Comparative breed studies of beef cattle. I. Changes in body weight

1963 ◽  
Vol 14 (6) ◽  
pp. 882 ◽  
Author(s):  
NM Tulloh

A comparative growth study was made of Hereford, Aberdeen Angus, and beef Shorthorn cattle reared and kept together throughout their lives on irrigated perennial pastures at the Metropolitan Farm, Werribee, Vic. Records of body weight as a function of age were obtained on 404 Hereford, 172 Aberdeen Angus, and 127 Shorthorn cattle, representing cattle born in 1955, 1957, 1958, 1959, and 1960. At birth, male calves were significantly heavier than females, and Hereford calves were significantly heavier than Shorthorn and Aberdeen Angus calves, the birth weights of Shorthorn and Aberdeen Angus calves being similar. Up to the age of 5 years, the younger and lighter 2-year-old cows produced lighter calves than cows which were both older and heavier. At weaning age (9.5 months) steers were significantly heavier than heifers. Herefords were significantly heavier than Aberdeen Angus in two years out of three; and in one year out of three, Herefords were significantly heavier than Shorthorns. Shorthorns were significantly heavier than Aberdeen Angus in one year out of three. When the steers were finally weighed off grass at the mean age of either 20 months (1958, 1959, and 1960 cattle) or 25 months (1957 cattle), Herefords were significantly heavier than Aberdeen Angus in four successive years, and in one year out of four the Herefords were significantly heavier than Shorthorns. In three years out of four, Shorthorns were significantly heavier than Aberdeen Angus. Breed differences between the mean weights of breeding cows were not significant and, up to the age of 5 years, as breeding cows grew older they became heavier. Body weight growth curves indicated that the cattle experienced a severe check in growth during the winter months (June, July, August). At other times of the year, growth rates were satisfactory. Cattle born in some years grew better than cattle born in others. This was thought to be due partly to differences between years in the quality and quantity of pasture available, even though the pastures were irrigated. Average absolute and average relative growth rates were calculated for the 1957 and 1958 steers before and after weaning. Breed differences in absolute growth rates before weaning were not statistically significant, but after weaning, rates were significantly the highest for Herefords in both years. The breed differences in average relative growth rates were in the same direction as those for absolute growth rates. However, the pre-weaning relative growth rate of Shorthorns was significantly higher than those of the other breeds among the 1957 steers. When due allowance was made for the smaller size of Aberdeen Angus steers at birth and at weaning, the relative growth rates of this breed were less than those of the other breeds. Absolute and relative growth rates were higher for all breeds before weaning than afterwards. This was mainly a reflexion of low post-weaning growth rates during the winter months. Rank correlation coefficients between birth weight and weight at subsequent ages were low and variable in different breeds and in different seasons. However, coefficients calculated between subsequent ages, beginning at weaning age, were generally highly significant. The breed and sex differences presented in this paper have been compared with the limited data from the literature and, in general, the results are similar.

2016 ◽  
Vol 24 (1) ◽  
pp. 155-159 ◽  
Author(s):  
Kei Ando ◽  
Shiro Imagama ◽  
Zenya Ito ◽  
Kazuyoshi Kobayashi ◽  
Hideki Yagi ◽  
...  

OBJECT Little is known about the progression of spinal schwannomas. The aim of this study was to determine the natural progression of spinal schwannomas and establish the risk of tumor growth. METHODS This study retrospectively analyzed data from 23 patients (12 men and 11 women, 40–89 years old) with schwannomas detected by MRI. The mean follow-up period was 5 years (range 2–10 years). The absolute and relative growth rates of the tumors were calculated. RESULTS The average tumor size was 1495 mm3 at the initial visit and 2224 mm3 at the final follow-up. The average absolute growth rate was 139 mm3 per year, and the average relative growth rate was 5.3% per year. Tumors were classified into 3 groups based on enhancement patterns: isointense/hyperintense (iso/high; 11 cases), rim enhancement when enhancement was peripheral (high/rim; 5 cases), and heterogeneous/heterogeneous (hetero/hetero; 7 cases) based on Gd-enhanced T2-weighted MRI. The average absolute growth rates of the 3 lesion groups were 588 mm3, 957 mm3, and 3379 mm3, respectively (p < 0.01). CONCLUSIONS Although the tumors classified as iso/high and high/rim on T2-weighted Gd-enhanced MR images were small and grew very little, most tumors with hetero/hetero classification increased in size. Hetero/hetero-type tumors should be followed closely and may require surgery.


