Age estimation by measurement of pouch young of the Quokka (Setonix brachyurus).

1961 ◽  
Vol 9 (1) ◽  
pp. 14 ◽  
Author(s):  
JW Shield ◽  
P Woolley

Removal of pouch young of Setonix can lead to the resumption of development of quiescent blastocysts. Thirty-six pouch young obtained in this way have been used in this study. As the time in days from resumption of development to parturition is known, accurate ages may be calculated without actual birth or copulation being observed. These 36 animals have been repeatedly measured during their pouch life, and body weight, pes length, and tail length over the full term of pouch occupancy are given as regressions of these measures versus age. Larger-scale regressions are given for the first 80 days of pouch life. A tabulation based on the three regressions and giving average measures at stated ages is also given. During pouch life there is no difference in growth rate between male and female pouch young. Growth proportions of field-reared and compound-reared animals of comparable nutritional status are also similar. It is therefore considered that growth rates are equal, and that the age-estimation procedure established on compound-reared animals is applicable to field animals.

1977 ◽  
Vol 25 (1) ◽  
pp. 47-51 ◽  
Author(s):  
I. R. Hopkins

SUMMARYUsing pre-weaning records of 3822 calves from 11 Victorian herds, mean male and female growth rates and corresponding sex differences were calculated for each dam age and herd-year class. From these means simple regression equations relating sex differences and growth rates were calculated. There was a close similarity between equations based on dam age means and those based on herd-year means while correlations between sex differences and male growth rates were high.These results showed that sex differences and female growth rates could be predicted reliably from the level of environment as measured by male growth rate. Sex differences predicted by these regression relationships differed markedly from those predicted by the simple multiplicative and simple additive models generally used in adjusting for sex differences in selection.The results also suggested that other differences such as breed differences may be predictable in the same way and that such differences are determined primarily by the level of environment per se rather than differences in the nature of the components contributing to that level.


2004 ◽  
Vol 34 ◽  
pp. 57-66 ◽  
Author(s):  
A. Yilmaz ◽  
M. Ozcan ◽  
B. Ekiz ◽  
A. Ceyhan ◽  
A. Altine

SummaryThis study was carried out to investigate the fertility, milk production and body weight of ewes and the survival and growth characteristics of lambs of the indigenous Imroz and Kivircik sheep breeds. The Imroz and Kivircik sheep breeds are included among the genetic resources in the project for the conservation of the indigenous breeds in Turkey.Conception rates for Imroz and Kivircik ewes were 57.6% and 81.7% respectively, litter sizes were 1.2 and 1.2 respectively, milk yields were 89 kg and 62 kg respectively and average live weights (2–7 years of age) were 43 kg and 55 kg, respectively. Imroz and Kivircik lambs had survival rates at weaning (90th day) of 98% and 96%, birth weights of 3.3 kg and 4.1 kg and weaning weights of 19.8 kg and 28.0 kg, respectively.The results showed that the Kivircik sheep were heavier and the lambs had a better growth rate until weaning than the Imroz breed. However, the milk production of the Imroz ewes was higher than that of Kivircik. The lambs of both breeds had a satisfactory survival and growth rates until weaning and these results might be regarded as a desired adaptation of the Imroz and Kivircik lambs to the environmental conditions of the Marmara Region.


1979 ◽  
Vol 36 (12) ◽  
pp. 1497-1502 ◽  
Author(s):  
L. J. Buckley

The protein, DNA, and RNA content of larvae maintained at 1.0 plankter/mL increased at the rates of 9.3, 9.9, and 9.8% per day, respectively, for the 5 wk after hatching. Protein reserves of larvae held at 0 or 0.2 plankters/mL were depleted by 45 and 35%, respectively, prior to death 12–13 d after hatching. Starved larvae had similar protein concentrations (percent of dry weight), lower RNA concentrations, and higher DNA concentrations than fed larvae. Larvae held at higher plankton densities had higher RNA–DNA ratios and faster growth rates than larvae held at lower plankton densities. The RNA–DNA ratio was significantly correlated (P < 0.01) with the protein growth rate. The RNA–DNA ratio appears to be a useful index of nutritional status in larval Atlantic cod (Gadus morhua) and may be useful for determining if cod larvae were in a period of rapid or slow growth at the time of capture. Key words: RNA–DNA ratio, starvation, protein, nucleic acids, growth, larval fish, Atlantic cod


