Seasonal and regional variations in coat characteristics of dairy cattle

1961 ◽  
Vol 12 (3) ◽  
pp. 528 ◽  
Author(s):  
A Berman ◽  
R Volcani
Keyword(s):  
Annual Cycle ◽  
Fibre Diameter ◽  
Day Length ◽  
Mean Annual Temperature ◽  
Maximum Weight ◽  
Jordan Valley ◽  
Natural Conditions ◽  
Climatic Regions ◽  
Hair Fibre ◽  
Hair Diameter

The annual cycle in coat growth and shedding rates was investigated in Holstein and Syrian x Holstein cattle (3.1-6.2% relationship to the Syrian) under natural conditions in three different climatic regions of Israel. Hair quantity, coat thickness, and hair diameter were tested monthly on an area of 100 cm2 on the thigh. 541 samples were taken during 1 year. Cows were tested in two herds in the Jordan Valley (mean annual temperature 23�C), one herd in the Coasral Plain (mean annual temperature 20.4�C), and one in the Jerusalem area (mean annual temperature 17.5�C). Hair quantity and coat thickness in the Jordan Valley were very- significantly smaller than in the other two regions. A clear cycle was observed in these three factors. Weight of hair reached the peak In January, then decreased to 50% of the maximum weight during April-Nay and increased again during May-June, reaching 75% of the maximum weight. From October hair growth continued, to the peak in January. Variations in coat thickness differed from those in weight of hair during summer, when coat thickness stayed lox and stable until autumn. Hair fibre diameter was lowest between December and March, then increased sharply until June. Hair quantity and coat thickness decreased more and faster in the Jordan Valley. These results show that day length is not the only factor influencing the annual cycle of hair quantity and coat thickness but that, apparently, the air temperature? are of influence too. In this experiment hair diameter was influenced only by variations in day length.

CYCLICAL CHANGES IN THE TESTICULAR ACTIVITY OF THE LAKE CHUB, COUESIUS PLUMBEUS (AGASSIZ)

1966 ◽  
Vol 44 (2) ◽  
pp. 149-159 ◽  
Author(s):  
Syed Nazar Ahsan
Keyword(s):  
Environmental Factors ◽  
Water Temperature ◽  
Quantitative Evaluation ◽  
Annual Cycle ◽  
Day Length ◽  
Temperate Latitude ◽  
Histochemical Methods ◽  
Couesius Plumbeus

The cyclical changes in the activity of the testes of a teleost, the lake chub, from a north temperate latitude have been studied by histological and histochemical methods with a quantitative evaluation of the different spermatogenetic stages. The annual testicular cycle is divided into live stages and cyclical changes in the spermatogenetic activity have been related to the changing environmental factors, namely day length and water temperature. The annual cycle consists of a prolonged mitotic phase during the fall and winter, and a shorter meiotic phase during the spring. Lobule boundary cells have been examined and changes in their activity have been recorded. Continued spermatogenetic activity during spawning enables repeated spermiation, which is advantageous since the males are comparatively fewer than the females.

Permafrost thermal amelioration tests near Schefferville, Quebec

1976 ◽  
Vol 13 (12) ◽  
pp. 1694-1705 ◽  
Author(s):  
Frank H. Nicholson
Keyword(s):  
Snow Depth ◽  
Heat Losses ◽  
Mean Annual Temperature ◽  
Net Radiation ◽  
Natural Conditions ◽  
Plot Size ◽  
Summer Heat ◽  
Snow Fences ◽  
Test Result ◽  
Lateral Heat

Permafrost thermal amelioration techniques have been tested for 4 years near Schefferville (mean annual temperature −6 °C). The most important amelioration measure tested was the use of snow fences to increase snow depth and hence reduce winter heat losses, which affect the permafrost much more than changing the summer heat input conditions. However, when different summer treatments were tested, stripping the vegetation, darkening the ground and using thin transparent covers proved beneficial. Monitoring included deep ground temperature measurements (to 25 m), radiation instruments, lysimeters, and measurement of ground thermal properties. At 5 m depth, between 20 and 40 × 106 Jm−2 are gained and lost each year under natural conditions, whereas the amelioration gave a continuous gain of 20 × 106 Jm−2 per annum (nearly 2% of net radiation), increasing mean temperature by 2.5 °over 4 years. At the 10 m depth corresponding gains were 10 × 106 Jm−2 and 1.5°. The rocks (iron-rich) have high thermal conductivities, and slower amelioration results are likely in other areas. Limited plot size (7500 m2) has resulted in significant lateral heat loss. The overall test result is that the active layer has been greatly deepened but no thaw has yet been held through a full winter. The method would be useful in several mining applications, including the prevention of new permafrost.