2017 ◽  
Vol 65 ◽  
pp. 16-21 ◽  
Author(s):  
Madhu Awasthi ◽  
Pragya Gupta ◽  
Farah Bano ◽  
Mohammad Serajuddin

Juvenile of Trichogaster lalius was reared under three photoperiod conditions (0L:24D, 12L:12D, 16L:08D) for 60 days to examine the growth performance under laboratory conditions. The maximum growth was observed in the juvenile of T. lalius exposed to 16:00 hrs. light. The mean body weight of different groups of juvenile fish exposed to different light conditions were significantly different (p<0.05) from each other which was observed from 20thday of the experiment. The absolute, specific, and relative growth rates were found to be maximum in the group exposed to 16:00 hrs. light duration. The present study indicated that 16:00 hrs. light duration was considered to be better for the growth of juvenile of T. lalius under controlled condition.


1986 ◽  
Vol 64 (1) ◽  
pp. 233-237 ◽  
Author(s):  
Susan R. Singer

Growth is the major parameter used to assess novel phenotypes derived from plant tissue cultures. Any quantitative analysis of growth must have an explicit rational basis. Frequently this criterion is not met. For example, the calculation (W2 − W1)/W1(W1 = initial weight; W2 = final weight) approximates neither linear nor exponential growth. Yet, it is a common method of analysis, as is the related calculation W2/W1. When absolute growth values provide insufficient information, meaningful relative growth rate equations can be utilized. Relative growth rates should be evaluated as ln (W2/W1)/(t2 − t1) for t = time, thereby yielding a constant growth rate for exponentially growing cell lines. Linear growth (root growth, for example) can be approximated by 2(W2 − W1)/((W1 + W2)(t2 − t1)). All methods of analysis we have encountered assume that relative growth at a given instant depends on total mass. The possibility exists that growth may actually be proportional to mass raised to some power less than one. For example, growth could be limited to a thin outer shell of a spherical callus. Then the relative growth rate would equal 3(W21/3 − W11/3)/(t2 − t1). Data can be seriously distorted when inappropriate calculations are used. Such distortions are exacerbated when comparisons are made. In all cases an adequate assessment of growth kinetics for each cell line and each treatment is essential.


Botany ◽  
2020 ◽  
Vol 98 (8) ◽  
pp. 469-478
Author(s):  
Diane Auberson-Lavoie ◽  
Mark Vellend

Models of ecological responses to climate warming predict species’ migration towards higher latitudes or elevations. However, models often neglect nonclimatic factors, such as herbivory, which could slow down or prevent geographic range expansion. A previous study in Mont Mégantic National Park (Quebec) found that in one year (2016), browsing by white-tailed deer on Trillium erectum L. was substantially higher at high elevations than low elevations. Under the hypothesis that deer herbivory could limit the upper elevational range expansion of T. erectum, here we ask (i) whether herbivory increased with elevation during two additional years (2017 and 2018), (ii) whether the rate of deer visitation increases with elevation, and (iii) whether the effect of herbivory on relative growth rates increases with elevation. Contrary to the earlier study, we did not find a significant trend of herbivory with elevation, although there was a weak positive relationship between deer visitation and elevation. We found a strong negative impact of browsing on relative growth rates, but the magnitude of this effect did not vary with elevation. Our results thus do not support the hypothesis that herbivory limits the range of T. erectum at high elevation, but herbivory could have a negative impact on populations in general if the browsing rate remains high.


