Studies in fleece-rot of sheep.

RH Hayman

doi:10.1071/ar9530430

Studies in fleece-rot of sheep.

Australian Journal of Agricultural Research ◽

10.1071/ar9530430 ◽

1953 ◽

Vol 4 (4) ◽

pp. 430 ◽

Cited By ~ 30

Author(s):

RH Hayman

Keyword(s):

Microscopic Examination ◽

Similar Condition ◽

Unit Area ◽

Skin Surface ◽

Climatic Conditions ◽

Field Station ◽

Merino Sheep ◽

Naturally Occurring ◽

Sufficient Intensity ◽

Experimentally Induced

Occasions of unduly heavy and prolonged rainfall during the period April 1946 – July 1951 resulted in the occurrence of fleece-rot in sheep of the Field Station flock in each of the six years. Data obtained from periodic examinations of the flock have been related to the nature of climatic conditions associated with outbreaks of the disease. They show that when rain occurs in falls of sufficient intensity and frequency to wet sheep to the skin for a period of a week or more, fleece-rot may be expected to develop in some of them. The longer the period for which the sheep are kept wet, the greater the number in a flock which will be affected. Fleece-rot was experimentally induced in four out of five Merino sheep known to be susceptible to the condition, whereas five animals known to be resistant were unaffected by the same treatment. Microscopic examination of skin sections taken from naturally occurring cases revealed the presence of a dermatitis. A similar condition was observed in skin sections from the animals in which fleece-rot was experimentally induced. Young sheep were found to be more susceptible than old. There was no association between degree of wrinkling and susceptibility or between 'grip' and susceptibility. When subjectively-appraised attributes of the fleece were related to the occurrence of fleece-rot, confusing results were obtained. However, when measured fleece data, obtained from a group of Merino sheep which had been under observation for four consecutive years, were considered, it was found that those for clean-scoured yield, wax and suint ratio, and density of fibre population per unit area of skin surface, were related to resistance or susceptibility. Nevertheless, a number of animals were found which were susceptible or resistant to the disease despite the nature of their fleece attributes. Differences in susceptibility were found between families of Merino sheep. These are associated with between-family differences for the fleece attributes found to be important in fleece-rot reaction.

Download Full-text

Hebb-Type Dynamics is Sufficient to Account for the Inverse Magnification Rule in Cortical Somatotopy

Neural Computation ◽

10.1162/neco.1990.2.1.71 ◽

1990 ◽

Vol 2 (1) ◽

pp. 71-84 ◽

Cited By ~ 38

Author(s):

Kamil A. Grajski ◽

Michael M. Merzenich

Keyword(s):

Computer Simulation ◽

Receptive Field ◽

Cortical Neuron ◽

Inverse Relationship ◽

Unit Area ◽

Skin Surface ◽

Field Size ◽

Synaptic Modification ◽

Somatotopic Map ◽

Cortical Magnification

The inverse magnification rule in cortical somatotopy is the experimentally derived inverse relationship between cortical magnification (area of somatotopic map representing a unit area of skin surface) and receptive field size (area of restricted skin surface driving a cortical neuron). We show by computer simulation of a simple, multilayer model that Hebb-type synaptic modification subject to competitive constraints is sufficient to account for the inverse magnification rule.

Download Full-text

Response Of Maize Varieties To Sowing Dates In Inner Terai Region, Dang, Nepal

Malaysian Journal of Halal Research Journal ◽

10.2478/mjhr-2019-0011 ◽

2019 ◽

Vol 2 (2) ◽

pp. 27-31

Author(s):

Pukar Khanal ◽

Rupak Karn ◽

Pratibha Budhathoki Chhetri ◽

Samita Karki ◽

Shrawan Kumar Sah

Keyword(s):

Unit Area ◽

Block Design ◽

Climatic Conditions ◽

Spring Season ◽

Thousand Grain Weight ◽

Maize Hybrids ◽

Sowing Dates ◽

Maize Varieties ◽

Randomized Complete Block Design ◽

Hybrid Maize

AbstractSowing dates and varieties affect the productivity of maize. A field experiment was conducted to find out the response of maize hybrids to sowing dates on growth and productivity of maize in spring season at Lamahi, Dang in 2019. The experiment was laid out in two factor factorial Randomized Complete Block Design with four replications. The treatment consisted of combination of three different sowing dates (February 1, February12 and February 23) and two maize varieties (Arun-2 i.e. OPV and hybrid Bioseed-9220).The result revealed that earlier planting on February 1 produced the highest yield (8265 Kg ha-1) which was significantly superior than latter planting of February 12(6099 kg ha-1)and February 23 (5934 kg ha-1).The higher yield in earlier planting was due to significantly higher no of kernel per ear, non-significant but higher number of cob per unit area, thousand grain weight. Similarly, Bioseed 9220 produced higher yield (7798 kg ha-1) compared to Arun-2 (5,734 kg ha-1). The higher yield of hybrid Bioseed 9220 was because of higher number of cob per unit area harvested and more number of kernel per cob. Therefore, earlier planting with hybrid maize is recommended in spring season of Dang and locations with similar climatic conditions for higher productivity of maize.