Environmental cues of estrus in the North American red squirrel (Tamiasciurus hudsonicus Bangs)

1993 ◽  
Vol 71 (7) ◽  
pp. 1326-1333 ◽  
Author(s):  
C. Dustin Becker
Keyword(s):  
Annual Cycle ◽  
Energy Gain ◽  
Day Length ◽  
Tamiasciurus Hudsonicus ◽  
Positive Energy ◽  
Net Energy ◽  
Circannual Rhythm ◽  
Red Squirrels ◽  
Short Day ◽  
Net Energy Gain

During three breeding seasons, variation in the timing of estrus was monitored in wild red squirrels (Tamiasciurus hudsonicus) in a jack pine forest in central Alberta. The proximate environmental factors that affect the timing of the onset of the breeding season in female squirrels, and variation in dates of estrus, were studied in parallel laboratory and field manipulations. Wild squirrels given ad libitum sunflower seed experienced a positive energy balance (weight gains) earlier in the season than did females on a normal diet. Seed addition advanced dates of estrus by an average of 3 weeks. Three potential cuing mechanisms for the seasonal onset of estrus were proposed and tested: onset of estrus is cued by (i) a simple response to net energy gain, (ii) an interaction between an endogenous circannual rhythm and net energy gain, or (iii) an interaction between annual changes in photoperiod and net energy gain in the absence of a circannual rhythm. Our results refute the first and third mechanisms, and support the idea that red squirrels have a circannual reproductive cycle entrained by photoperiod. Net energy gain interacts with this annual cycle to fine tune the time of ovulation. In laboratory experiments, female squirrels exposed to increasing day length experienced estrus within the normal season. Squirrels kept in constant short-day conditions (< 12 h), had delayed estrus cycles. Short-day conditions did not prevent the annual cycle of reproduction, indicating that an endogenous rhythm exists and is entrained by increasing day length. Comparisons with hibernating squirrels are discussed.

The ratio of moisture and chemicals in the processes of infiltration and evaporation of groundwater in soddy-podzolic loamy soil

2020 ◽  
pp. 22-26
Author(s):  
Nikolay Muromcev ◽  
Dmitry Kucher ◽  
Elena Piven ◽  
Nikolay Semenov ◽  
Kirill Anisimov
Keyword(s):  
Annual Cycle ◽  
Podzolic Soil ◽  
Capillary Rise ◽  
Soddy Podzolic Soil ◽  
Natural Conditions ◽  
Loamy Soil ◽  
The Real ◽  
Gleyed Soil

The specificities of leaching (outflow) of chemicals from soddy-podzolic loamy deeply gleyed soil by infiltration and its return from groundwater during their evaporation are considered in the paper. In the annual cycle calcium is the element which is mostly washed out with amount of 89…106 kg/ha. It was shown that potassium (15…14), manganese (13,6…9,3), zinc (13,6…7,7), calcium (7,5…5,2) and magnesium (7,1…4,7) in percentage of the outflow return in the soil with the capillary rise of groundwater. It is shown that the ratio of infiltration (I) and evaporation of groundwater (K) in soddy-podzolic soil is within the range of 0,3…0,6 for medium arid, 2,6…2,9 for average long-term and 2,6…2,9 for humid conditions of atmospheric moistening. Thus, the lowest values of ratios for medium arid, and the highest ones – for medium humid conditions, which reflects the real specificities of the infiltration and evaporation of groundwater in natural conditions.

Interaction of photoperiod and temperature in the regulation of prediapause development in the spotted tentiform leafminer (Lepidoptera: Gracillariidae)

2001 ◽  
Vol 133 (2) ◽  
pp. 251-253
Author(s):  
R.M. Trimble
Keyword(s):  
Larval Development ◽  
Strong Interaction ◽  
Development Time ◽  
Day Length ◽  
Environment Canada ◽  
Natural Conditions ◽  
Increased Temperature ◽  
Temperature Environment ◽  
Pupal Diapause ◽  
Phyllonorycter Blancardella

The spotted tentiform leafminer, Phyllonorycter blancardella (F.), overwinters in a photoperiodically induced state of pupal diapause. The critical day length (50% of leafminers enter diapause) for P. blancardella from latitudes of about 42–44°N in southwestern Ontario was 14.25 h at an average August temperature (Environment Canada 1993) of 20°C (Trimble 1994). The development time of actively growing larvae decreased with increased temperature, whereas the development time of diapause-destined larvae was not affected by temperature at the critical day length, suggesting a strong interaction between photoperiod and temperature in the regulation of prediapause development (Trimble 1994). This paper describes the interaction of photoperiod and temperature in the regulation of the rate of egg and larval development of diapausedestined leafminers in the laboratory and in semi-natural conditions.

scholarly journals Altxunbidëa. Estudio etnofotográfico del ciclo anual trashumante roncalés

