Qualitative and Quantitative Changes in Milk Fat during Lactation in the Tammar Wallaby (Macro pus eugenii)

Abstract

There are major quantitative and qualitative changes in the milk lipids during lactation in the tammar wallaby, Macropus eugenii. The crude lipid content of the milk is relatively low during the first 10 weeks of lactation; between 10 and 26 weeks post partum the lipid content increases gradually but after that it increases rapidly. The triglyceride fraction of the lipid at early stages oflactation contains a large amount of palmitic acid and relatively little oleic acid whereas mature milk exhibits little palmitic and much oleic acid. In the early stages of lactation fat represents 15% of the total solids and carbohydrate 55%; around 26-30 weeks post partum the carbohydrate moiety falls sharply to a level less than 2% of the solids while lipids increase to c. 60% of the solids. These changes coincide with increases in milk solids, emergence of the young from the pouch, ingestion of herbage, and fermentation of cellulose in the stomach.

Milk Composition in the Northern Brown Bandicoot, Isoodon macrourus (Peramelidae, Marsupialia)

“…Carbohydrate concentrations were determined as total hexose using the methods of Messer and Green (1979) and crude lipid determinations by the methods of Green et al (1983). In the first 30-35 days of lactation the quantity of milk available for collection was small making analysis for lipid difficult.…”

Composition of Milk from Red and Grey Kangaroos with Particular Reference to Vitamins

“…Since the collection of milk samples analysed in this study, more recent investigations (Griffith et al 1972;Messer and Green 1979;Green et al 1980) have revealed aspects of qualitative changes in milk drawn in sequential samples from kangaroos throughout lactation. As the aim of this study was to collect over the shortest possible time sufficient milk at known stages of lactation, to permit as many assays as possible, including for the first time, assessment of the vitamin content, it was not possible to monitor in such detail changes in the composition of the milk throughout lactation.…”

“…More recent investigations have examined aspects of diverse constituents in milks from a wider range of marsupial species. For example, from among the subfamily Macropodinae, amino acids have been investigated by Renfree:et al (1982); proteins by Jordan and Morgan (1968), Bell et al (1980) and Green et al (1980); carbohydrates by Messer and Mossop (1977) and Messer and Green (1979); and lipids by Glass et al (1967), Griffiths et al (1972) and Grigor (1980). Several of these studies together with that undertaken by Lemon and Barker (1967) have followed both qualitative and quanIitative changes during lactation and, in addition, Lemon and Bailey (1966) have confirmed qualitative differences in the whey proteins of milk drawn from separate gland~ of the one animal.…”

Developmental changes in the electroencephalogram and responses to a noxious stimulus in anaesthetized tammar wallaby joeys (Macropus eugenii eugenii)

“…The cut-off point of 185 days was used as a series of major nutritional and physiological changes occur at this age including the achievement of homeothermic control, elaboration of locomotive behaviour and changes in nutrient intake which are mainly due to changes in composition of maternal milk. 16,38,39 Experimental procedure All experiments were conducted during daylight between 09:00 and 16:00 h. Joeys were anaesthetized in a 25 L chamber with 4% halothane (Merial, Parramatta, Australia) in oxygen delivered at 5 L/min. They were intubated with the aid of a guidewire once loss of the righting reflex and absence of general body movements were achieved.…”