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The physiological basis of adaptation in goats to harsh environments
Abstract
Goat living in harsh environments represents a climax in the capacity of domestic ruminants to adjust to such areas. This
ability is multifactorial: low body mass, and low metabolic requirements of goats can be regarded as an important asset to
them for it minimise their maintenance and water requirements, in areas where water sources are widely distributed and food
sources are limited by their quantity and quality. An ability to reduce metabolism allows goats to survive even after prolonged
periods of severe limited food availability. A skillful grazing behaviour and ef®cient digestive system enable goats to attain
maximal food intake and maximal food utilisation in a given condition. There is a positive interaction between the better
recycling rate of urea and a better digestion of such food in desert goats. The rumen plays an important role in the evolved
adaptations by serving as a huge fermentation vat and water reservoir. The water stored in the rumen is utilised during
dehydration, and the rumen serves as a container, which accommodates the ingested water upon rehydration. The rumen, the
salivary glands and the kidney coordinately function in the regulation of water intake and water distribution following acute
dehydration and rapid rehydration. Goats in the tropics, when possible, eat a diet composed of tree-leaves and shrubs (browse),
which ensure a reliable and steady supply of food all year around, albeit, from a low to medium quality food. Some of the
physiological features of ruminants de®ned as intermediate feeders like large salivary gland, the large absorptive area of their
rumen epithelium, and the capacity to change rapidly the volume of the foregut in response to environmental changes are most
likely responsible for the goat's superior digestion capacity.
... Goats are good substitutes for traditional animal production in hot climatic conditions owing to their ability to adapt to different environments [1,2]. The animals possess both phenotypic adaptive features and the genetic mechanism that guarantee thermo tolerance in harsh environments around the world. ...
... Therefore, measuring respiration rate and determining animal heat stress severity according to panting rate (breaths/min) (low: 40-60, medium: 60-80, high: 80-120, and severe heat stress: >200) appears to be the most attainable method for evaluating the impact heat stress on animals under extreme environment [1,29]. ...
... Respiration rate may access 300 breaths/min with open-mouthed panting is a signal of severe heat stress [1]. Increased respiration rate following heat stress has been noticed in goats [30]. ...
This experiment was conducted at El-Obeid ARC Farm, Sudan, covered hot summer, rainy, winter and warm summer seasons for 310 days. Thirty-six non-pregnant Desert goats were used in this experiment. One group was randomly allocated to a shaded condition and the other to unshaded condition. Each group was randomly subdivided into two groups, one group receiving water every day and the other receiving water every other day. Does were mated by using two healthy Desert bucks. For both shaded and unshaded conditions, respiration rate (RR) and rectal temperature (RT) were significantly (P<0.001) higher in unshaded than shaded condition. Watering regime seemed to have no effect. Conception and kidding rates were lowest with the every other day watering regime under both shaded and unshaded conditions, while abortion rates was highest with the every other day watering regime under unshaded condition. Does mortality rate was highest in the shaded condition with the everyday watering regime and under unshaded condition with the every other day watering regime. Kids’ mortality rate was 100% under unshaded condition with the every other day watering regime. Kids’ birth weights were higher under shaded condition with every day watering regime or under unshaded condition with every other day watering regime. Key words: Desert goat, shade, watering regime, respiration rate, rectal temperature, seasons.
... Çiftlik hayvanlarında vücut boyutu ve şekli aşırı sıcak ortamlarda termoragülatör makanizmayı etkilemektedir. Kısmen daha küçük yapılı hayvanlar düşük yem ve su gereksinimlerine ihtiyaç duyarlar (Silanikove, 2000a;Cain vd., 2006;Brito vd., 2004). ...
... Çevre sıcaklığının artması hayvanlarda artan ayakta durma ve azalan yatış süreleri ile ilişkili olduğu, hayvanların güneş ışınlarının doğrudan ve dolaylı etkilerinden kaçınmak için kendilerini farklı yönlere çevirmek için ayakta daha fazla kaldığı bildirilmiştir. Ayrıca ayakta durma pozisyonunda hayvan vücudunun hava akımına veya rüzgara maruz kalma miktarını artırarak vücut ısı yükünün çevreye dağılmasını kolaylaştırdığı bildirilmiştir (Silanikove, 2000a;Provolo ve Riva, 2009;Endris ve Feki, 2021). ...
... Yapılan çalışmalarda stresin, hipofiz hormonlarının salgılanmasında değişikliklere neden olarak, metabolizmanın, bağışıklık sisteminin yanı sıra üremede olumsuzluklara yol açabileceğini (Moberg, 2000) ve sıcaklık stresine uyum ile ilişkili hormonların büyüme hormonu (GH), prolaktin (PRL), tiroid hormonları, mineralokortikoidler, glukokortikoidler, katekolaminler ve antidiüretik hormonu (ADH) olduğu bildirilmiştir (Sheba vd., 2012). Ayrıca sıcaklık stresi sırasında hipotalamo-pitutarya adrenal kortikal (HPA) aksının aktivasyonu, kortizol konsantrasyonunun artmasına neden olur (Silanikove, 2000a). Kumar vd. ...
... Small ruminants like sheep and goats have been primarily kept in various environments and grazing systems, requiring multiple adaptations, especially concerning temperature changes through thermoregulation [1]. From a biological perspective, thermoregulation can be defined as how animals maintain their core internal temperature through the physiological process of homeostasis [2]. ...
