Fleece growth in Australian cashmere goats. II. The effect of pregnancy and lactation

1993 ◽  
Vol 44 (5) ◽  
pp. 1023 ◽  
Author(s):  
WRL Kloren ◽  
BW Norton
Keyword(s):  
Growth Rate ◽  
Hair Growth ◽  
Growth Cycles ◽  
Rate Of Growth ◽  
Delayed Initiation ◽  
Pregnancy And Lactation ◽  
Cashmere Goats

Groups of Australian cashmere does were randomly assigned to December, March, July and September kidding groups in two successive years, and cashmere and hair growth was compared to does not kidding in each year. There was no significant (P > 0.05) effect of kidding time on cashmere growth rate. Kidding in December significantly (P < 0.05) delayed initiation of cashmere growth by around 2 weeks and occurred around February. Half of the does kidding in March failed to grow cashmere, and of the others, initiation date or rate of growth was not affected. Kidding in July advanced the cessation of cashmere growth to May compared with July in control does. Does kidding in September had cashmere growth cycles similar to those of control goats; however, fleece regrowth following shearing in June was significantly (P < 0.05) less. There were no consistent effects of kidding time on hair growth, but regrowth was significantly (P < 0.05) greater in the March kidding group following shearing in June.

A population birth-and-mutation process, I: explicit distributions for the number of mutants in an old culture of bacteria

1974 ◽  
Vol 11 (03) ◽  
pp. 437-444 ◽  
Author(s):  
Benoit Mandelbrot
Keyword(s):  
Growth Rate ◽  
Mutation Rate ◽  
Growth Rates ◽  
Random Variable ◽  
Mutation Process ◽  
Limit Condition ◽  
Rate Of Growth ◽  
Mathematical Techniques ◽  
First Time

Luria and Delbrück (1943) have observed that, in old cultures of bacteria that have mutated at random, the distribution of the number of mutants is extremely long-tailed. In this note, this distribution will be derived (for the first time) exactly and explicitly. The rates of mutation will be allowed to be either positive or infinitesimal, and the rate of growth for mutants will be allowed to be either equal, greater or smaller than for non-mutants. Under the realistic limit condition of a very low mutation rate, the number of mutants is shown to be a stable-Lévy (sometimes called “Pareto Lévy”) random variable, of maximum skewness ß, whose exponent α is essentially the ratio of the growth rates of non-mutants and of mutants. Thus, the probability of the number of mutants exceeding the very large value m is proportional to m –α–1 (a behavior sometimes referred to as “asymptotically Paretian” or “hyperbolic”). The unequal growth rate cases α ≠ 1 are solved for the first time. In the α = 1 case, a result of Lea and Coulson is rederived, interpreted, and generalized. Various paradoxes involving divergent moments that were encountered in earlier approaches are either absent or fully explainable. The mathematical techniques used being standard, they will not be described in detail, so this note will be primarily a collection of results. However, the justification for deriving them lies in their use in biology, and the mathematically unexperienced biologists may be unfamiliar with the tools used. They may wish for more details of calculations, more explanations and Figures. To satisfy their needs, a report available from the author upon request has been prepared. It will be referred to as Part II.

Effects of variations in dietary protein levels on hair growth and pelt quality in mink (Mustela vison)

2000 ◽  
Vol 80 (4) ◽  
pp. 633-642 ◽  
Author(s):  
Palle V. Rasmussen ◽  
Christian F. Børsting
Keyword(s):  
Protein Content ◽  
Dietary Protein ◽  
Protein Level ◽  
Hair Growth ◽  
Fibre Length ◽  
Hair Follicles ◽  
Protein Levels ◽  
Low Protein ◽  
Pregnancy And Lactation ◽  
Hair Fibre

The effect of different and shifting dietary protein levels on hair growth and the resulting pelt quality in mink was studied. Two groups of pastel female mink were fed either 59% (high protein, HP) or 40% (low protein, LP) of metabolisable energy (ME) from protein during pregnancy and lactation. Shortly after weaning, kits from females fed the LP diet were put on a new LP diet (21% protein of ME). Kits from females fed HP were randomly distributed to four experimental groups fed a new HP diet (34% protein of ME) and three of these groups were shifted to diets with 21% protein at different times during June until September. Skin biopsies were taken at 4, 6, 23 and, 29 wk of age. Histological techniques and computer-assisted light microscopy were used to determine the ratio of activity (ROA) of underfur and guard hairs, respectively, defined as the number of growing hairs as a percentage of the total number of hairs. The hair fibre length and thickness were determined by morphometric methods and correlated with fur properties of dried pelts judged by sensory methods. It was documented that 40% of ME from protein during pregnancy and lactation was sufficient for mink kits to express their genetic capacity to produce hair follicles. In males, a reduced protein level from the age of 15 wk or 22 wk until pelting disturbed moulting, indicated by a low ROA of underfur hairs at 23 wk, and consequently reduced the growth and development of the winter coat. A constantly low protein level from conception until the age of 29 wk did not disturb moulting, but led to a reduction of primeness and especially of the underfur length and fibre thickness of the winter coat. A low protein level from the age of 9 wk only reduced the thickness of the underfur fibres. Hair growth, final fur volume, and general quality of the winter coat of males were influenced negatively and to the same degree in all groups fed the LP diet in part of the growth period. The number of underfur hairs per area (hair density) of the winter coat was not influenced by the dietary treatment meaning that the protein content of 21% of ME in the LP diet was high enough for the mink to express its genetic capacity to develop hair follicles. However, this low protein content led to a reduction of hair fibre length and hair fibre thickness of the underfur. Overall, this study demonstrated that hair growth and hair properties in pelts are very dependent on the dietary protein supply in the period from 22 wk of age until pelting, irrespective of the supply in the preceding periods. Key words: Fur properties, hair fibres, nutrition, pelage, protein requirement

