scholarly journals Thermoregulatory response of Yankasa sheep with distinct thick-coarse and shortslick hair types during hot-dry season in tropical Savannah

2021 ◽  
Vol 48 (2) ◽  
pp. 167-182
Author(s):  
B. Habibu ◽  
I. Abdullahi ◽  
M. Hussaini ◽  
H. U. Buhari

The skin has the closest contact with the environment and, thus, the role of coat in the adaptation to the changing environmental conditions cannot be over emphasised. The study was aimed at comparing the thermoregulatory response of Yankasa rams with distinct thick coarse and short-slick hair types at the peak of the hot-dry season in tropical Guinea Savannah. A total of 10 Yankasa rams with thick-coarse (n=5) and short-slick (n=5) hair types, balanced for age and body condition score were used. The meteorological and thermoregulatory parameters were measured four times at 2 days interval at 9:00, 13:00 and 17:00 h. In the afternoon, the temperature humidity index and ambient temperature were higher than the thermoneutral zone for sheep. Yankasa sheep with thick-coarse hair had higher (P < 0.05) hair length than those with short-slick hair type. Respiratory rate at all hours, body surface temperature in the morning hours, eye and inter-digital surface temperature in the afternoon hours were lower in thick-coarse hair than short-slick hair sheep. Significant rise (P < 0.05) in respiratory rate, skin and rectal temperatures from morning to afternoon hours were observed in both hair types. Subsequently, in the evening hours, the rectal temperature in the thick-coarse hair sheep returned to values comparable to those of the morning hours; while the values in short-slick hair sheep remained higher (P <0.05) than that of the morning hours. It was concluded that Yankasa sheep with thick-coarse hair type had lower thermoregulatory demand to maintain homeostasis in the afternoon hours, and cooled faster in the evening hours relative to their short-slick hair type counterpart during the hot-dry season in the tropical Savannah.     La peau a le contact le plus facile avec l'environnement et, par conséquent, le rôle du pelage dans l'adaptation aux conditions environnementales changeantes ne peut pas être trop souligné. L'étude visait à comparer la réponse thermorégulatrice des béliers yankasa avec des types distincts de cheveux épais-grossiers et courts au plus fort de la saison chaude et sèche dans la savane tropicale de Guinée. Un total de 10 béliers Yankasa avec des types de cheveux épais-grossiers (n=5) et short-slick (n=5), équilibrés pour l'âge et le score d'état corporel ont été utilisés. Les paramètres météorologiques et thermorégulateurs ont été mesurés quatre fois à intervalles de 2 jours à 9 h, 13 h et 17 h. Dans l'après-midi, l'indice d'humidité de la température et la température ambiante étaient plus élevés que la zone thermonéutrale pour les moutons. Les moutons Yankasa aux cheveux épais et grossiers avaient une longueur de cheveux plus élevée (P < 0.05) que ceux de type cheveux courts. La fréquence respiratoire à toute heure, la température de surface du corps le matin, la température des yeux et de la surface inter-numérique dans les heures de l'après-midi étaient plus faibles dans les cheveux épais-grossiers que les moutons cheveux courts lisses. Des hausses significatives (P < 0.05) des températures respiratoires, cutanées et rectales du matin à l'après-midi ont été observées dans les deux types de cheveux. Par la suite, le soir, la température rectale chez les moutons aux cheveux épais-grossiers est revenue à des valeurs comparables à celles des heures du matin; tandis que les valeurs chez les moutons à poils courts sont restées plus élevées (P < 0.05) que celles des heures du matin. Il a été conclu que les moutons Yankasa de type cheveux épais-grossiers avaient une demande thermorégulatrice plus faible pour maintenir l'homéostasie dans les heures de l'après-midi, et refroidi plus rapidement dans les heures du soir par rapport à leur homologue de type cheveux courts lisses pendant la saison chaude-sèche dans la savane tropicale

2021 ◽  
Vol 4 (4) ◽  
pp. p16
Author(s):  
Bernard Tarza Tyubee ◽  
Raymond NlemadimChima Anyadike