... Throughout the world, small ruminants are affected by heat stress regularly [6,7]. As a limiting factor, excessive heat stress can lead to impaired production, reproduction, compromised natural immunity, and increased susceptibility to diseases, in general, the well-being of the animals [1,4]. Heat stress affects ruminants s through various environmental factors like extreme temperatures, high solar radiation, relative humidity, wind, rainfall, and nutrition [8]. ...
... Heat stress affects ruminants s through various environmental factors like extreme temperatures, high solar radiation, relative humidity, wind, rainfall, and nutrition [8]. However, sheep and goats adapt to different environmental changes and often perform better during heat stress than other ruminants [1]. This review explains the process of thermoregulation in sheep and goats. ...
Thermoregulation is the capability of an animal to maintain its core internal temperature by homeostasis. Small ruminants like sheep and goats acclimate to different environmental changes and often perform better during heat stress than other ruminants. Adapting small ruminants to exceptional weather events occurs through behavioral, genetic, physiological, and morphological mechanisms. Small ruminants can mitigate the consequences of thermal stress using behavioral strategies such as consuming more water, looking for shade, consuming less feed, standing instead of lying down behavior, and other morphological mechanisms such as size, shape, coat color, coat depth, pigmentation, and fat storage. Small ruminants also respond to thermal changes through physiological mechanisms such as variations in respiration, heart rate, core temperature, sweating rate, metabolic rate, and endocrine functions. From the genetic point of view, animals could inherit traits that favor their survival in specific climatic conditions. The adaptation of small ruminants to different thermal environments is determined by an elaborate network of genes with specific genome-wide DNA markers improving toleration to excessive heat. Therefore, genetic identification and analysis of thermotolerance genes should be applied as markers in breeding programs.
... When hormonal changes cannot regulate body water balance, further changes associated with water deprivation can occur, such as decreased plasma and total body water volume, greater hemoconcentration, increased concentrations of plasma metabolites, electrolytes, and kidney excretory products, and reduced feed intake and energy metabolism [7][8][9][20][21][22][23]. Severe dehydration may also cause oxidative stress, inflammatory responses, reduced resistance to disease, and deteriorated health conditions [17,24]. The capacity of livestock to regulate body water balance and metabolic activity varies among breeds [19,25]. Many small ruminant breeds in extreme environments have excellent resilience to water restriction compared with others in different regions of the world [2,6,15,19,25]. ...
... The capacity of livestock to regulate body water balance and metabolic activity varies among breeds [19,25]. Many small ruminant breeds in extreme environments have excellent resilience to water restriction compared with others in different regions of the world [2,6,15,19,25]. ...
... Creatinine is produced in muscles and excreted by the kidneys in proportion to muscle mass and the rate of proteolysis [55]. However, with water restriction, the transfer function of the kidney is altered [16], resulting in slower glomerular filtration and higher reabsorption [25,56]. Plasma urea N concentration has a high negative correlation with glomerular filtration rate, and urea N in the urine primarily originates from filtrate urea N with a substantial amount of urea secretion in the tubules of nephrons by urea transporters [57]. ...
Different hair sheep breeds originated from diverse climatic regions of the USA may show varying adaptability to water deprivation. Therefore, the objective of this study was to assess the effects of restricted availability of drinking water on blood characteristics and constituent concentrations in different breeds of hair sheep from various regions the USA. For this study, 45 Dorper (initial age = 3.7 ± 0.34 yr), 45 Katahdin (3.9 ± 0.36 yr), and 44 St. Croix (2.7 ± 0.29 yr) sheep from 45 farms in 4 regions of the USA (Midwest, Northwest, Southeast, and central Texas) were used. Ad libitum water intake was determined during wk 2 of period one, with 75% of ad libitum water intake offered during wk 2 of period two, and 50% of ad libitum water intake offered for 5 wk (i.e., wk 5–9) in period three. Water was offered at 07:00 or 07:30 h, with blood samples collected at 08:00 and(or) 14:00 h in wk 1, 2, 3, 4, 8, and 9 for variables such as hemoglobin and oxygen saturation and wk 2, 4, 6, 8, and 9 for concentrations of glucose and other constituents. The blood oxygen concentration at 08:00 h was 4.86, 4.93, and 5.25 mmol/L in period one and 4.89, 4.81, and 5.74 mmol/L in period three for Dorper, Katahdin, and St. Croix, respectively (SEM = 0.160; p = 0.001). Blood oxygen at 14:00 h was 4.37, 4.61, and 4.74 mmol/L in period one and 4.66, 4.81, and 5.46 mmol/L in period three for Dorper, Katahdin, and St. Croix, respectively (SEM = 0.154; p = 0.003). St. Croix were able to maintain a higher (p < 0.001) blood oxygen concentration than Dorper and Katahdin regardless of water availability. The pattern of change in blood concentrations with advancing time varied considerably among constituents. However, concentrations of glucose (55.3 and 56.2 mg/dL; SEM = 0.84), lactate (24.1 and 22.5 mg/dL; SEM = 0.79), total protein (7.08 and 7.17 g/dL; SEM = 0.0781), and albumin (2.59 and 2.65 g/dL in wk 2 and 9, respectively; SEM = 0.029) were similar (p > 0.05) between periods one and three. Conversely, concentrations of cholesterol (56.2 and 69.3 mg/dL; SEM = 1.33) and triglycerides (28.6 and 34.5 mg/dL in wk 2 and 9, respectively; SEM = 0.98) were greater (p < 0.05) in period three vs. 1. In conclusion, water restriction altered almost all the blood variables depending upon severity and duration of restriction, but the hair sheep breeds used from different regions of the USA, especially St. Croix, displayed considerable capacity to adapt to limited drinking water availability.