scholarly journals Protein utilization, growth and survival in essential-fatty-acid-deficient rats

1996 ◽  
Vol 75 (2) ◽  
pp. 237-248 ◽  
Author(s):  
Christiani Jeyakumar Henry ◽  
Amal Ghusain-Choueiri ◽  
Philip R. Payne
Keyword(s):  
Growth Rate ◽  
Dietary Protein ◽  
Essential Fatty Acids ◽  
Coconut Oil ◽  
Deficient Diet ◽  
Protein Utilization ◽  
Growth And Survival ◽  
Retarded Growth ◽  
Pregnancy And Lactation ◽  
The Relationship

AbstractThe relationship between essential fatty acids (EFA) deficiency and the utilization of dietary protein, growth rate and survival of offspring was investigated in rats during development and reproduction. EFA deficiency was induced by feeding a 200 g casein/kg-based diet containing 70 g hydrogenated coconut oil (HCO)/lkg as the only source of fat. The conversion efficiency of dietary protein was assessed as net protein utilization (NPU), using a 10 d comparative carcass technique. Consumption of the deficient diet during the 10 d assay period induced biochemical changes characteristic of mild EFA deficiency in humans (triene:tetraene 0·27 (SD 0·04) compared with 0·026 (SD 0·004) for wn-deficient controls), but there were no significant changes in growth rate or protein utilization. These variables were also unchanged when the deficient diet was fed for an additional 7 d before the assay, although triene: tetraene increased to 0.8 (SD 0·02). Feeding the deficient diet for 63 d before assay produced severe EFA deficiency (triene:tetraene 1.4 (SD 0·3) v. 0·036 (SD 0·005) for controls), a fall in growth rate (25% during assay period), and NPU (31.5 (SD 0·63) v. 39.0 (SD 0·93) for controls). These severely-EFA-deficient animals had a 30% higher fasting-resting rate of energy metabolism than that of age-matched controls. However, there was no change in the rate of endogenous N loss. Voluntary energy consumption was increased in animals fed on deficient diets, either with 200 g protein/kg, or protein free. The reduced efficiency of protein utilization could be entirely accounted for by the restricted amount of energy available for growth and protein deposition. Consumption of an EFA-deficient diet during pregnancy and lactation resulted in high mortality (11% survival rate at weaning compared with 79% for controls) and retarded growth in the preweaning offspring. It is concluded that animals are particularly sensitive to EFA deficiency during reproduction and pre- and post-natal stages of development. However, after weaning only severe EFA deficiency retarded growth, primarily through changes in energy balance.

scholarly journals Sectoral Volatility, Development, and Governance: A Case Study of Pakistan

2006 ◽  
Vol 45 (4II) ◽  
pp. 797-817
Author(s):  
Toseef Azid ◽  
Naeem Khaliq ◽  
Muhammad Jamil
Keyword(s):  
Growth Rate ◽  
Structural Change ◽  
Service Sector ◽  
Structural Changes ◽  
Agricultural Sector ◽  
Green Revolution ◽  
Rate Of Growth ◽  
Agriculture Industry ◽  
The Future

Development of overall economy of any country largely depends upon the characteristics of different prominent sectors such as agriculture, industry, services, etc. Sharp structural change in prominent sectors are experienced by the Pakistan’s economy during the last four decades, in which industrial and service sector have exhibited an extra ordinary rate of growth, while the agricultural sector did not shown that rate of growth which was experienced during the time of green revolution. Due to these structural changes in the prominent sectors volatility of growth rate has been experienced by the economy. To the extent that most of the recent volatility in growth rate of GDP can be attributed to the increasing share of the some volatility of the some prominent sectors, the analysis of their volatility can be useful in providing some enlightenment on the factors behind this phenomenon and its implications for the formulation of the policy in the future.

THE ACTION OF HORMONES ON SPONTANEOUS HAIR GROWTH CYCLES IN THE RAT

1964 ◽  
Vol 29 (2) ◽  
pp. 193-201 ◽  
Author(s):  
F. J. EBLING ◽  
ELIZABETH JOHNSON
Keyword(s):  
Hair Growth ◽  
Hair Follicles ◽  
Female Rats ◽  
Hair Length ◽  
Growth Cycles ◽  
Hormonal Effects

SUMMARY Hypophysectomy of, or administration of thyroxine to, male or female rats advances the activity of hair follicles in the ensuing wave of growth; administration of propylthiouracil retards it. The effects seem to be more marked in the dorsal and head regions than in the flank or belly. Propylthiouracil does not prevent the activation of the follicle induced by plucking of the club hair. It is suggested that the hormonal effects may be produced indirectly through the dermis. Hypophysectomy increased definitive hair length in females but not in males; thyroxine also produced a small increase and propylthiouracil a decrease which proved to be significant in females, but not in males.