The study analysed variation in surface temperature (ST) in Makurdi Urban Area (MUA), Northcentral Nigeria. A total of 12 Landsat TM/ETM+ images were acquired in January, April and June of 1991, 1996, 2001 and 2006. The ST was estimated from the 12 Landsat TM/ETM+ images, grouped into seven classes, and the area of each ST class was determined using remote sensing and Geographic Information System (GIS). The ST magnitudes vary spatially from 27.5oC (water bodies) to 50.7oC (built-up land), representing an intensity of 23.2oC. The mean seasonal ST varies from 32.4oC-34.5oC (cool-dry season), 35.5oC-38.8oC (hot-dry season) and 30.8oC-31.4oC (hot-wet season). The mean annual ST has increased from 32.9oC (1991) to 35.9oC (2006) with ST intensity of 3.0oC. The ST classes of 27oC-29oC and 33oC-37oC recorded the highest loss and gain in area of -126.5km2 and 94.5km2 whereas ST classes of 29oC-33oC and 41oC-45oC recorded the least and highest per centage change in area of 22% and 768%. The result showed decreasing and increasing trends in the areas of cooler and warmer surfaces, which are attributed to increase in anthropogen surface materials, with higher heat storage capacities, due to urbanisation.


Fire Ecology ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Willem A. Nieman ◽  
Brian W. van Wilgen ◽  
Alison J. Leslie

Abstract Background Fire is an important process that shapes the structure and functioning of African savanna ecosystems, and managers of savanna protected areas use fire to achieve ecosystem goals. Developing appropriate fire management policies should be based on an understanding of the determinants, features, and effects of prevailing fire regimes, but this information is rarely available. In this study, we report on the use of remote sensing to develop a spatially explicit dataset on past fire regimes in Majete Wildlife Reserve, Malawi, between 2001 and 2019. Moderate Resolution Imaging Spectroradiometer (MODIS) images were used to evaluate the recent fire regime for two distinct vegetation types in Majete Wildlife Reserve, namely savanna and miombo. Additionally, a comparison was made between MODIS and Visible Infrared Imager Radiometer Suite (VIIRS) images by separately evaluating selected aspects of the fire regime between 2012 and 2019. Results Mean fire return intervals were four and six years for miombo and savanna vegetation, respectively, but the distribution of fire return intervals was skewed, with a large proportion of the area burning annually or biennially, and a smaller proportion experiencing much longer fire return intervals. Variation in inter-annual rainfall also resulted in longer fire return intervals during cycles of below-average rainfall. Fires were concentrated in the hot-dry season despite a management intent to restrict burning to the cool-dry season. Mean fire intensities were generally low, but many individual fires had intensities of 14 to 18 times higher than the mean, especially in the hot-dry season. The VIIRS sensors detected many fires that were overlooked by the MODIS sensors, as images were collected at a finer scale. Conclusions Remote sensing has provided a useful basis for reconstructing the recent fire regime of Majete Wildlife Reserve, and has highlighted a current mismatch between intended fire management goals and actual trends. Managers should re-evaluate fire policies based on our findings, setting clearly defined targets for the different vegetation types and introducing flexibility to accommodate natural variation in rainfall cycles. Local evidence of the links between fires and ecological outcomes will require further research to improve fire planning.


2014 ◽  
Vol 43 (1) ◽  
pp. 52-60 ◽  
Author(s):  
Victor Olusegun Sinkalu ◽  
Joseph Olusegun Ayo ◽  
Ariyo Adelaja Abimbola ◽  
Josiah Egbamushe Ibrahim

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 455-455
Author(s):  
Raquel V Lourencon ◽  
Lionel J Dawson ◽  
Ryszard Puchala ◽  
Luana P Ribeiro ◽  
Terry A Gipson ◽  
...  