... Among the livestock species, small ruminants especially goats are considered to be more tolerant to extreme variations in climatic conditions (Darcan and Silanikove, 2018). Goat farming serves as an important source of income especially for the rural community (Silanikove, 2000). Higher populations of goats are located in arid and semi-arid regions of tropical and sub tropical countries reflecting its adaptability to harsh tropical environment (Kumar and Roy, 2013). ...
... Goats can efficiently utilize poor quality feed stuffs and convert into products of high economic returns. Furthermore they have the ability to reduce their metabolic rate in order to conserve energy during scarcity condition (Silanikove, 2000). Goats also possess the ability to perform better in harsh environment, when compared to other livestock species, because of their potential to utilize feed stuffs which cannot be consumed by other ruminants (Silanikove, 1997 andRahimi et al. 2021). ...
... Goats also possess the ability to perform better in harsh environment, when compared to other livestock species, because of their potential to utilize feed stuffs which cannot be consumed by other ruminants (Silanikove, 1997 andRahimi et al. 2021). Goats have superior thermo regulatory mechanism and can also cope with water scarcity in addition to low methane emission (Silanikove, 2000). ...
An attempt to comprehend the status of factors driving adoption of technologies with specific reference to goat farming in the changing climatic scenario was studied through narrative literature review and meta-analysis. Review of past studies suggests that the extension system suffers with limitations of financial and man-power resources. Additionally, farmers have minimal access to the scientific advancement in the field of livestock production. Further, the meta-analysis revealed that the farmers had knowledge of 47% on technologies that has potential to mitigate the effects of climate change on goats. The health, feeding, breeding and housing practices had an adoption level of 31, 40, 58 and 70% respectively. While the extent of adoption of specific practices such as ectoparasitic control, deworming and vaccination ranged from 24 to 48%. The high climatic risk prone areas had low overall adoption rate on comparing to low risk prone areas even though the knowledge on goat farming practices / technologies were vice versa. This study identified that knowledge of farmers, access to extension services and individuals’ economic motivation had larger effect on adoption with a population effect size of 0.69, 0.52 and 0.52, respectively. The climate risk proneness moderate the relationship of access to extension services and education with adoption. Thus, meta-analysis suggests that targeting farmers with better education and having contacts with extension agents with climate risk mitigating technologies may provide earlier benefits. Added the livestock extension system plays a significant role in technology transfer activities in goat farming, which needs to adapt with investments, human resources, research on climate resilient technology transfer activities and capacity building programs. Such an approach might help to deliver the technical know-how on climate resilient technologies and skills to farming community to mitigate the negative effects of climate change.
... Goat farming is one of the important enterprises, supporting rural employment and providing a steady income for farmers in comparison to other livestock enterprises. Goats had the ability to cope with climate change by expressing adaptive strategies as compared to other ruminants (Silanikove, 2000) because of their low body mass, low metabolic requirements, ability to reduce metabolism, skillful grazing behavior and effective urea cycling (Silanikove and Koluman, 2015). The main climatic variables that impose an impact on goats are high ambient temperature, high direct and indirect solar radiation, wind speed and humidity (Silanikove, 2000). ...
... Goats had the ability to cope with climate change by expressing adaptive strategies as compared to other ruminants (Silanikove, 2000) because of their low body mass, low metabolic requirements, ability to reduce metabolism, skillful grazing behavior and effective urea cycling (Silanikove and Koluman, 2015). The main climatic variables that impose an impact on goats are high ambient temperature, high direct and indirect solar radiation, wind speed and humidity (Silanikove, 2000). Temperature humidity index (THI), a reliable indicator of stressful thermal environment conditions could be used for measuring the heat load in animals. ...
... However, Attappady black goats were having low heat stress. According to Silanikove (2000), the increase in breath rate above 40 could be called panting and the increase in panting could be due to the increased respiratory evaporation for body cooling purposes. ...
The present study was undertaken to investigate the association of the temperature-humidity index with physiological, biochemical and behavioural responses in Malabari, crossbred and Attappady black goats of Kerala, India. A positive correlation was noticed between in-house temperature (IT) and temperature-humidity index (THI) with respiration rates, rectal temperatures, heart rate and skin temperature levels of breeds at 2.00 PM and 5.00 PM. Biochemical and endocrines parameters, blood gases and electrolytes were analysed during the 2nd, 32nd and 60th day of the study. Alterations in physiological parameters were more significant in Malabari goats. However, a negative correlation was observed between in-house relative humidity and all physiological parameters during all the different times. Behavioural patterns were influenced by increased IT and THI and the breeds spent more time in standing position during heat stress. A significant difference was observed within the study period in the pO2, Na⁺, HCO3⁻ and blood pH. A significant difference was observed between the breeds for K⁺, Cl⁻ and HCO3⁻ levels. A significantly higher glucose level on the 32nd day and a lower total cholesterol level in the latter half of the experimental period were noticed in Malabari and crossbred. Mean total protein levels of all the breeds were significantly increased on the 32nd day. Increased GGT levels were observed in the first half of the experimental period in all breeds. Higher cortisol levels in Malabari and crossbred could be estimated in the first half of the experiment. Although Malabari showed higher T3 levels on the 32nd day compared to other breeds, within the breeds no significant difference in T3 levels could be noticed. However, significantly higher T4 values were recorded on the 32nd day and 60th day only in Crossbred breeds when the IT and THI were high. Thus it has been shown that heat stress was affecting the physiology, metabolism and behaviour of breeds. The increase in respiratory rate and rectal temperature were the first signs of heat stress in these breeds. The physiological manifestations of stress were the greatest for Malabari goats and the least for Attappady black.