Download Full-text

An Ultrastructural Autoradiographic Study of the Incorporation of [35S]Cystine in the Wool Fibre Cortex

Journal of Cell Science ◽

10.1242/jcs.13.3.811 ◽

1973 ◽

Vol 13 (3) ◽

pp. 811-819

Author(s):

R. E. CHAPMAN ◽

R. T. GEMMELL

Keyword(s):

Unit Area ◽

Autoradiographic Study ◽

Wool Fibre ◽

Cross Sectional ◽

Electron Microscope Autoradiography ◽

Merino Sheep ◽

Microscope Autoradiography ◽

Cystine Content ◽

Chemical Studies ◽

Filament Bundle

Previous autoradiographic and chemical studies gave incompatible results as regards the incorporation of cystine into and cystine content of the 2 cortical segments of the wool fibre. In this study the incorporation of [35S]cystine into the wool fibre cortex was therefore re-examined by electron-microscope autoradiography. Skin samples were taken from a Merino sheep 1 h and 5 h after intradermal injections of L-[35S]cystine. At both times there was very little incorporation of 35S in the follicle bulbs. By 5 h incorporation occurred distally from the suprabulbar region throughout the zone of macrofibril (filament bundle) formation. More 35S was incorporated per unit area in the paracortex than in the orthocortex, and at the level of maximal uptake near the middle of this zone there was about a 2-fold difference per unit area. However, when the relative cross-sectional areas of the cortical segments were also considered, the actual amount of 35S incorporated at this level was slightly greater in the orthocortex than in the paracortex. These differences in the incorporation of [35S]cystine by the cortical segments agreed with previous results from chemical studies on cortical fractions separated from wool.

Download Full-text

Phylogenomic Relationships of Diploids and the Origins of Allotetraploids in Dactylorhiza (Orchidaceae)

Systematic Biology ◽

10.1093/sysbio/syz035 ◽

2019 ◽

Vol 69 (1) ◽

pp. 91-109 ◽

Cited By ~ 16

Author(s):

Marie K Brandrud ◽

Juliane Baar ◽

Maria T Lorenzo ◽

Alexander Athanasiadis ◽

Richard M Bateman ◽

...

Keyword(s):

Phylogenetic Relationships ◽

Diploid Species ◽

Climatic Conditions ◽

Likelihood Methods ◽

Allopolyploid Speciation ◽

Naturally Occurring ◽

Maximum Likelihood Methods ◽

History Of ◽

Challenging Situation ◽

Age Estimates

Abstract Disentangling phylogenetic relationships proves challenging for groups that have evolved recently, especially if there is ongoing reticulation. Although they are in most cases immediately isolated from diploid relatives, sets of sibling allopolyploids often hybridize with each other, thereby increasing the complexity of an already challenging situation. Dactylorhiza (Orchidaceae: Orchidinae) is a genus much affected by allopolyploid speciation and reticulate phylogenetic relationships. Here, we use genetic variation at tens of thousands of genomic positions to unravel the convoluted evolutionary history of Dactylorhiza. We first investigate circumscription and relationships of diploid species in the genus using coalescent and maximum likelihood methods, and then group 16 allotetraploids by maximum affiliation to their putative parental diploids, implementing a method based on genotype likelihoods. The direction of hybrid crosses is inferred for each allotetraploid using information from maternally inherited plastid RADseq loci. Starting from age estimates of parental taxa, the relative ages of these allotetraploid entities are inferred by quantifying their genetic similarity to the diploids and numbers of private alleles compared with sibling allotetraploids. Whereas northwestern Europe is dominated by young allotetraploids of postglacial origins, comparatively older allotetraploids are distributed further south, where climatic conditions remained relatively stable during the Pleistocene glaciations. Our bioinformatics approach should prove effective for the study of other naturally occurring, nonmodel, polyploid plant complexes.