Abstract Twenty-five Dorper (D), 27 Katahdin (K), and 33 St. Croix (S) ewes were used to characterize changes in BW, body condition score (BCS), body mass index (BMI), and body composition with different nutritional planes before breeding. Supplement treatments were soybean meal fed at 0.16% BW and 25% soybean meal and 75% ground corn at 0.8% BW (DM; L and H, respectively). There were two animal groups and pens per breed and supplement treatment. Shrunk BW (20 h without feed and water), BCS (1–5), linear measures including wither height and length from the point of the shoulder to pin bone, and body composition via urea space were determined after 0, 4, and 8 wk. Initial values were 62.10, 59.99, 61.57, 62.25, 50.23, and 52.98 kg shrunk BW (SEM=3.601); 35.82, 34.81, 35.57, 36.41, 33.77, and 34.09% fat (SEM=1.043); 17.06, 16.72, 16.98, 17.27, 16.38, and 16.49 MJ/kg energy (SEM=0.357); 3.29, 3.41, 3.29, 3.29, 2.99, and 3.18 BCS (SEM=0.139); and 13.72, 14.22, 12.69, 12.81, 11.53, and 11.50 g/cm2 BMI (BW/(height×length); SEM=0.463) for D-L, D-H, K-L, K-H, S-L, and S-H, respectively. Change from wk 0 to 8 was -0.80, 2.90, -2.74, 3.33, -2.02, and 3.36 kg shrunk BW (SEM=0.842); -0.14, 2.03, -1.45, 1.70, -0.85, and 2.10 kg fat (SEM=0.862); -8.4, 83.7, -62.5, 73.8, -38.4, and 88.1 MJ energy (SEM=33.30); -0.02, 0.20, 0.04, 0.29, -0.08, and 0.17 BCS (SEM=0.070); and -0.265, 0.297, -0.185, 0.491, -0.571, and 0.587 g/cm2 BMI (SEM=0.488) for D-L, D-H, K-L, K-H, S-L, and S-H, respectively. Correlation coefficients between change in BCS and mass of water, fat, and energy were 0.35 and 0.44 (P ≤ 0.004), and those for BMI were 0.54 and 0.56, respectively (P &lt; 0.001). In conclusion, a BMI can be more highly related to and predictive of change in body composition of hair sheep resulting from different nutritional planes compared with BCS.


2019 ◽  
Vol 59 (1) ◽  
pp. 148
Author(s):  
Geoffry Fordyce ◽  
Kerri Chandra

Growth of 1368 Brahman cross heifers from 6 year cohorts was monitored over the 2 years post-weaning in Australia’s northern forest, a low-animal-growth dry tropical environment. Heifers weighing 47–266 kg at weaning were managed in groups weighing &lt;100 kg, 100–149 kg, 150–199 kg, and &gt;199 kg during the post-weaning dry season. Weaner heifers were allocated to receive 300 g/day of a protein meal during the dry season or to basic nutritional management to sustain health. Heifers in three cohorts were allocated to first mating at 1 or 2 years of age, in four cohorts to vaccination against androstenedione, and in a small proportion of two cohorts to ovariectomy post-weaning. Growth was highly variable between seasons and years; average cohort liveweight by the start of 2-year-old mating was 256–319 kg. Heifer groups not receiving protein supplementation gained –16 to 21 kg (2 kg average) during 6-month dry seasons, and 49–131 kg (101 kg average) during wet seasons to reach an average of two-thirds of mature liveweight (445 kg) and 95% of mature hip height (1350 mm) by the start of mating at 2 years. Average body condition score (1–5) fluctuated by 1–2 units between seasons. Hip height gain continued, irrespective of season, commencing at ~0.60 mm/day at 6 months of age, and decelerating by ~0.00075 mm/day through to 2.5 years of age. Standard errors of predicted means across analyses were ~0.015 for average daily weight gains, 0.4 mm for average monthly height gain and 0.06 score units for average seasonal body condition score change. Post-weaning dry-season supplementation increased gains in liveweight, height and body condition score by an average of 0.1 kg/day, 0.1 mm/day and 0.5 units, respectively, during the supplementation period. Periods of poor nutrition or high nutritional demand secondary to reproduction suppressed daily gains in liveweight and hip height, at which times body condition score was also reduced. Subsequent to this, partial to full compensation occurred for all measures. Ovariectomy had negative effects on growth. Androstenedione vaccination had no effect on growth. The main conclusion is that heifer growth in Australia’s dry tropical northern forest region is highly variable between seasons and years, thus limiting significant proportions of some cohorts from reaching target weights for mating at 2 years of age, even after compensatory growth.