... Global warming is currently becoming a reality. Goats that can live in harsh climates have advantages in their adaptation to such areas (Silanikove, 2000). This ability is multi-faceted; low body weight and metabolic requirements can be considered an important advantage in terms of minimizing maintenance and water requirements in areas where water resources and the number of nutrients are limited (Silanikove, 2000). ...
... Goats that can live in harsh climates have advantages in their adaptation to such areas (Silanikove, 2000). This ability is multi-faceted; low body weight and metabolic requirements can be considered an important advantage in terms of minimizing maintenance and water requirements in areas where water resources and the number of nutrients are limited (Silanikove, 2000). Goats, especially local breeds, have adapted to large climate changes and insufficient food sources and can easily survive in such regions. ...
Background: The hair goat of Anatolia is a breed that has adapted to rugged and mountainous areas and is known to be very resistant to diseases. As the world faces the problem of climate change, we believe that knowing the hematological characteristics of hair goats will provide great benefits for goat breeding. Objectives: This study was performed to determine possible differences in the blood parameters of adult (male and female) hair goats during and out of the breeding season. Methods: For this purpose, blood samples were taken from clinically healthy adult male and female hair goats (n=36, 3-4 years old) in the spring and autumn seasons. Regarding the whole blood, white blood cell (WBC), red blood cell (RBC), hemoglobin (Hb), hematocrit (Hct), mean red blood cell volume (MCV), mean red blood cell hemoglobin (MCH), average red blood cell hemoglobin concentration (MCHC) and red blood cell distribution width (RDW) values were determined. Results: In the study, MCV values in males were not significantly (P≥0.05) different between spring and autumn, while all other parameters showed significant differences (P≤0.05). In females, WBC, RBC, Hb, Hct, and RDW blood values were higher in the autumn (estrus period) than in the spring (anestrus period), and the differences were found to be significant (P≤0.05). Comparing males and females between the estrus and anestrus seasons, WBC and MCHC were found to be significantly different (P≤0.05) between males and females in May. In contrast, the difference between other parameters was not significant. In October (estrus season), the MCV value was not significantly different between males and females; however, all other parameters were significantly different (P≤0.05). Conclusion: As a result, there were significant differences in hematological parameters of hair goats based on gender and the breeding season.
... 3. Lying/standing time: It is one of the main behavioural responses of animals to cope with heat stress. In many studies, it has been reported that increased standing and decreased bedtime in animals are associated with higher ambient temperatures (Silanikove, 2000;Darcan et al., 2008;Hienicke et al., 2020). Cows tend to stand more at noon as the temperature increases during the day (Allen et al. 2015;Hienicke et al. 2020). ...
... It is an early warning indicator of the onset of heat stress and the animal's body can increase the respiratory rate to dissipate excess heat (Ji et al., 2020). Silanikove (2000) reported that RR is a good way to cool the brain under heat stress. Valente et al. (2015) reported an increase in RR when cattle were exposed to high temperature stress in their study in Angus, Nellore and Sahival breeds. ...
Livestock plays an important role in the global economy. Climate change directly affects animal production. Therefore, animal food security is under threat in many parts of the world. In addition, more than one stressor affects animals directly or indirectly. Among these stresses, heat stress seems to be the most important factor that negatively affects livestock production. Among the environmental variables affecting animals, heat stress is one of the factors that complicates animal production in many parts of the world. Genotypic and phenotypic characteristics are used to determine heat stress in cattle. The response of livestock to heat stress varies according to species, genetic potential, life stage, management or production system and nutritional status. Identifying region-specific, climate-and heat-tolerant animals is critical for sustainable animal production. For this reason, animals must have the genetic ability to resist heat stress in order to sustain animal production under extreme climatic conditions. It is important to determine the responses of animals to stress in order to identify animals with superior genetic characteristics that can be economically beneficial. Adaptation mechanisms of animals against stress may vary according to their morphological, behavioural and genetic capacities. In this study, behavioural and physiological responses of cattle at extreme temperatures were evaluated. In order to determine these responses to stress in animals, factors such as feed-water consumption, lying-standing times, sweating rate, respiration rate, and rectal temperature were investigated.
... Las cabras son consideradas consumidores intermedios, por lo tanto: (i) Son muy selectivos, (ii) tienen una actividad eficiente de la masticación y del rumen; (iii) son capaces de aprovechar tanto dietas ricas en fibra por una ampliación considerable del aparato digestivo, como así también en concentrados, (iv) pueden tolerar el bajo consumo de agua, (v) elevada secreción de saliva, (vi) alta superficie de absorción de gran parte del epitelio del rumen, que protegen al animal del riesgo de acidosis (Silanikove, 2000). Debido a estas características, las cabras pueden adaptarse a una amplia gama de condiciones de alimentación ya que modifican su conducta alimenticia de acuerdo con la disponibilidad de forrajes o concentrados, siendo más versátiles que otros rumiantes domésticos (Rapetti & Bava, 2008). ...
