Milk Consumption and Energetics of Growth in Pouch Young of the Tammar Wallaby, Macropus-Eugenii

1988 ◽  
Vol 36 (2) ◽  
pp. 217 ◽  
Author(s):  
B Green ◽  
JC Merchant ◽  
K Newgrain

Milk consumption rates of young tammar wallabies, Macropus eugenii, were measured during the first 32 weeks of lactation by means of 22*Na turnover. Milk consumption rates were low during the first 18 weeks or so of lactation, rising from 1.2 to 9.0 ml d-'. Milk consumption rose to 43 ml d-' at 30 weeks post-partum. Changes in milk consumption were paralleled by increases in the size of mammary glands and weight gain by the sucklings. The mass gain for each millilitre of milk consumed (crude growth efficiency) averaged 0.23 g ml-I during the first 26 weeks of lactation, but then increased to more than 0.35 g ml-'. The increased growth efficiency was associated with massive increases in the lipid and energy content of milk from 26 weeks onwards. The conversion efficiencies of milk protein and energy to body materials were intermediate (55-87%, 23-36%, respectively) to those of other mammals, which suggests that the slow growth of pouch young during the first 17 weeks of lactation is the result of restricted milk production by the mother. Milk production and the growth of young were closely correlated with maternal mass (r=0.96; r=0.80, respectively) at 16 weeks post-partum.

1997 ◽  
Vol 9 (2) ◽  
pp. 243 ◽  
Author(s):  
K. Basden ◽  
D. W. Cooper ◽  
E. M. Deane

A study has been made of the development of four lymphoid tissues from birth to maturity in the tammar wallaby Macropus eugenii —the cervical and thoracic thymus, lymph nodes and gut-associated lymphoid tissue (GALT). The development of these tissues in the tammar wallaby is similar to that in two other marsupials, the quokka Setonix brachyurus and the Virginian opossum Didelphis virginiana. Lymphocytes were first detected in the cervical thymus of the tammar at Day 2 post partum and in the thoracic thymus at Day 6. They were subsequently detected in lymph nodes at Day 4 and in the spleen by Day 12 but were not apparent in the GALT until around Day 90 post partum. By Day 21, the cervical thymus had developed distinct areas of cortex and medulla and Hassall’s corpuscles were apparent. The maturation of other tissues followed with Hassall’s corpuscles in the thoracic thymus by Day 30 and nodules and germinal centres in the lymph nodes by Day 90. Measurement of immunoglobulin G concentrations in the serum of young animals indicated a rise in titre around Day 90 post partum, correlating with the apparent maturation of the lymphoid tissues.


1990 ◽  
Vol 2 (1) ◽  
pp. 79 ◽  
Author(s):  
TP Fletcher ◽  
G Shaw ◽  
MB Renfree

Female tammar wallabies were treated with the dopamine agonist bromocriptine at the end of pregnancy to suppress the peripartum pulse of plasma prolactin. The animals were subsequently observed, and a series of blood samples taken to define the hormonal profiles before and immediately after parturition. Birth was observed in 4/5 control animals and occurred in 8/9 bromocriptine-treated animals. The peripartum peak in plasma PGFM concentrations was not affected by bromocriptine although the pulse of prolactin normally seen at parturition was completely abolished. The timing of luteolysis was apparently unaffected, as plasma progesterone concentrations fell similarly in both treated and control animals immediately after parturition. However, all of the neonates of the bromocriptine-treated animals died within 24 h, possibly because of a failure to establish lactation. Subsequent onset of post-partum oestrus was delayed or absent both in control and in bromocriptine-treated animals, suggesting that the frequent blood sampling and disturbances in the peripartum period interfered with these endocrine processes. It is concluded that both prolactin and prostaglandin can induce luteolysis in the pregnant wallaby, but that the normal sequence of events results from a signal of fetal origin inducing a prostaglandin release from the uterus, which in turn releases a pulse of prolactin that induces a progesterone decline.


2010 ◽  
Vol 58 (2) ◽  
pp. 121 ◽  
Author(s):  
S. J. Miller ◽  
R. Bencini ◽  
P. E. Hartmann

We investigated the consumption of milk by the young quokka using the stable isotope deuterium oxide. The volume of milk consumed increased from 1.6 mL day–1 at 55 days post partum to 32.5 mL day–1 at 165 days. The daily energy intake ranged from ~22 to 151 kJ day–1 during pouch life. The crude growth efficiency (grams of growth per millilitre of milk consumed) increased from an average of 0.35 to 0.46 g mL–1 in the early stages of pouch life, and then decreased to 0.24 g mL–1 during Phase 2b of lactation. The crude growth efficiency measured in our study indicates that quokkas are equally efficient in converting milk energy to body mass as other marsupials reported in the literature. Measuring milk intake with this method offers a non-toxic, minimally invasive alternative to other techniques for measuring milk consumption in marsupials, when milk is the only source of water intake.