2020 ◽  
Vol 12 (24) ◽  
pp. 4067
Author(s):  
Thanhtung Dang ◽  
Peng Yue ◽  
Felix Bachofer ◽  
Michael Wang ◽  
Mingda Zhang

Global warming-induced climate change evolved to be one of the most important research topics in Earth System Sciences, where remote sensing-based methods have shown great potential for detecting spatial temperature changes. This study utilized a time series of Landsat images to investigate the Land Surface Temperature (LST) of dry seasons between 1989 and 2019 in the Bac Binh district, Binh Thuan province, Vietnam. Our study aims to monitor LST change, and its relationship to land-cover change during the last 30 years. The results for the study area show that the share of Green Vegetation coverage has decreased rapidly for the dry season in recent years. The area covered by vegetation shrank between 1989 and 2019 by 29.44%. Our findings show that the LST increase and decrease trend is clearly related to the change of the main land-cover classes, namely Bare Land and Green Vegetation. For the same period, we find an average increase of absolute mean LST of 0.03 °C per year for over thirty years across all land-cover classes. For the dry season in 2005, the LST was extraordinarily high and the area with a LST exceeding 40 °C covered 64.10% of the total area. We expect that methodological approach and the findings can be applied to study change in LST, land-cover, and can contribute to climate change monitoring and forecasting of impacts in comparable regions.


1959 ◽  
Vol 37 (1) ◽  
pp. 1247-1253 ◽  
Author(s):  
O. Héroux

The effect of cold temperature on the skin was studied on white rats exposed to two different types of environmental conditions. Two groups of adult rats kept in individual cages were continuously exposed for 3 months to constant cold temperature (18° and 6 °C) in the laboratory (indoor rats) while other groups of the same colony kept in groups of 10 were exposed for the same length of time to the fluctuating environmental conditions prevailing outside (outdoor rats).Indoor rats acclimated to 18 °C and 6 °C showed the same increase in the number of opened capillaries in the ears over the number observed in controls acclimated to 30 °C. "Summer and winter" outdoor rats showed the same number of capillaries as the "18 °C or 6 °C" indoor rats. Signs of injury healing such as thicker epidermis and larger nuclei were found in the ears of all the "6 °C" rats but in none of the "winter" rats. While the skin temperature measured at + 6 °C was slightly higher (0.4 to 1.0 °C) in rats acclimated at 6 °C than in those at 30 °C, it was lower (1.3 to 2.9 °C) in "winter" than in "summer" rats. After 28 days of acclimation, the rate of oxygen uptake of the dorsal skin of the foot was lower in "6 °C" than in "30 °C" rats but after 84 days it was significantly higher in the cold-acclimated rats. Similarly, after 3 months, the respiratory rate of the dorsal skin of the foot was higher in "winter" rats than in "summer" rats.


2014 ◽  
Vol 59 (No. 10) ◽  
pp. 479-490 ◽  
Author(s):  
B. Habibu ◽  
MU Kawu ◽  
HJ Makun ◽  
T. Aluwong ◽  
LS Yaqub ◽  
...  

The current study was aimed at evaluating the effect of heat stress (during the hot-dry period) on some physiological variables, haematology and erythrocyte osmotic fragility (EOF) in bucks, pregnant (single and twin) and lactating Red Sokoto (RS) goats. Forty apparently healthy adult goats were used for the study and were allotted to four groups [bucks (n = 10), pregnant (n = 10) dry (n = 10), and lactating (n = 10) does]. The pregnant goats were further re-grouped according to number of foetuses (single foetus, n = 5 and twins, n = 5). The temperature-humidity index and physiological variables measured were significantly higher in the afternoon compared to morning hours. Pregnant does had higher respiratory and pulse rates than the dry does, but no significant change (P &gt; 0.05) in rectal temperature was observed between groups. On the basis of sex, bucks had lower (P &lt; 0.05) mean corpuscular volume (MCV) than other groups, in addition to having higher (P &lt; 0.01) mean corpuscular haemoglobin (MCH) and total leucocyte counts than dry does. Pregnant does exhibited significantly lower (P &lt; 0.05) packed cell volume, but significantly higher (P &lt; 0.05) MCH and mean corpuscular haemoglobin concentrations (MCHC) than lactating does. Does with a single foetus had significantly lower (P &lt; 0.05) MCV, but higher MCHC than does with twin pregnancies. Using EOF as a biomarker of oxidative stress, erythrocytes of bucks were significantly more resistant to hypotonic haemolysis than those of dry, pregnant and lactating does, with no significant difference in EOF between does of different groups. The erythrocytes of single and twin pregnancies showed similar haemolysis pattern. In conclusion, sex, lactation, and the number of foetuses carried by pregnant does significantly influences physiological and haematological variables in RS goats during the hot-dry season. Also, during heat stress, the changes in physiological variables seem to enhance favourable adaptation by preventing an increase in rectal temperature even in twin pregnancies. &nbsp;


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