... A pesar de que la cabra, como animal rumiante que es, necesita un aporte diario de fibra para el correcto funcionamiento del rumen, no existen recomendaciones claras sobre los niveles de fibra a considerar (Calsamiglia et al., 2009). Así mismo, el propio comportamiento ingestivo de la cabra (Silanikove, 2000;Rapetti & Bava, 2008), permitió que el consumo total de MS en ambos tratamientos no difiera. Si bien las densidades energéticas de los ingredientes no fueron determinadas o estimadas desde la FDA, los efectos observados sobre la condición corporal, podrían deberse a una movilización de reservas corporales, debido al menor consumo energético en T1. ...
El objetivo del siguiente trabajo fue evaluar el efecto de la incorporación de Gleditsia triacanthos (Acacia negra) sobre el consumo total de MS, de sus fracciones y de la producción y composición química de la leche en cabras lactantes. Se emplearon 16 cabras en un periodo experimental de 12 semanas: 2 de acostumbramiento y 10 de ensayo. Se asignaron dos tratamientos: uno a base de heno de alfalfa (HA) (200 g/día/animal), más grano de maíz entero (GME) (500 g/día/animal) (T0) y otro: heno de pastizal natural (HPN) (100 g/día/animal), GME (400 g/día/animal) y fruto de acacia negra (FAN) (200 g/día/animal) (T1). Se determinó el consumo individual aparente a campo, el de GME (T0) y de FAN + GME (T1). Se registró el consumo de cada corral de HA (T0) y de HPN (T1). Fue estimado el consumo de fibra (FDN), de proteína bruta (PB) y energía metabolizable (CTEM) de cada tratamiento. Se determinó la condición corporal (CC), la producción láctea individual (PL) y la composición química de la leche. El GME fue consumido en su totalidad en ambas dietas y en T1 la ingesta de FAN fue de 160 g/animal/día. En el corral del T1 el consumo de HPN fue menor (p<0,05). El consumo total de MS, de pastizal natural, de FDN, PB y EM no arrojaron diferencias (p>0,05) entre tratamientos. Las cabras de T1 verificaron menor CC (p<0,05). Una regresión lineal entre CTEM y la CC (p=0,008) corroboró una relación moderadamente fuerte (0,658). La PL no difirió (p>0,05) entre tratamientos. La grasa butirosa (p=0,094), la PB y lactosa (p<0,05) fue mayor en T1 que en T0. La inclusión del fruto de Gleditsia triacanthos en cabras en lactancia mejoró el porcentaje de proteína y lactosa, sin modificaciones en la PL en relación a la dieta testigo.
... Desert Beduin goats, even lactating, can reach watering up to once every four days. Rumen functions as a water reservoir and is rapidly filled when animals can drink (Silanikove 2000). Large amount of water rapidly ingested is stored in the rumen and utilized until the next hydration bout, but rapid absorption of hypotonic fluid could be hazardous, due the osmotic gradient with blood (Silanikove 1994). ...
... Large amount of water rapidly ingested is stored in the rumen and utilized until the next hydration bout, but rapid absorption of hypotonic fluid could be hazardous, due the osmotic gradient with blood (Silanikove 1994). Several mechanisms allow to retain water in the body avoiding intoxication with consequent haemolysis, such as increased Na + retention within the rumen, large water flux and recirculation between gut blood and rumen, via increased secretion of hypotonic saliva, while diuresis is reduced (Silanikove 1989(Silanikove , 2000. Camels, in addition, have erythrocytes extremely resistant to haemolysis (i.e. with low osmotic fragility) (von Engelhardt et al. 2006). ...
Animals can sense their changing internal needs and then generate specific physiological and behavioural responses in order to restore homeostasis. Water-saline homeostasis derives from balances of water and sodium intake and output (drinking and diuresis, salt appetite and natriuresis), maintaining an appropriate composition and volume of extracellular fluid. Thirst is the sensation which drives to seek and consume water, regulated in the central nervous system by both neural and chemical signals. Water and electrolyte homeostasis depends on finely tuned physiological mechanisms, mainly susceptible to plasma Na⁺ concentration and osmotic pressure, but also to blood volume and arterial pressure. Increases of osmotic pressure as slight as 1–2% are enough to induce thirst (“homeostatic” or cellular), by activation of specialized osmoreceptors in the circumventricular organs, outside the blood-brain barrier. Presystemic anticipatory signals (by oropharyngeal or gastrointestinal receptors) inhibit thirst when fluids are ingested, or stimulate thirst associated with food intake. Hypovolemia, arterial hypotension, Angiotensin II stimulate thirst (“hypovolemic thirst”, “extracellular dehydration”). Hypervolemia, hypertension, Atrial Natriuretic Peptide inhibit thirst. Circadian rhythms of thirst are also detectable, driven by suprachiasmatic nucleus in the hypothalamus. Such homeostasis and other fundamental physiological functions (cardiocircolatory, thermoregulation, food intake) are highly interdependent.
... In ruminants, there is a loss in productivity as animals pass through the acute phase and return to productivity as they undergo acclimation to the stress (Collier et al. 2006). The species specific difference in HSP70 is due to variation in thermal tolerance (Silanikove 2000, Hightower et al. 1999. ...