1991 ◽  
Vol 8 (4) ◽  
pp. 160-165 ◽  
Author(s):  
David G. Simpson

Abstract Interior spruce (white or Englemann spruce) was grown in containers having volumes of 45 to 120 cm³ and at nursery densities of 64 to 1111 seedlings/m². In three experiments, seedlings grown at greater densities had decreased shoot and root weights, decreased stem diameters, and in some cases greater shoot heights. Seedlings grown in containers with greater volumes were larger. Interaction between container volume and growing density was such that the effect of container volume was only evident at growing densities less than 568 seedlings/m². Maximum crop biomass for interior spruce was found to be 3 kg/m². Crop uniformity decreased as maximum crop biomass was approached. The greatest number of uniformly larger (5 to 6 g) seedlings are produced at growing densities of 500 to 600 seedlings/m². Growth of outplanted seedlings suggested larger seedlings had greater field growth, but the mean relative growth rates (RGR) of different sized seedlings were not affected by nursery growing densities. The results reported support the view that larger planting stock has apparently greater growth not because of greater growth rates, but because of larger initial size and the compounding effect of growth. North. J. Appl. For. 8(4):160-165.


Zygote ◽  
2003 ◽  
Vol 11 (2) ◽  
pp. 101-106 ◽  
Author(s):  
María Altamirano ◽  
Antonio Flores-Moya ◽  
Ralph Kuhlenkamp ◽  
Félix L. Figueroa

Sensitivity to ultraviolet (UV) radiation (UV-A, λ = 315-400 nm; plus UV-B, λ = 280-315 nm) of zygotes of the brown alga Fucus serratus L. (Phaeophyta) has been assessed through effects on growth of developing germlings. Different stages of development were distinguished by considering 5 h periods of time after fertilisation. Both the stage of the zygote and the UV radiation condition significantly affected growth of developing germlings. The negative response of growth rate of early stages of the zygotes to UV radiation seemed to be caused by UV-B rather than UV-A radiation, as the lowest relative growth rates were always estimated for germlings developed from zygotes irradiated with UV-B radiation. As regards the stage of the zygote, those germlings that developed from zygotes irradiated at 5-10 h after fertilisation showed the strongest inhibition of growth compared with the other stages. These results point to polarisation as the most UV-sensitive process during the first 24 h of the development of the zygote. A non-linear relationship between the developmental stage of the zygote and the sensitivity to UV radiation is suggested.


2008 ◽  
Vol 38 (2) ◽  
pp. 257-267 ◽  
Author(s):  
D. Bruce Campbell ◽  
Chuck E. Bulmer ◽  
Melanie D. Jones ◽  
Leanne J. Philip ◽  
Janusz J. Zwiazek

Rehabilitation of skid trails, temporary roads, and log landings is required for many harvested sites in British Columbia; however, more information is needed regarding practical methods to return these access areas to productive forest. Lodgepole pine ( Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) seedlings (1 + 0) were planted into (i) fully rehabilitated landings (burn-pile debris and topsoil incorporated), (ii) tilled landings, and (iii) unprepared portions of the adjacent cutblock. After two seasons of growth in the field, seedlings planted on fully rehabilitated landings were 38% larger, more robust, and exhibited 44% greater absolute growth and 22% greater relative growth rates, than seedlings planted in the adjacent cutblock. Seedlings planted on tilled landings were 33% smaller, and exhibited absolute growth rates 38% less, and relative growth rates 18% less, than seedlings planted in the adjacent cutblock. Seedlings planted in the cutblock exhibited higher ectomycorrhizal colonization rates. Our results indicate that tillage alone was not sufficient to fully rehabilitate these landings, but that incorporation of recovered topsoil and burn-pile debris produced an excellent growth substrate. This method, using materials found on site, can prevent a significant loss of land regenerating to productive second-growth forest.


