Physiological consequences of nighttime temperature for a tropical, herbivorous lizard (Cyclura nubila)

1986 ◽  
Vol 64 (4) ◽  
pp. 836-840 ◽  
Author(s):  
Keith A. Christian

Hatchling Cuban iguanas (Cyclura nubila) were reared for 38 weeks under three experimental conditions: nighttime temperatures of 15, 25, and 35 °C. All groups experienced a temperature of 35 °C during the day, and all were given food and water ad libitum. Growth rate (in terms of mass and length) increased with increasing nighttime temperature. The iguanas held at constant 35 °C were also more robust (defined as mass/length); this difference was not explained by the amount of fat. Passage time of food through the gut was shorter for the constant temperature group, which also consumed more food per day. There was no difference in digestive efficiency among groups, and the differences in growth rates were a result of the differences in food consumption. Constant temperature was apparently not detrimental for this tropical, herbivorous lizard. More data are required before useful generalizations concerning voluntary hypothermia in reptiles can be made.

1980 ◽  
Vol 30 (2) ◽  
pp. 307-310
Author(s):  
R. V. Large

ABSTRACTSoay ewes were mated to a Soay or a Dorset Down ram. Live-weight changes of the ewes, birth weights, growth rates and carcass production of the lambs were recorded, and the food consumption of the ewes and lambs was measured. The use of the Dorset Down ram resulted in significantly heavier birth weights, higher growth rates and heavier carcasses. Under conditions of good nutrition the Soay ewes proved to be capable of carrying very high foetal burdens and it was estimated, from lamb live-weight gains, that they produced a large quantity of milk, relative to their size, particularly when crossed with the Dorset Down ram.


1996 ◽  
Vol 11 (5) ◽  
pp. 1114-1119 ◽  
Author(s):  
A. Endo ◽  
H. S. Chauhan ◽  
Y. Nakamura ◽  
Y. Shiohara

Y1Ba2Cu307−x (Y123) crystals were grown by two different methods, the constant undercooling solidification and the continual cooling method, with top seeding by Sm123 seed crystals in order to investigate a relationship between undercooling (ΔT) and a growth rate (R). The crystals of Y123 with a sharp faceted interface, which consisted of {100} and {001} faces, grew epitaxially from the seed. It was found that the growth rates of {100} face (Ra) and that of {001} face (Rc) showed an increasing trend with increasing ΔT, and Rc was faster than Ra within these experimental conditions, ΔT < 20 K. The relation between R and ΔT follows the parabolic equation, viz. Ra ∝ ΔT1.9 and Rc ∝ ΔT1.3 for {100} and {001} faces, respectively. The simulated crystal size using the R and ΔT relations obtained from the constant undercooling method showed good agreement with experimental data by the continual cooling.


1976 ◽  
Vol 16 (81) ◽  
pp. 452
Author(s):  
MF Sharkey ◽  
RW Hodge ◽  
IF Davis ◽  
B Bogdanovic

Hay and silage treated with formaldehyde were compared with untreated hay and silage during in vivo studies of digestibility, and in growth studies where the forages were fed with and without barley to 6-month-old crossbred lambs. In the growth study there were 20 treatment groups (four forage types offered ad libitum x five barley levels 0, 100, 300, 500 and ad libitum g day-1). Sheep were fed for 6 and 12 weeks for groups fed silage and hay respectively following which animals were slaughtered. On a digested basis, barley contributed from 0 to 76 per cent of digested energy intake. Lamb growth rate varied between 0 and 150 g day-1 and was linearly related to intake of digested DM. Growth rates were above 100 g day-1 where barley constituted 60 to 70 per cent of this intake. Silage and hay with digestibilities of 62 to 65 per cent barely maintained sheep liveweights when fed as a sole diet. The sheep ate more hay than silage and treating the forage with formaldehyde did not significantly increase intake or growth rate.