1930 ◽  
Vol 7 (2) ◽  
pp. 165-174
Author(s):  
M. A. TAZELAAR

Linear measurements of certain appendages and the carapace of P. carcinus were made and plotted in various ways. The following conclusions were drawn: 1. The cheliped shows heterogonic growth in both male and female, but more markedly in the male, the values of k being: male 1.8 and female 1.48 2. The pereiopods in both male and female are slightly heterogonic. The relative growth rates are graded from p3 to p5, that of p3 being slightly greater than that of p5 3. Of the ordinary pereiopods the rate of growth of p1 is the smallest in the male, but the largest in the female. 4. The difference between the rates of growth of p1 and p3 in male and female is greatest where the rate of growth in the heterogonic organ, the cheliped, is most excessive in the male. 5. The growth of the 3rd maxilliped is slightly negatively heterogonic, the value of k in the male being 0.93 and in the female 0.95. Hence there seems to be a correlation between the marked heterogony in the cheliped on the growth rate of neighbouring appendages. In those immediately posterior to the cheliped the growth rate is increased and in those anterior decreased.


Author(s):  
M Wan Zahari ◽  
J K Thompson ◽  
D Scott

The effects of plane of nutrition on the body composition of growing sheep are very apparent when animals are compared at the same age following different nutritional histories. These differences are, however, less obvious when animals of the same breed and sex are compared at the same body weight and at present there is some conjecture whether composition is affected by growth rate. This uncertainty is not limited to fat and protein but includes the bone and ash, fraction and the ash composition.The primary objective of this trial was to study the effects of different growth rates achieved by feeding different amounts of the same concentrate diet on the composition of empty-body gain and on the retention of minerals by growing lambs. A secondary objective was to examine the effect of adding supplementary calcium carbonate to the basal diet at the fast rate of growth.


1981 ◽  
Vol 59 (9) ◽  
pp. 1790-1795 ◽  
Author(s):  
Norman W. S. Quinn ◽  
Daniel M. Keppie

The influences of date of hatch, and age and prelaying body weight of brood female on the growth rate of juvenile spruce grouse (Canachites canadensis) were studied in central New Brunswick in 1977 and 1978. Because of differential timing of hatch of broods of adult and yearling females, it was not clear whether a difference in juvenile growth rates during 5–14 days of age in 1977 was related to date of hatch, age of brood female, or both. Differences in juvenile growth rates within and between years apparently were not influenced by body weight of brood females prior to egg laying. Results suggest that posthatch factors are more important in determining growth rate than a prehatch or "maternal" influence.


1991 ◽  
Vol 69 (4) ◽  
pp. 1040-1047 ◽  
Author(s):  
J. Ferron ◽  
J.-P. Ouellet

The physical and behavioral postnatal development of woodchucks (Marmota monax) was analyzed from birth to 42 days of age, the age at which weaning begins. Postnatal growth was evaluated by means of daily measurements of body weight, body length, tail length, and length of hind foot. Data on length of ear pinnae, vibrissae, and fur, and on the timing of appearance of some events of physical development are also presented. We considered postnatal development of locomotion, alertness, exploratory behavior, feeding, and comfort and social behavior. Our results indicate no sexual dimorphism in body size in young woodchucks, despite its occurrence in adults. Intraspecific comparisons reveal that woodchucks from different populations show marked variation in growth rate. The high level of intraspecific variation in developmental rates of sciurid rodents provides a warning to those performing interspecific comparisons. The data also suggest that the ratio of growth rate to adult body weight is not related to environmental severity. Behavioral development in M. monax is similar to that of ground squirrels but faster than that of tree squirrels and flying squirrels. There is also no direct relationship between size and timing of behavioral development in sciurid rodents. The behavioral repertoire of young woodchucks is simpler than that of young Spermophilus lateralis, another asocial species. It is possible that specific differences in rates of development of social interactions led to such differentiation in the repertoire of social behavior.