1988 ◽  
Vol 18 (6) ◽  
pp. 710-717 ◽  
Author(s):  
J. T. Arnott ◽  
A. N. Burdett

Four types of western hemlock (Tsugaheterophylla (Raf.) Sarg.) nursery stock, differing in size, morphology, and root growth capacity were planted on a clear-cut forest site on Vancouver Island, British Columbia. The stock types were: (i) 1-year-old, plug-rooted seedlings raised in 36-cm3 containers; (ii) as (i) but transplanted to a bareroot nursery for 1 year; (iii) 1-year-old, bareroot seedlings raised in 1000-cm3 containers; (iv) as (iii) but raised in containers coated on the inside with copper paint to inhibit lateral root elongation upon contact with the container wall. Survival and growth of seedlings with and without fertilization at planting with 50 g of a slow-release (Nutricote®, 12-month release at 25 °C) N–P–K fertilizer were observed for 3 years. Neither stock type nor fertilizer had a statistically significant (P < 0.05) effect on seedling survival. At planting, plug seedlings were significantly (P < 0.01) shorter and smaller in stem volume than the other stock types. These differences were no longer evident by the end of the third growing season because of more rapid growth by the plug stock. The largest differences between the plugs and the other stock types in height and diameter relative growth rates occurred during the first growing season. Fertilization significantly (P < 0.01) increased height and stem volume relative growth rates of all stock types during the first growing season. During the third growing season fertilization had a significant (P < 0.01) negative effect on height, and diameter and stem volume relative growth rates of all stock types, but not on absolute rates. At the end of three growing seasons, fertilized trees remained significantly (P < 0.01) larger in all stock types than in the controls.


2021 ◽  
Vol 34 (1) ◽  
pp. 1-13
Author(s):  
M. O. Ozoje ◽  
S. O. Peters ◽  
S. I. Ojikuku

Individual growth curve parameters are suitable phenotypic variable for the assessment of growth course and early maturity. This study focused on the analyses of growth curves parameters of N’Dama cows derived from the Richarads growth function. Data consist of field records of weight measurements from birth to 36 months old of 98 N’Dama cows born and raised between 1992 and 1998. The coefficient of variation was moderately high in both the curve and predicted parameters except for point of inflation (m). The estimates of heritability for maturing traits ranged from 0.18 to 0.30. While those for body weights and growth traits ranged form 0.21 to 0.47. High correlation coefficients were observed between mature weight parameter (A) and body weight at 180 days. 365days and 550days of age. A negative relationship was observed between A and maturing rate index k,(0.51) and between A and all maturing parameters associated with stages of growth (degrees of maturity and relative growth rates). Sire variation was an important source of variation (P < 0.05) for all the parameters studies except for residual means squares (RMS). Year of birth was also a significant (P < 0.05), source of variation for A, K, RMS, degrees of maturity at 180days of age and the relative growth rates at 180days and 365 of age, while age of dam significantly (P < 0.05) affected the constant of integration b, the maturing rate index k, body weight and degree of maturity at 180days of age. Season of birth affected the point of inflation (m) RMS body weight at 180day and absolute growth rate at 365days of age. The interaction between year of birth and age of dam was significant (P < 0.05), affecting only the A and the K parameters


1969 ◽  
Vol 22 (4) ◽  
pp. 1077 ◽  
Author(s):  
PJ Pahl

Body weight growth of rats, bred and reared in small cages, occurs in two main stages, which overlap to a degree. During the first stage, when rats develop to maturity, all parts of the animal (e.g. head, body, limbs, tail) grow, resulting in high relative growth rates. During the second stage, one of post-maturity growth, there is an increase in body weight, unaccompanied by corresponding significant changes in such measures as limb and tail length. It is thought that the increase in body weight during the second stage is due to an increase in body fat; however, further experimentation is required to verify this contention.


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