2020 ◽  
pp. 143-194
Author(s):  
Carlos Orduna Portús
Keyword(s):  
Annual Cycle ◽  
Character Traits ◽  
Mountain Range ◽  
Livestock Farming ◽  
Climatic Regions ◽  
Expository Discourse ◽  
Winter Grazing ◽  
Stock Model

RESUMEN Este estudio contribuye al análisis de un ciclo anual de ganadería extensiva desde una perspectiva transversal. En el trabajo se estudian los estadíos del pastoreo invernal en el semidesierto de las Bardenas, los usos y disfrutes de los puertos de la montaña y ambas cabañeras de desplazamiento entre las dos regiones geográficas y climáticas. En los resultados gráficos del análisis se observa no solo su componente de permanencia en las costumbres locales sino también las rápidas trasformaciones actuales palpables en su significación dentro del paisaje cultural de esta sociedad pirenaica. Se logra contextualizar un sistema pastoril que imperó hasta hace no mucho, no solo en Navarra sino en toda la señalada cordillera montañosa y en la depresión del Ebro. LABURPENA Azterlan honek abeltzaintza zabala urteko zikloa zeharkako ikuspegitik ikertzen laguntzen du. Lanean neguko artzaintzaren egonaldiak aztertzen ditugu Bardeako basamortuan edo mendiko larretan erabilerak eta gozamenak eta bi eskualde geografiko eta klimatikoen arteko abelbideak. Ikerlanaren emaitza grafikoetan, tokiko ohituretan iraunkortasunaren egiturak eta egungo eraldaketa azkarrak ere ikusten dira. Pirinioetako gizarte honetako kultura paisaian, aldaketa hauek haien garrantzia ikusgai daude. Ikuspuntu integraletik, artzain-errealitatearen bilakaera maila grafikoan eta antropologikoki testuinguruan ahala da. Horrela, Nafarroan eta beste toki batzuetan, gaur egungo abeltzaintza ereduaren bilakaeraren ebaluazioarekin amaitu da. ABSTRACT The work analyzes the annual cycle of extensive livestock farming from a transversal perspective. This paper concerns the studies of the stages of winter grazing in the semi-desert of the Bardenas, the uses and enjoyments of the mountain pastures and the cattle routes between the two geographical and climatic regions. Paper aims to contextualize by graphs the analysis of the customs and anthropological level the evolution of this pastoralist reality from an integral perspective and clear expository discourse. Thus, the study concludes with an assessment of the evolution, loss or conservation of character traits of this stock model in the mountain range and the Ebro Lowland.

The role of water in the behaviour of an estuarine mud-flat diatom

1966 ◽  
Vol 46 (3) ◽  
pp. 617-626 ◽  
Author(s):  
J. T. Hopkins
Keyword(s):  
Diurnal Rhythm ◽  
Day Length ◽  
Diatom Community ◽  
Natural Conditions ◽  
Mud Flat ◽  
Tidal Rhythm

The tidal rhythm of migration of the mud-fiat diatom community is a curtailed diurnal rhythm. Evidence is given of the similarity of these two oscillations in the laboratory and in the natural conditions of the estuary. However, the interference of the diurnal rhythm by water or stirring results only in one repeated rhythm on the following day; thereafter the migrations revert to a day-length-induced synchronization.

Initiation and development of western red cedar cones in response to gibberellin induction and under natural conditions

1971 ◽  
Vol 49 (7) ◽  
pp. 1165-1175 ◽  
Author(s):  
J. N. Owens ◽  
R. P. Pharis
Keyword(s):  
Cold Treatment ◽  
Day Length ◽  
Thuja Plicata ◽  
Natural Conditions ◽  
Red Cedar ◽  
Cone Type ◽  
Cone Development ◽  
Cone Apex ◽  
Lateral Branches ◽  
Pollen Cone

Both seed and pollen cones in Thuja plicata Donn. are found at the tips of small lateral branches and form as a result of the transition of previously vegetative apices. The vegetative apex shows a cytohistological zonation similar to that found in other Cupressaceae and vegetative buds are not enclosed in scales. The first sign of pollen cone initiation occurred 13 days after the initial GA3 treatment under long days. Transition of the apex was marked by a slight increase in rate of cell division in all zones resulting in the formation of a mantle of small uniform cells several cells thick covering the surface of the apex. The apex increased in height and the long internode between the last-formed pair of leaf primordia and first pair of microsporophylls formed a short stalk at the base of the cone. The transition of a vegetative apex to a seed cone apex occurred 27 days after initial GA3 treatment and was similar to that for pollen cones. Bract primordia are initiated closer to the summit of the apex and are larger in initial stages than microsporophyll primordia, and longer internodes remain between successive pairs of bracts. Ovule initiation occurs when bracts have just begun upward growth. All microsporophylls, bracts, and ovules are formed during the few weeks after cone initiation and before cones become dormant. No anatomical changes occurred in either cone type during subsequent short-day cold treatment. A return to long-day warm conditions promoted normal cone development. Under natural conditions in the Victoria area, pollen cones are initiated early in June under long days and increasing day length while seed cones are initiated early in July under similar long days but decreasing day length. Development of both pollen and seed cones occurs during long days and decreasing day length. The possible relationship between sexuality of cones, gibberellin, auxin, and day length is discussed.