The Relative Growth of Parts in Palaemon Carcinus

1930 ◽  
Vol 7 (2) ◽  
pp. 165-174
Author(s):  
M. A. TAZELAAR
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Linear Measurements ◽  
Relative Growth ◽  
Male And Female ◽  
Relative Growth Rates ◽  
Rate Of Growth ◽  
The Difference ◽  
Rates Of Growth

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.

QUANTITATIVE STUDIES OF HAIR GROWTH IN THE ALBINO RAT

1958 ◽  
Vol 16 (4) ◽  
pp. 351-359 ◽  
Author(s):  
ELIZABETH JOHNSON
Keyword(s):  
Hair Growth ◽  
Female Rats ◽  
Male Rats ◽  
Hair Length ◽  
Inhibitory Effects ◽  
Albino Rat ◽  
Rate Of Growth ◽  
Quantitative Studies ◽  
Reduced Rate ◽  
Second Wave

SUMMARY 1. Spaying of female rats aged 7 weeks accelerated the passage of the second wave of hair growth. Longer hairs were produced as a result of faster growth, and the rate of loss of dead or 'club' hairs [cf. Johnson, 1958] was increased. 2. Oestradiol implanted into spayed females delayed the initiation and passage of the wave. Shorter hairs were produced by a reduced rate of growth, and loss of club hairs was inhibited. 3. Castration of male rats aged 7 weeks accelerated the passage of the second wave of growth, and implantation of testosterone slowed it down. Testosterone had no effect on the definitive length of hair produced or on the rate at which club hairs were lost. 4. Oestradiol implanted into castrated males produced the same effects as in spayed females except that it had no effect on the time of initiation of the wave. 5. Combined implantation of testosterone with oestradiol into castrated males did not off-set the inhibitory effects of the oestradiol on hair length or rate of loss of club hairs, but may have slightly speeded the hair wave.

Implications of rRNA Operon Copy Number and Ribosome Content in the Marine Oligotrophic Ultramicrobacterium Sphingomonassp. Strain RB2256

1998 ◽  
Vol 64 (11) ◽  
pp. 4433-4438 ◽  
Author(s):  
Fitri Fegatella ◽  
Julianne Lim ◽  
Staffan Kjelleberg ◽  
Ricardo Cavicchioli
Keyword(s):  
Growth Rate ◽  
Copy Number ◽  
Heterotrophic Bacteria ◽  
Single Copy ◽  
Rrna Operon ◽  
Limiting Factor ◽  
E Coli ◽  
Rate Of Growth ◽  
Rates Of Growth ◽  
Low Rate

ABSTRACT Sphingomonas sp. strain RB2256 is a representative of the dominant class of ultramicrobacteria that are present in marine oligotrophic waters. In this study we examined the rRNA copy number and ribosome content of RB2256 to identify factors that may be associated with the relatively low rate of growth exhibited by the organism. It was found that RB2256 contains a single copy of the rRNA operon, in contrast to Vibrio spp., which contain more than eight copies. The maximum number of ribosomes per cell was observed during mid-log phase; however, this maximum content was low compared to those of faster-growing, heterotrophic bacteria (approximately 8% of the maximum ribosome content of Escherichia coli with a growth rate of 1.5 h−1). The low number of ribosomes per cell appears to correlate with the low rate of growth (0.16 to 0.18 h−1) and the presence of a single copy of the rRNA operon. However, on the basis of cell volume, RB2256 appears to have a higher concentration of ribosomes than E. coli (approximately double that of E. coli with a growth rate of 1.5 h−1). Ribosome numbers reached maximum levels during mid-log-phase growth but decreased rapidly to 10% of maximum during late log phase through 7 days of starvation. The cells in late log phase and at the onset of starvation displayed an immediate response to a sudden addition of excess glucose (3 mM). This result demonstrates that a ribosome content 10% of maximum is sufficient to allow cells to immediately respond to nutrient upshift and achieve maximum rates of growth. These data indicate that the bulk of the ribosome pool is not required for protein synthesis and that ribosomes are not the limiting factor contributing to a low rate of growth. Our findings show that the regulation of ribosome content, the number of ribosomes per cell, and growth rate responses in RB2256 are fundamentally different from those characteristics in fast-growing heterotrophs like E. coliand that they may be characteristics typical of oligotrophic ultramicrobacteria.

Withdrawn: Hair Analysis for Drug‐Facilitated Crime: The Critical Role of Hair Growth Rate

2019 ◽  
Vol 64 (5) ◽  
pp. 1574-1575 ◽  
Author(s):  
Gideon Koren ◽  
Elad Bellaish ◽  
Karen Maman
Keyword(s):  
Growth Rate ◽  
Hair Growth ◽  
Hair Analysis ◽  
Critical Role
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