The effect of level of environment on sex differences in pre-weaning growth rate in beef cattle

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.

1978 ◽  
Vol 56 (2) ◽  
pp. 298-306 ◽  
Author(s):  
Albert W. Franzmann ◽  
Robert E. LeResche ◽  
Robert A. Rausch ◽  
John L. Oldemeyer

A total of 1329 Alaskan moose (Alces alces gigas) were measured for total length, 1340 for chest girth, 1317 for hind foot, 618 for shoulder height, and 1219 for ear length. Five hundred and four moose were weighed. These data were classified by sex, age, month sampled, and location. Growth rates were plotted and discussed. No morphometric differences were detected by sex and location classifications up to age 36 months. Location differences were detected which corresponded to general condition, productivity, and condition related blood parameters of the populations. Seasonal weight patterns demonstrated increases from 21 to 55% from spring to late fall. Measurements, particularly total lengths, were better indicators of growth rate than were weights. All body measurements were significantly correlated with weight: total length, r (correlation coefficient) = 0.94; chest girth, r = 0.90; shoulder height, r = 0.87; and hind foot, r = 0.81. Combined sex regression equations were derived because the slight differences between the male and female regression lines were unimportant in field application. These regression equations were as follows: weight (kilograms) = −239.7 + 2.07(total length); weight (kilograms) = −245.3 + 3.14(chest girth).


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.


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.


1981 ◽  
Vol 21 (109) ◽  
pp. 172 ◽  
Author(s):  
KD Atkins ◽  
AR Gilmour

The growth to slaughter and carcase characteristics of purebred and crossbred lambs from five ewe breeds were compared in an experiment in 1971 and 1972 at Temora Agricultural Research Station. The ewe breeds were a Border Leicester x Merino fixed halfbred (BLM), Corriedale, Polwarth, a South Australian strong wool (SA Merino) and a medium wool Peppin strain of Merino. In each year, ewes of each breed were joined either to their own breed of ram or to Dorset Horn rams. The analysis used tested whether differences between ewe breeds in crossbred performance were halved compared with the differences between ewe breeds in purebred performances. The results supported this hypothesis for all characters measured. The largest breed effects on lamb performance were found for growth rate. Compared with the overall mean, the growth rates to weaning for purebred lambs were 118%,102%, 90%, 99% and 91% 10 for the BLM, Corriedale, Polwarth, SA Merino and Peppin Merino, respectively. The deviations from 100% for crossbred lambs were halved. Differences between breeds for carcase traits were estimated at the same carcase weight. South Australian Merino lambs had a lower dressing percentage than lambs from .the other breeds. Polwarths had the greatest depth of fat at the 12- 13th rib. Skins from Merino lambs had shorter staples and higher visual counts than skins from the other breeds. However, it was concluded that breed differences in carcase and skin characters, independent of carcase weight, were of little value in an economic comparison of the breeds for total productivity.


1994 ◽  
Vol 24 (10) ◽  
pp. 1997-2005 ◽  
Author(s):  
W.R. Remphrey ◽  
C.G. Davidson

Elongation of shoots in various crown locations, and of individual internodes and leaves of the leading shoot, were recorded at 2-day intervals throughout the 1991 growing season in four clones of Fraxinuspennsylvanica var. subintegerrima (Vahl) Fern. (green ash). Other trees were disbudded and pruned to a single leader. Using a logistic growth function, nonlinear regression equations were generated and parameter estimates were used to determine maximum growth rates. Terminal leading shoots had a longer growth duration and a greater maximum growth rate than lateral shoots. The pruning treatment resulted in larger shoots, which grew 2–3 weeks longer and had a higher maximum growth rate. Leaf emergence occurred at regular intervals but the rate of emergence varied among clones. Leaf maximum growth rates were not significantly different among clones. Leaf size declined acropetally whereas internode length increased and then decreased. The longest leaves and internodes had the highest maximum growth rates. The size and maximum growth rates of putative preformed leaves were larger than putative neoformed leaves. As a shoot expanded, growth of one internode tended to cease during the linear phase of growth of its associated leaf and that of the succeeding internode.


PEDIATRICS ◽  
1975 ◽  
Vol 56 (1) ◽  
pp. 5-7
Author(s):  
William C. Heird ◽  
John M. Driscoll

In this month's Pediatrics another method for feeding small infants is described. Although the method per se (i.e., intravenous supplementation of tolerated oral feedings) has been used frequently over the past few years, the present application is the first by which intrauterine growth rates with respect to weight, height, and head circumference have been achieved. The unique feature of the current application of the method is inclusion of an intravenously administered fat preparation as part of the nutrient infusate. The impressive growth rates were achieved without the use of central venous catheters with their attendant complications and without the use of indwelling intragastric or intraintestinal tubes. Several aspects of this interesting paper require comment. First, despite the fact that achievement of intrauterine growth rates postnatally has been the goal of neonatologists for a number of years, such a growth rate has never been shown to be beneficial. In fact, it can be argued that infants who are gaining weight, regardless of how slowly, are receiving adequate nutrients to meet on-going metabolic requirements and are not undergoing a net breakdown of endogenous nutrient stores. Furthermore, a number of changes in body composition (e.g., loss of body water) occur postnatally and these changes make a continued intrauterine growth rate almost impossible out major changes in metabolism and/or metabolic requirements. Moreover, most of the weight increase during the last trimester is fat which, perhaps beneficial before birth, may actually be detrimental when deposited postnatally. The appropriateness of a continued intrauterme growth rate is particularly pertinent when it is achieved with an agent that has not been evaluated thoroughly in very small infants (i.e., an intravenous soybean oil [Intralipid]).