2000 ◽  
Vol 22 (1) ◽  
pp. 9 ◽  
Author(s):  
ML Hale

The inheritance of geographic variation in body size in the southern brown bandicoot (Isoodon obesulus) was investigated through a common-environment crossbreeding experiment. The geographic variation in body size is related to habitat type, suggesting that it may be adaptive. Adults from two locations in Western Australia, Perth (large animals) and Albany (small animals), were collected and offspring from both hybrid and non-hybrid matings were reared under controlled conditions. All four variables examined (head length, pes length, ear length and body weight) were found to possess a large genetic component, supporting the interpretation that the geographic variation in size is adaptive. The three length variables initially showed additive genetic variation, although the variation in body weight displayed dominance. Genetically controlled differences in growth rate were also detected, with the smaller animals, found in the relatively poorer environment, possessing the faster intrinsic growth rate. Thus, not only does there appear to be adaptive divergence in initial body size, but the countergradient variation in growth rates provides additional evidence for adaptive divergence in this species.


1998 ◽  
Vol 76 (5) ◽  
pp. 978-983 ◽  
Author(s):  
Hugo Ochoa-Acuña ◽  
John M Francis ◽  
Daryl J Boness

The objectives of this study were to establish body mass at birth, postnatal growth rate, and the factors that influence these parameters for the Juan Fernández fur seal, Arctocephalus philippii. Females of this species have an unusual attendance pattern in which foraging trips and shore visits last, on average, 12.3 and 5.3 days, respectively. Pup mass was obtained from cohorts born during the reproductive seasons in 1988 through 1992. Birth masses of male and female pups were significantly different, averaging 6.1 and 5.5 kg, respectively (F = 13.2, P < 0.0003, n = 238). Birth masses also differed among cohorts, being lowest in 1992 and highest in 1990. During the first 2 months of life, male and female pups grew at the same rate (79 ± 61.5 g · day-1 (mean ± SD); F[1] = 0.03, P = 0.8562). Interannual differences in growth rate during the first month were significant (F[4] = 8.14, P < 0.0001), as was the interaction between month and year effects (F[2] = 6.81, P = 0.0012). Growth rates for the 1990 cohort were lower than those in all other years except 1992. Birth masses and postnatal growth rates of Juan Fernández fur seal pups are comparable to those of other otariid species.


1967 ◽  
Vol 21 (4) ◽  
pp. 893-908 ◽  
Author(s):  
W. F. J. Cuthbertson ◽  
A. C. Laursen ◽  
D. A. H. Pratt

1. Both male and female Cynomolgus (Macaca irus) monkeys survived for 3 years without apparent ill health when fed on diets containing groundnut meal to provide up to 0·36 μg aflatoxin B1per g diet and thus supplying a mean daily consumption of up to 2 μg aflatoxin B1per kg body-weight. No histological changes attributable to aflatoxicosis were discovered in any of the organs from the monkeys receiving these quantities of aflatoxin.2. Few monkeys survived for more than a month or two when given a diet containing 1·8 μg aflatoxin B1per g, which provided about 50 μg aflatoxin B1per kg body-weight per day.3. No depression in growth rate nor effect on health was noted in those monkeys which survived on diets containing 1·8 μg aflatoxin B1, nor in any of the other monkeys.4. Histological changes were observed in the livers of all monkeys receiving the diet containing 1·8 μg aflatoxin B1per g for more than a month or two, but no abnormalities related to aflatoxicosis could be detected in any of the other organs, except for minor changes in the kidneys of two monkeys.5. No tumours were seen in any of the monkeys, even in those surviving for 3 years on diets providing 1·8 μg aflatoxin B1/g. Thus, no conclusions can be drawn from this work as to the carcinogenicity of aflatoxin in monkeys (still less in man), because the animals were young and little is known of the duration of exposure required to demonstrate carcinogenicity in this species.


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