... Especially, HSPA1A mRNA showed higher expression during winter in heat-adapted breeds (Sirohi and Barbari) compared to cold-adapted breeds (Gaddi and Chegu) again re-iterating the fact that heat-adapted breeds are also equal prone to cold stress as cold-adapted breeds to heat stress (Banerjee et al. 2014). There are also considerable points to leverage our findings that portrayed differences between breeds with regard to heat stress in ruminants which has the ability to subdue the metabolism thereby negatively influencing the body heat production and augmenting its effective dissipation (Silanikove 2000, Kadzere et al. 2002. It has been suggested that the expression of Hsp70 was significantly higher during the summer season as compared to the winter in tropical region goats, which might play an important role in thermal stress tolerance against harsh environmental conditions (Dangi et al. 2012). ...
Heat shock proteins (HSPs), also known as molecular chaperons are prominent stress markers. Heat shock proteins consist of highly conserved protein expressed at the time of stress, and play an important role in adaptation to the environmental stress. Although, the expression pattern of HSP70 gene is species and breed specific, variations in adaptation and thermal tolerance is due to the nature of environment and adaptive capacity of a species. The present study was conducted to evaluate the adaptive capability of different goat (Capra hircus) breeds, i.e. Jamunapari, Barbari, Jakhrana and Sirohi under peak dry summer. The targeted gene HSP70 (HSPA6) was evaluated for this purpose using specific primers. The expression of HSP70 gene and protein was estimated by RT PCR and ELISA kits respectively. The expression of HSP70 gene was found lowest in sirohi breeds implying that this breed was more adapted followed by Jakhrana, Barbari and Jamunapari during peak summer season. Whereas, the level of HSP70 protein in blood was significantly higher in Jamunapari, followed by Barbari, Jakhrana and lowest in Sirohi. These results indicated that, during adverse climatic stress the quantum of expression (HSP70 gene and protein) was more in Jamunapari. It is concluded that Sirohi breed is better adapted to heat stress than Jamunapari, Jakhrana and Barbari and HSP70 may be a potential molecular biomarker in the future for selection of climate resilient animals.
... Dê có khối lượng nhỏ, nhu cầu thức ăn ít nên không đòi hỏi diện tích chuồng trại và đồng cỏ lớn so với trâu bò. Thêm vào đó khả năng chống chịu với điều kiện nắng nóng (HTa) của dê tốt hơn so với trâu, bò (Silanikove, 2000). Vì vậy, dê có thể được xem là vật nuôi thích hợp trong điều kiện biến đổi khí hậu hiện nay tại Việt Nam. ...
... West (1994), chỉ số THI ở bò với giá trị tương đương 70 hoặc nhỏ hơn bò không bị stress nhiệt, lớn hơn 70 bò bị stress nhiệt và THI trên 80 bò bị stress nhiệt nghiêm trọng. Tóm lại, ở động vật nhai lại dê và cừu có khả năng chịu được stress nhiệt tốt hơn so với bò (Silanikove, 2000). ...
Mục tiêu của thí nghiệm là đánh giá ảnh hưởng của nước muối lên khả năng tăng trọng và năng suất sữa của dê. Thí nghiệm được bố trí hoàn toàn ngẫu nhiên với 04 nghiệm thức (NT) và 05 lần lập lại trên 20 dê thịt lai Boer (thí nghiệm 1) và 20 dê sữa lai Saanen (thí nghiệm 2) gồm: NT đối chứng (ĐC, nước ngọt), 3 nghiệm thức nước mặn là các nồng độ nước biển pha loãng: 0,50; 1,00 và 1,50% (NT5, NT10 và NT15). Kết quả thí nghiệm 1 cho thấy lượng thức ăn tiêu thụ (DMI) giảm và lượng nước uống (WI) tăng dần khi tăng dần nồng độ muối trong nước uống. Trọng lượng, tăng trọng, tần số hô hấp và nhiệt độ trực tràng của dê không có sự khác biệt giữa các nghiệm thức (P>0,05). Tuy nhiên, ở thời điểm 15:00 giờ, dê ở NT15 giảm tần số hô hấp và tăng nhiệt độ trực tràng so với NT ĐC. Kết quả thí nghiệm 2 cho thấy DMI, trọng lượng, năng suất sữa không khác biệt giữa các NT (P>0,05). WI của dê tăng khi uống nước muối có nồng độ...
... Lespedeza is lower in nutritive value than alfalfa because of higher concentrations of total fiber, lignin, and bioactive condensed tannins (CT) [1,3]. However, studies over the last [15][16][17][18][19][20] years have demonstrated the effectiveness of this forage to reduce gastrointestinal parasitic infections and prevent bloat in ruminants due to the presence of CT [1,4]. This has contributed to a renewed interest in the use of lespedeza as a medium-quality warm-season nutraceutical forage for livestock in different parts of the world [1,5]. ...
... Goats and sheep differ in many ways when fed tannin-rich diets and forage, including the level of feed intake, feeding behavior, nutrient digestibility, and growth performance. Compared with sheep, due to their evolutionary lineage as browsing animals, goats are considered more tolerant and adaptive to forage and browse plant species containing high concentrations of CT [16,17]. It has been reported that CT in lespedeza did not affect dry matter (DM) intake in goats but reduced DM intake and digestibility in sheep [18]. ...