1979 ◽  
Vol 19 (99) ◽  
pp. 407 ◽  
Author(s):  
PP Cotterill ◽  
EM Roberts

A breed comparison involving 31 2 crossbred progeny of three breeds of sire (Poll Dorset, Suffolk, and Lincoln) and five breeds of dam (Dorset Horn x Merino, Border Leicester x Merino, South Australian Merino, and Peppin Merino) was made between 1973 and 1975 in the western Riverina of New South Wales. The lambs were fed a post-weaning feedlot ration at one of two levels and were slaughtered when they reached 35 kg liveweight. Characters measured were: pre-weaning and postweaning growth rate, dressing percentage, carcase length, carcase leg length, kidney + pelvic fat weight, eye muscle length and depth, rib fat depth, and leg + loin fat and muscle percentage. Carcase characters were adjusted to a constant carcase weight. Important breed differences were those associated with rib fat depth and growth rate. The Suffolk- BL x M cross had high pre-weaning and post-weaning growth rates, but BL x M dams produced lambs with greater rib fat depths. The Suffolk-DH x M and Suffolk-DR x M crosses represented the best compromise between rib fat depth and growth, but their post-weaning growth rates were substantially less than the Suffolk-BL x M. These breed differences for rib fat depth and growth rate were not dependent on the level of post-weaning nutrition.


2010 ◽  
Vol 26 (4) ◽  
pp. 433-443 ◽  
Author(s):  
Jimena Forero-Montaña ◽  
Jess K. Zimmerman ◽  
Jill Thompson

Abstract:Dioecious plants often exhibit male-biased sex ratios and sexual differences in life history traits such as plant size, growth rate and frequency of flowering, which arise from the different costs of reproduction for male and female plants. In tropical dioecious species sexual differences in reproductive costs have been demonstrated for several subcanopy species, but few canopy dioecious trees have been studied. We recorded the sexual expression of c. 2600 trees of Cecropia schreberiana and Dacryodes excelsa, two canopy dioecious species, during several censuses over 2 y in a 16-ha plot located in ‘subtropical wet forest’ in the Luquillo Mountains, Puerto Rico. There were similar numbers of male and female trees of C. schreberiana but D. excelsa had a female-biased population. Cecropia schreberiana showed no differences in male and female diameter distributions or growth rates, suggesting that reproductive maturation and longevity are similar for both sexes. This lack of differences in size and growth rate in C. schreberiana may result from mechanisms to compensate for the higher cost of reproduction in females, no resource limitation related to its pioneer life-history, or similar male and female reproductive costs. In contrast, D. excelsa males were larger than females, probably because males grow slightly faster than females. This sexual difference in D. excelsa may reflect a higher cost of reproduction in females than in males. Spatial segregation of males and females into different habitats is not common in tropical forest and neither C. schreberiana nor D. excelsa males and females exhibited significant spatial segregation. The contrasting results for these two canopy species reflect their different life history strategies in this hurricane-affected forest.


Behaviour ◽  
1972 ◽  
Vol 42 (1-2) ◽  
pp. 1-7 ◽  
Author(s):  
H.H. Swanson ◽  
A.P. Payne

AbstractWeanling male and female golden hamsters were caged in matched-weight pairs on removal from their mothers. There were pairs of littermates and non-littermates of each sex. One partner of each pair was dyed on the chest with a black commercial hair-dye. Over 20 days, dyed animals of both sexes had a significantly higher growth rate than their untreated partners. In observations carried out between days 10-20 of the test period, dyed animals were found to be aggressively dominant over their untreated partners, and showed more aggressive behaviour. It is suggested that the growth of untreated animals was inhibited as a "stress" response either to the presence of the supra-normal threat stimulus, or to the aggressive relationship which resulted from it.


2017 ◽  
Vol 13 (6) ◽  
pp. 63 ◽  
Author(s):  
Mohammad Rafiqul Islam ◽  
Ishraque Bin Shafique ◽  
Kowshikur Rahman ◽  
Arafat Haque

This study was conducted on a group of male and female students of age range of 18-25 years. In this paper it is tried to find out a correlation between height and weight of male and female students. Then the simple regression equations of weight on height are fitted for both for male and female students. A total of 639 students of different departments of BRAC University, Dhaka, Bangladesh in the spring semester of 2016 are participated in this survey. Body Mass Index (BMI) of the students was calculated to compare the health status of male and females students. It is found that that the most of the students (males and females) have the normal weight. It is interestingly noticed that the higher percentage (34.18%) of males are overweight than the females; whereas the females (13.33%) are more than double in underweight than their male’s counterpart (5.93%). The correlation between height and weight of male students is calculated as 0.435 (Pearson’s coefficient of correlation). On the other hand the correlation between height and weight of female students was 0.319. From the t tests, it is proved that the both the coefficients of correlation are highly statistically significant (p-value<0.01). From the simple regression equations of weight on height, it is found that the both for male and female students the effect of height on weight is almost same. It is also found that the effect of height on weight both for male and female students is highly significant (p-value<0.01).


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