1983 ◽  
Vol 96 (1) ◽  
pp. 155-161 ◽  
Author(s):  
C. H. Tyndale-Biscoe ◽  
L. A. Hinds ◽  
C. A. Horn ◽  
G. Jenkin

Concentrations of progesterone, prolactin, LH and 13,14 dihydro-15-keto-prostaglandin F2α (PGFM) were measured in plasma of eight tammar wallabies at 8-hourly intervals during the end of pregnancy and post-partum oestrus initiated by removing the pouch young, and during the end of the oestrous cycle, similarly initiated. In the non-pregnant cycle oestrus occurred 29·7 ± 0·7 (mean ±s.e.m.) days after initiation of the cycle, was preceded by a slow decline in progesterone concentration from 1·6 nmol/l to less than 0·64nmol/l and was followed by a preovulatory peak of LH 5·3± 3·9 h later. In the pregnant cycle birth occurred 26·1±0·2 days after removing the pouch young and was followed 8·0 ± 2·1 h later by oestrus and 16·0± 2·5 h by an LH peak. The latter events thus occurred 3·2 days earlier in the pregnant than in the non-pregnant cycle. Parturition coincided with a very rapid decline in progesterone and a transient high peak of prolactin. In two females sampled less than 25 min after parturition there was a transient peak of PGFM but in all others the concentrations of PGFM remained basal throughout. It is suggested that the fetus and/or placenta is involved in both the premature decline in progesterone and the initiation of parturition and that onset of oestrus and ovulation, being a consequence of a decline in progesterone, are therefore also determined by the fetus.


1996 ◽  
Vol 44 (6) ◽  
pp. 659 ◽  
Author(s):  
JC Merchant ◽  
H Marsh ◽  
P Spencer ◽  
G Death

Milk composition and the rates of milk consumption by pouch young were examined in free-living allied rock-wallabies, Petrogale assimilis. Milk solids concentrations were approximately 16% (w/w) at 70 days post-partum and increased to about 22% by 170 days when young first left the pouch. By permanent pouch emergence (about 200 days), concentrations had declined and stabilised at about 19%. Milk carbohydrate peaked at 12% (w/v) at 150 days; lipid concentrations averaged 8% (w/w) at 200 days. The subsequent decline in carbohydrates was the main cause of the fall in milk solids. Protein concentrations increased gradually from about 3% (w/v) at 70 days to plateau at 5.5% at about 200 days. Milk consumption rates were measured from 72 to 159 days post-partum with Na-22 turnover. Milk consumption, about 3 mL day(-1) initially, increased to an average of about 15 mL day(-1) by 150 days. The mass gained by a pouch young between 72 and 159 days for each millilitre of milk consumed was not correlated with lactational stage and averaged 0.21 +/- 0.014 (s.e.)g mL(-1).


1982 ◽  
Vol 30 (3) ◽  
pp. 399 ◽  
Author(s):  
DW Dellow ◽  
ID Hume

Urea and water metabolism were studied in the red-necked pademelon Thylogale thetis. and tammar wallaby Mucropus eugenii fed diets of chopped lucerne hay and fresh grass Phalaris aquatica ad libitum. On both diets T. thetis consumed more nitrogen (P<0.05), plasma urea levels were higher (P<0.05) and urea entry rate was greater (P<0.05) than in M. eugenii. Urea excretion rate was greater (P<0.05) in T. thetis than in M. eugenii on the lucerne diet, and urea degradation rate was greater (P<0.05) in T. thetis on the Phalaris diet. The proportion of urea synthesized that was recycled to and degraded in the digestive tract was similar (52-56%) in both species on both diets. T. thetis consumed more water (feed and drinking water) (P<0.05), and water turnover time was less (P<0.05) and turnover rate greater (P<0.05) than in M. eugenii, on both diets. At least on diets of adequate nitrogen and digestible energy content, it appears that differences in nitrogen metabolism between T. thetis and M. eugenii are not attributable to differences in gut microbial activity; rather, the results of this and other studies suggest that M. eugenii has a greater urine-concentrating ability and lower maintenance requirements than T. thetis.


1982 ◽  
Vol 35 (2) ◽  
pp. 145 ◽  
Author(s):  
Stuart W Green ◽  
Marilyn B Renfree

Samples of whey proteins from the milk of tammar wallabies, Macropus eugenii, were examined by acrylamide gel electrophoresis at all stages of lactation up to 280 days post partum. Whey albumin, ,B-globulin and y-globulin fractions had similar electrophoretic mobility to that of the equivalent serum protein fractions, but the proteins in the IX-globulin and pre-albumin regions differed markedly. The IX-globulins are presumed polymorphic because individuals at the same stage of lactation showed great variability in these electrophoretic regions: up to five polymorphic bands were recognized. Milk proteins changed qualitatively throughout lactation, and in particular the concentration of the pre-albumin and IX-globulin fractions increased from approximately day 180 to the end of lactation. Total protein concentration of both whole milk and whey approximately doubled in the second half of lactation compared to the first half, reaching maximum mean values of 114 � 47 and 96 � 50 g 1- 1 , respectively. Whole milk contained consistently more protein than whey, presumably due to the casein it contains.


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