupler which inhibits motility of the bacteria. Microscopic observations also indicated that motility may have a role in adhesion as only actively motile organisms were seen to detach from the substratum. A dynamic model is proposed for adhesion of these organisms at a solid-liquid interface. It is suggested that the level of reversible adhesion is determined by the comparative rates of attachment (ON phase) and detachment (OFF phase). As reversible adhesion is mediated by weak forces of attraction, bacterial motility or gentle washing could promote the OFF phase. When motility is inhibited, the OFF phase is reduced and the ON phase continues (as motility is not required for the ON phase) causing the level of reversible adhesion to increase. Since reversible adhesion is a prerequisite for irreversible adhesion, then increased reversible adhesion leads directly to increased irreversible adhesion. Reversible adhesion appears to be mediated by the weak attractive forces of the "secondary minimum" whereas the mechanism facilitating irreversible adhesion of leptospires is not known.

Leptospira↗
PubMed1981

Mortalities associated with herpesvirus infection in captive macropods.

Fatal cases of herpesvirus infection in a quokka (Setonix brachyurus), eight grey dorcopsis wallabies (Dorcopsis muelleri luctuosa) in two separate outbreaks, as well as presumptive fatal herpesvirus infection in a western grey kangaroo (Macropus fuliginosus) are described. All were captive animals and deaths were preceded by a period of stress. Lesions occurred most often in alimentary tract epithelium, respiratory tract, skin, genital epithelium, conjunctivae, liver and adrenal cortex. Herpesviruses were recovered from the quokka and a grey dorcopsis wallaby from each outbreaks. The implications, particularly concerning certain apparently susceptible species, for those responsible for the health of macropod collections are discussed.

Animals↗
PubMed1979

An outbreak of disease in pigeons associated with a herpesvirus.

An outbreak of disease in young pigeons associated with a herpesvirus is reported. The clinical history, macroscopic and microscopic appearance of lesions and virus isolation are described. Most affected birds showed lesions in the upper alimentary tract epithelium as well as in skin, nasal mucosa and salivary glands. Lesions in liver, spleen and pancreas were uncommon. A herpesvirus capable of producing CPE on tissue culture and lesions on chorioallantoic membrane of developing chicken embryos was isolated and described. Inoculation of experimental pigeons with the virus failed to reproduce the disease.

Animals↗
PubMedDate not supplied

Serological identification of avian adenoviruses isolated from cases of inclusion body hepatitis in Victoria, Australia.

Sixteen avian adenoviruses isolated from 12 cases of inclusion body hepatitis (IBH), 3 cases of respiratory disease, and a case of ruptured tendons were compared using antisera raised against 9 fowl adenovirus prototype strains. Eleven isolates from livers of birds with IBH were classified into 4 different serological groups: 1) YR36 (type 7)-related; 2) HVI (type 8)-related; 3) Variants--type 6-,7-, and S-related; and 4) Type 50--not closely related to any of the prototype antisera tested. These results indicate that, as in other countries, IBH in Victoria is associated with several serologically distinct adenoviruses. The other five adenovirus isolates were found to be related to CELO (type 1).

Adenoviridae↗