1978 ◽  
Vol 5 (2) ◽  
pp. 131 ◽  
Author(s):  
DA Ivory ◽  
PC Whiteman

Cenchrus ciliaris, Chloris gayana, Panicum maximum var, trichoglume, Panicum coloratum var. makarikariense and Pennisetum clandestinum were grown in two experiments in controlled environments, each experiment having all possible day/night temperature combinations of (1) 10, 20, 30, and 40°C and (2) 15,25, 30 and 35°C. Both day and night temperatures significantly affected growth in all species. Growth was greatly restricted by constant temperatures of 10 and 15°, while maximum growth rates occurred at 29-35°C day temperatures with 26-30°C night temperatures. At optimum or supra-optimum temperatures a diurnal variation in temperature gave higher growth rates than a constant temperature for the same daily mean. By contrast, at suboptimum temperatures a constant temperature gave the highest growth rates and growth rate was decreased as the diurnal variation about a given daily mean temperature was increased. Mathematical functions relating the growth of each species to day and night temperature and maximum growth rate at optimum temperatures were developed. The effect of temperature on relative growth rate (Rw) was mediated through its effect on net assimilation rate (EA). Night temperature was found to affect Rw and EA independently of day temperature and therefore a prehistory effect of night temperature on photosynthesis in the subsequent day was indicated. Temperature had significant effects on tillering in P. maximum and P. clandestinum but had little effect in C. gayana, C. ciliaris and P. coloratum. The optimum temperatures for leaf growth and leaf area development in C. ciliaris and C. gayana were higher than the optimum temperatures for growth of the whole plant, while optimum temperatures for stem growth were lower. In P. maximum, P. coloratum and P. clandestinum, optimum temperatures for all growth components were similar. Differences between temperate and tropical grasses in morphological reaction to temperature are discussed.


1973 ◽  
Vol 13 (63) ◽  
pp. 360
Author(s):  
J Clark ◽  
JI Watts

Forty, Friesian x Jersey bull calves were fed diets comprising factorial combinations of milk, either whole (4.0 per cent fat) or skimmed (0.1 per cent fat) milk, fed at the rate of 4.5 kg day-1 until the calves were ten weeks old, with crushed barley at four levels from two to 18 weeks of age. The four levels of barley were 0, 25, 50 and 75 per cent of the dry matter intake of the calves. The calves had access to hay ad libitum throughout the experiment. The restricted quantities of skimmed milk fed to the calves did not support rapid gains in liveweight, even when supplemented with high levels of barley. The addition of barley to the diet of the calves reared on whole milk produced no response in terms of growth rate (0.54 kg day-1). However, the calves reared on skimmed milk had greater growth rates when their diet contained 25 per cent barley than with no barley, 0.36 kg day-1 and 0.28 kg day-1 respectively. Further additions of barley did not produce additional responses in growth rate.


1999 ◽  
Vol 68 (3) ◽  
pp. 477-485 ◽  
Author(s):  
P. J. Blanchard ◽  
M. Ellis ◽  
C. C. Warkup ◽  
B. Hardy ◽  
J. P. Chadwick ◽  
...  

AbstractThe influence of plane of nutrition and diet on the eating quality of fresh pork was investigated in a study involving 721 animals. Boars and gilts of three genotypes (0, 0·25 and 0·50 Duroc inclusion level) were reared from 30 to 90 kg on seven feeding regimens (combinations of diet formulation and feeding level) to achieve different rates of lean and fat tissue growth during two growth periods (30 to 60 or 75 kg; 60 or 75 kg to 90 kg), respectively. A diet of conventional energy and protein (CEP, 14·2 MJ/kg digestible energy, 205 g/kg crude protein, 10 g/kg lysine) was given using combinations of ad libitum and restricted feeding to produce six treatment groups with variation in lean and fat growth rates. An additional treatment group was given food ad libitum on a higher energy and lower protein diet (HELP, 14·7 MJ/kg digestible energy, 166 g/kg crude protein, 7·0 g/kg lysine) between 30 and 90 kg. Dissected carcass composition at 90 kg was predicted from equations based on P2 fat depth, which were developed from full-side and ham joint dissections on sub-samples of animals. Representative sub-samples of animals were dissected at start (30 kg) and at interim weights (60 or 75 kg) to allow lean and subcutaneous fat growth rates to be calculated for all or parts of the growth period. The feeding regimes produced substantial variation in live-weight gain (DLWG) (744 to 914 g/day) and lean tissue growth rate (LTGR 345 to 417 g/day) and subcutaneous fat growth rate (SFGR 81 to 97 g/day), between 30 and 90 kg, and in longissimus dorsi intramuscular fat content (10·37 to 23·87 g/kg). Pigs given the HELP diet had the highest intramuscular fat and the best eating quality. Pigs offered the CEP diet ad libitum throughout the growth period produced more tender but less juicy meat than those given food restrictedly (0·8 or 0·9 of ad libitum). The correlations between DLWG, LTGR and SFGR for the whole or parts of the growth period and sensory characteristics, although often positive, were generally low, suggesting weak relationships.