Twenty-four Alpine doelings, initial 25.3 ± 0.55 kg body weight (BW) and 10.4 ± 0.11 mo of age, and 24 Katahdin ewe lambs, 28.3 ± 1.02 kg BW and 9.6 ± 0.04 mo of age, were used to determine effects of dietary inclusion of Sericea lespedeza (Lespedeza cuneata) hay on feed intake, digestion, growth performance, energy metabolism, and ruminal fermentation and methane emission. There were four periods, the first three 42 days in length and the fourth 47 days. Diets consumed ad libitum contained 75% coarsely ground hay with alfalfa (ALF), a 1:1 mixture of ALF and LES (ALF+LES), and LES (10.0% condensed tannins; CT). The intake of dry matter (DM) tended to be greater (p = 0.063) for Katahdin than for Alpine (4.14 vs. 3.84% BW; SEM = 0.110). The dry matter intake was similar among the diets (3.97, 4.10, and 3.89% BW for ALF, ALF+LES, and LES, respectively; SEM = 0.134). The digestion of organic matter (75.3, 69.3, and 65.5%; SEM = 0.86), neutral detergent fiber (61.7, 50.5, and 41.4%; SEM = 1.49), and nitrogen (78.8, 66.9, and 50.8% for ALF, ALF+LES, and LES, respectively; SEM = 0.92) decreased as the dietary concentration of lespedeza increased (p < 0.05). However, there was an interaction (p < 0.05) between the breed and diet in nitrogen digestion, with a greater value for goats vs. sheep with LES (54.4 vs. 47.3%; SEM = 1.30). The digested nitrogen intake decreased markedly with the increasing quantity of lespedeza (38.0, 27.5, and 15.7 g/day for ALF, ALF+LES, and LES, respectively; SEM = 1.26). The average daily gain was greater for Katahdin than for Alpine (p < 0.001; 180 vs. 88 g, SEM = 5.0) and ranked (p < 0.05) ALF > ALF+LES > LES (159, 132, and 111 g, respectively; SEM = 6.1). The ruminal methane emission differed (p < 0.05) between animal types in MJ/day (1.17 and 1.44), kJ/g DM intake (1.39 and 1.23), and kJ/g ADG (18.1 and 9.8 for Alpine and Katahdin, respectively). Regardless of the period and animal type, diet did not impact methane emission in MJ/day or relative to DM intake, BW, or ADG (p > 0.05). The digestible and metabolizable energy intakes, heat production, and retained energy were not affected by diet (p > 0.05). In conclusion, future research should consider the marked potential effect of CT of forages such as lespedeza on nitrogen digestion and associated effects on protein status and other conditions that may be impacted.
... In the current meta-regression, studies conducted by Oliveira et al. [38] (n = 34) and Costa et al. [34] (n = 47) evaluated sheep-fed diets containing different levels of metabolizable energy, and this difference in diet quality could promote a longer MRT in the GIT of these sheep, consequently resulting in a larger GITwps compared with the other studies carried out with sheep. Another explanation for our results could be that goats have a smaller proportion of the gut in relation to BW, leading to rapid movement of digesta from the rumen and throughout the gastrointestinal tract [75]. On the other hand, for the non-linear equations, a more consistent and evident effect of species was observed, modifying the GITwps:BW relationship only at the intercept, with sheep showing higher tract content compared with goats (Table 3; Equation (9)). ...
The gastrointestinal tract (GIT) wet pool size (GITwps) refers to the total amount of wet contents in GIT, which in small ruminants can reach up to 19% of their body weight (BW). This study aimed to develop models to comprehensively predict GITwps in small ruminants using a meta-regression approach. A dataset was created based on 21 studies, comprising 750 individual records of sheep and goats. Various predictor variables, including BW, sex, breed, species, intake level, physiological states, stages and types of pregnancy, dry matter intake, and neutral detergent fiber intake (NDFI), were initially analyzed through simple linear regression. Subsequently, the variables were fitted using natural logarithm transformations, considering the random effect of the study and residual error, employing a supervised forward selection procedure. Overall, no significant relationship between GITwps and BW (p = 0.326) was observed for animals fed a milk-based diet. However, a strong negative linear relationship (p < 0.001) was found for animals on a solid diet, with the level of restriction influencing GITwps only at the intercept. Furthermore, the prediction of GITwps was independent of sex and influenced by species in cases where individuals were fed ad libitum. Pregnant females showed a noticeable reduction in GITwps, which was more pronounced in cases of multiple pregnancies, regardless of species (p < 0.01). The composition of the diet was found to be the primary factor affecting the modulation of GITwps, with NDFI able to override the species effect (p < 0.0001). Overall, this study sheds light on the factors influencing GITwps in small ruminants, providing valuable insights into their digestive processes and nutritional requirements.
... Kacang goat has a high adaptability to local natural conditions, high reproduction rate and able to live with all available feed conditions in field. The characteristics of Kacang goat has a relatively small body size and small head, short legs, eats stand forward straight and generally single white, black, brown, or a combination colour and the male and female goats have two short horns [2] [3]. Currently, development of Kacang goat business is relatively stagnant due to the presence of superior goats entering the Indonesian region with higher productivity, such as Peranakan Etawa (PE) and Peranakan Boer goats. ...