Download Full-text

Breed and seasonal differences in quantities of lipids on skin surface and hair in cattle

The Journal of Agricultural Science ◽

10.1017/s0021859600026034 ◽

1970 ◽

Vol 75 (1) ◽

pp. 41-46 ◽

Cited By ~ 14

Author(s):

Y. S. Pan

Keyword(s):

Unit Area ◽

Skin Surface ◽

Seasonal Differences

SUMMARYDifferences between Sahiwals and Jerseys and between summer and winter in the quantities of lipids on the skin surface and on hair were studied.Sahiwals had significantly greater quantities of lipids on both the skin surface and hair in summer and in winter. In both breeds, there were significantly greater amounts of lipids on the skin surface and on hair in winter. In both breeds a significantly greater quantity of lipids was present on hair than on skin in winter but not in summer.Jerseys had greater weight of hair/unit area of skin than Sahiwals in both summer and winter. There was no significant correlation between the amount of lipids on hair and the weight of hair.

Download Full-text

The value of production from a clipped measured area as an index of fleece weight.

Australian Journal of Agricultural Research ◽

10.1071/ar9550091 ◽

1955 ◽

Vol 6 (1) ◽

pp. 91 ◽

Cited By ~ 7

Author(s):

FHW Morley ◽

LW Lockart ◽

EC Davis

Keyword(s):

Body Weight ◽

Correlation Coefficient ◽

Unit Area ◽

Multiple Correlation Coefficient ◽

Multiple Correlation ◽

Merino Sheep ◽

Wool Production ◽

Fleece Weight ◽

Selection Of

The correlation between greasy wool production per unit area, obtained by clipping and measuring an area of about 100 cm² on the midside, and greasy fleece weight at shearing was about 0.58. Wool production from such an area over periods of 7½ or 3½ months was almost as useful as production for 11 months for predicting greasy fleece weight. The multiple correlation coefficient between greasy fleece weight as the dependant variable and production per unit area and 11-months' body weight was 0.79 in 66 rams and 0.71 in 82 ewes. The inclusion of fold score did not improve prediction appreciably. The equation W = P/110 + B1 /12 may be used to predict greasy fleece weight (lb), W, where P is production over 11 months of greasy wool (mg/cm²) and B1 is 11-months' body weight (Ib). A table of this function is included so that values may be read directly. The technique may be a useful aid to selection of Merino sheep if recording of actual fleece weights is difficult or impossible. Nevertheless it should not be regarded as more than a moderately accurate substitute for actual fleece-weighing.

Download Full-text

The effect of some fleece characters on the skin wax layer and fleece rot development in Merino sheep following wetting

Australian Journal of Agricultural Research ◽

10.1071/ar9840413 ◽

1984 ◽

Vol 35 (3) ◽

pp. 413 ◽

Cited By ~ 1

Author(s):

PJ James ◽

GH Warren ◽

A Neville

Keyword(s):

Moisture Content ◽

Cholesterol Content ◽

Skin Surface ◽

Proximal Portion ◽

Average Thickness ◽

Initial Thickness ◽

Merino Sheep ◽

Early Stages ◽

Wax Content ◽

Tip Formation

This paper describes changes occurring on the skin surface following wetting and during the development of fleece rot and examines the effect of some fleece characters on these changes. One day of wetting reduced the average thickness of the skin wax layer from 7.82 to 4.90 �m, but there was little change In the proportion of the skin surface covered by wax. When hyperaemia of the skin was first noted the proportion of the skin surface covered by wax had decreased from 97.8 to 47.5% and the average thickness of skin wax had decreased to 3.64 �m. Cholesterol content of the skin wax increased steadily from the first day of wetting as fleece rot developed, whereas lanosterol content increased only in the early stages of fleece rot. Suint content of the fleece, measured before wetting commenced, was positively correlated with fleece rot score at all times during wetting. Suint also showed significant correlations with moisture content of the proximal portion of the staple, percentage of the skin surface covered by wax and cholesterol and lanosterol content of the wax. No relationship was observed between fleece rot score and fleece wax content, wettability, staple formation, tip formation, crimp definition or initial thickness of the skin wax layer.

Download Full-text

Effects of Experimentally Induced Fleece-rot on the Structure of the Skin of Merino Sheep

Australian Journal of Biological Sciences ◽

10.1071/bi9820545 ◽

1982 ◽

Vol 35 (5) ◽

pp. 545 ◽

Cited By ~ 5

Author(s):

DE Hollis ◽

RE Chapman ◽

JA Hemsley

Keyword(s):

Histological Examination ◽

Merino Sheep ◽

Trunk Region ◽

Simulated Rain ◽

Skin Samples ◽

Experimentally Induced

Four medium- and six strong-wool Merino sheep were exposed to continuous simulated rain (4'5 mm/h) for periods ranging from 3 to 9 days. In response, the sheep developed characteristics typical of fleece-rot lesions such as exudative encrustation' and bacterial discoloration of the fleece. Skin samples were taken periodically for histological examination from the trunk region of the sheep prior to, during, and after wetting.

Download Full-text