scholarly journals Influence of seasonal changes in daily activity and annual life cycle of Geotrigona mombuca (Hymenoptera, Apidae) in a Cerrado habitat, São Paulo, Brazil

2013 ◽  
Vol 103 (4) ◽  
pp. 367-373
Author(s):  
André L. Gobatto ◽  
Fátima R. N. Knoll
Keyword(s):  
Annual Cycle ◽  
Seasonal Changes ◽  
Meteorological Factors ◽  
Flight Activity ◽  
Late Winter ◽  
Foraging Activity ◽  
Natural Conditions ◽  
Annual Life Cycle ◽  
Survival And Reproduction ◽  
Microclimate Conditions

The foraging activity of Geotrigona mombuca Smith, 1863 was studied under natural conditions aiming to verify the influence of seasonal changes on daily flight activity and annual cycle of the colony. Daily flight activity was monitored for a year based on the observation and counting of foragers leaving and entering the hive, as well as the kind of material transported and meteorological factors such as day time, temperature and relative humidity. The influence of seasonal changes was evidenced by alterations on daily rhythm of flight activity and by differences on transportation of food resources, building material and garbage. These data indicate that forager behavior is related to daily microclimate conditions and it is synchronized with the requirements of colony annual cycle, which determines an intense pollen collection in the summer. Thus, the recomposition of the intranidal population in spring and summer can be ensured, which is characterized both for a higher intensity of flight activity and increase in garbage and resin transport, as well as the swarming process in the spring. In this way, an action targeting the preservation or management of the species in a natural environment should consider that survival and reproduction of the colony depends greatly on the amount of available pollen in late winter.

scholarly journals EPIDEMIOLOGY OF BLACKHEAD IN TURKEYS UNDER APPROXIMATELY NATURAL CONDITIONS

1920 ◽  
Vol 31 (5) ◽  
pp. 633-646 ◽  
Author(s):  
Theobald Smith ◽  
H. W. Graybill
Keyword(s):  
Food Supply ◽  
Field Experiments ◽  
The Other ◽  
Mean Annual Temperature ◽  
Infectious Agents ◽  
View Point ◽  
Natural Conditions ◽  
Chicken Pox ◽  
Sources Of Infection ◽  
Ground Material

The foregoing experiments in outdoor, unprotected enclosures demonstrates the difficulties surrounding the rearing of turkeys. These are discussed from another view-point and to avoid repetition only a few outlying facts should be considered here. The occasional presence of coccidia, the presence of Heterakis papillosa in the ceca, the occurrence of cases of aspergillosis and of chicken-pox in incubator-bred birds which did not come in contact with other domesticated birds, except in a few cases with incubator-bred chickens, show clearly that turkeys are picking up from the ground material deposited by other birds. The agent of blackhead must come from the same sources. The field experiments show a steadily increasing concentration of the infection from 1917 to 1919, even though the ground had been ploughed and seeded before use. As a result, the various groups of turkeys became infected to a greater degree. The growth in the intensity of the disease may be in part ascribed to an accumulation on the soil of infectious agents during any given season after they had been introduced, but it is hardly acceptable as an explanation from season to season, when the soul was either virgin, as regards poultry yards, or ploughed deep and seeded before use. A more rational hypothesis is the gradual attraction of birds in larger numbers and greater variety on account of the food supply in the turkey enclosures and the more intensive cultivation of the land surrounding the laboratory and animal buildings since the beginning of the experiments in 1917. The intensity of the outbreaks due to the confining of young turkeys with birds over a year old which had been infected during the preceding year, or on ground previously occupied by them, was in all instances much greater than in the spontaneous outbreaks. The cases amounted to nearly 100 per cent of the exposed. On the other hand, the number of cases in the control flocks varied and was very low in some groups. It could have been kept down if the sick birds had been promptly removed and not permitted to recover on the same ground. However, the object of the experiment was not to suppress the disease, but to see to what extent it would develop. It is self-evident that the results obtained apply strictly only to that part of the country where the experiments were made. We have at present no means of knowing whether the sources of infection would become more numerous and concentrated with a higher mean annual temperature, or the reverse. Only by using incubator turkeys exclusively for such tests and eliminating the older turkeys and domesticated birds as carriers, can the miscellaneous, at present not controllable sources of the agents of this disease in different localities and the chances of successful rearing be determined.

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