1983 ◽  
Vol 37 (1) ◽  
pp. 137-140 ◽  
Author(s):  
J. A. Woolliams ◽  
G. Wiener

ABSTRACTLambs, 8 weeks of age, the offspring of sires of the Scottish Blackface, East Friesland, Finnish Landrace, Suffolk and Texel breeds mated to Scottish Blackface females as a common maternal breed were fed ad libitum on a concentrate containing barley and fish meal for 14 weeks. Live weight and food intake were measured at intervals of 2 weeks.Live-weight gain varied between sire breeds, Suffolk crosses having the greatest growth rate and the Blackface lambs the least, but there were no significant differences in their food conversion ratios. Food intakes were compared with those predicted by two methods. When the only criteria for prediction were live weight and the metabolizability of the diet the prediction was poor, whereas very accurate agreement was found when the criteria for prediction included consideration of the changes in energy efficiency with food intake and with maturity.


Author(s):  
M.H. Davies ◽  
E.M. Thomas

Scottish red deer research has defined under hill and upland conditions the relationship that exists between the winter growth rate of stag calves and their performance at grass the following summer (Adam, 1986; Blaxter et al, 1988). With the increasing movement of stag calves to the lowlands of England and Wales, and an expansion in finishing units in these areas, such a relationship needs re-defining to take account of the differences in climate, length of growing season and grass supply. This trial investigates the effect of two growth rates over winter on the overall performance of stag calves, both on hay and silage based rations, under lowland conditions.Forty red deer stag calves approximately 4 months of age and weighing 40 kg liveweight were purchased from Scotland in September 1988. They were housed in one group and fed a common ration of ad libitum hay + 1 kg of a proprietary 18% CP compound per head per day from arrival on 26 September until 9 November 1988.


1997 ◽  
Vol 54 (7) ◽  
pp. 1532-1541 ◽  
Author(s):  
W Aboul Hosn ◽  
P Dutilleul ◽  
D Boisclair

We used spectral analysis to investigate the periodic components of relative growth rates (on a mass and length basis) in two groups of six\b young-of-the-year brook trout (Salvelinus fontinalis). Fish were measured every 2 days for 25 days according to a repeated measures design in time. The predominant frequency components were estimated at the end of a stepwise procedure involving the analysis of the multifrequential periodogram. We found mainly two superimposed periodic components that resulted in short rhythms; these had a period of about 5 and 10 days for the growth rate in mass and of about 4 and 6 days for the growth rate in length (R2 = 91% for mass and 90% for length, both including an autocorrelation term). Repeatability of rhythms was assessed by ANOVA of the finite Fourier transform, which showed that the two groups of fish reared under the same experimental conditions exhibited growth rhythms that were not significantly different from each other. On that basis, we present a harmonic model which predicts short-term variation in growth rate of brook trout in mass (R2pred = 0.73, with an autocorrelation term) and in length (R2pred = 0.72).


1966 ◽  
Vol 66 (1) ◽  
pp. 67-85 ◽  
Author(s):  
ST C. S. Taylor ◽  
G. B. Young

In an experiment to investigate the interrelationships of genetics and nutrition in the growth of cattle up to 2 years of age, five monozygotic and six dizygotic Ayrshire twin heifers were reared under close nutritional control on an all cubed diet.Two control systems were used. Some animals were fed similar amounts of food, and differences in growth rate and efficiency examined while others were made to grow alike and differences in food consumption and efficiency examined. Overall, similarly fed animals had similar growth rates and efficiencies and similarly grown animals similar food intakes and efficiencies. Variation in growth, food consumption and efficiency was much less than in an ad lib. feeding system.


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