A study aimed about examining the correlation between dry matter consumption, dry matter digestibility of feed and final body weight was carried out on local goats (Kambing Kacang) fed on basal feed of sugarcane top leaf (STL) and urea molasses block containing different percentages of coffee husk waste flour (UMB-CHWF) has been carried out for 90 days of observation using a completely randomized design. This study used 16 young male goats aged 6 months and fed on 4 types of feed treatment, namely: P1 (fed on STL and UMB without CHWF), P2 (fed on STL and UMB contained 10% of CHWF), P3 (fed on STL and UMB contained 20% of CHWF) and P4 (fed on STL and UMB contained 30% of CHWF. The results showed that combination of STL and UMB feed containing 20% CHWF showed a very close positive correlation (coefficient correlation was 0.79, 0.63 and 0.93, respectively) between the increase in amount of dry matter consumption, dry matter digestibility and final body weight better than other treatments. However, the percentage of CHWF in UMB increased to 30% percent did not changes in totol amount of dry matter consumption, dry matter digestibilityor final body weight on Kambing Kacang after weaning period.
... Goats display a larger variability than the other species and, in the case of the Balearic Islands, they show a decrease in length during the MBA and a size increase during the LBA. It is well-known that goats can easily adapt to their environment (Dahl and Hjort, 1976;Silanikove, 2000). Consequently, the observed size fluctuations could be related to a better adaptation of this species. ...
In this paper, measurements of 2.012 bone remains from four different domestic species (sheep, goats, cattle and pigs) originating from 33 Bronze Age archaeological sites from the Balearic Islands, mainland Iberia, southern France and Sardinia, and spanning about 2500 years (3700-700 cal. BCE) have been compared. The results show that a decrease in animal size occurred in the Balearic Islands during the Bronze Age. It was not a local phenomenon but rather was a general pattern that happened in different territories. Yet it was more marked on the islands. The evidence shows that the four analyzed species were not affected in the same way and it was a nonlinear phenomenon. Indeed, during the Late Bronze Age some archaeological sites from the Balearics had taller caprines compared with the other contemporaneous places, also on the continent. A multi-factor explanation for these fluctuations is proposed in this paper, showing that animal sizes generally decreased during late prehistory -especially cattle- and this process could reflect different factors such as a combination of limited feeding, increased human pressure and endogamy.
... This therefore necessitates an analysis of more parameters including energy and mineral contents of the browser leaves to determine how best to supplement them. That the weight loss was not greater may be attributed to the fact that goats have also been reported to be able to minimise maintenance energy requirements during periods of low energy intake (Silanikove, 2000). ...
This study investigated the seasonal effects of Rhus lancea and Celtis africana leaves on preference, intake, weight, and serum metabolites in South African indigenous, mature, male goats. Twelve mature, male goats weighing 34 ± 5.9 kg (mean ± SD) were randomly allocated to two groups of six and kept in metabolic crates for periods of 21 days in October 2015 and March, May, and August of 2016. A browser diet of R. lancea and C. africana and a control diet (lucerne and concentrates) were randomly allocated to each group. Measurements taken included nutritional composition of browse per season, and browse preference, intake, weight changes, and serum metabolites in the goats. The acid detergent fibre (2436%) and neutral detergent fibre (26.9-70.4 %) in R. lancea over the months were greater than in C. africana (50.3-53.2% and 49.4-55.4%, respectively). In the preference study, the goats preferred C. africana more in October (51.2 vs 48.8%), March (51.4 vs 48.6%), and May (54.3 vs 45.7%). Goats on the browser diet lost weight in March, May, and in August whereas those on the control diet gained weight. The serum urea concentration of goats consuming browser diets in May and August (1.8-3.3 mmol/l) was lower than the normal range, consistent with animals failing to derive their protein requirements from the diet. Goats prefer to browse C. africana more than R. lancea. The study also indicated the need for supplementation to meet maintenance requirements in animals fed R. lancea and C. africana.
... In many parts of the world, goats are preferred by animal producers due to better tolerance and performance under harsh environments, especially in predominantly semi-arid regions (Silanikove 2000). In Sudan, goats may be classified into four major types: Nubian goats, Desert goats, Nilotic goats and Tagger (Mason and Maule 1960). ...
Three yearling uncastrated males of Sudan Nubian goatsranging in weight between 14 and 20 kg were used in a 3x3 latin squaredesign experiment with the objective of studying the effects of feed andwater restriction on dry matter intake (DMI), water intake, digestibility ofnutrients, rumen components, blood urea-N (BUN), rectal temperatureand respiration rate. The experiment consisted of three treatments:Adlibitum feed and water, feed restricted to 50% of adlibitum level withadlibitum water, water restricted to 50% of adlibitum level with adlibitumfeed. The results revealed no significant treatment effects on water intake,urine volume, rectal temperature and respiration rate. However, DMIdiffered significantly between treatments. The adlibitum provision ofwater resulted in insignificant higher water intake compared with theother two treatments. Rectal temperature was higher in water restrictedgoats than in feed restricted goats, whereas respiration rate decreasedinsignificantly with both feed and water restrictions. Feed and waterrestrictions had no effect on the digestibility coefficients of the variousnutrients. Water restricted goats showed, however, different trends exceptfor ether extract digestibility which tended to decrease. Treatment had nosignificant effect on the total digestible nutrients (TDN) values. The TDNtended to be higher with water restriction. There was no significanttreatment effect on rumen pH, ammonia-N (NH3 -N) and BUN. Feed andwater shortage did not significantly affect digestibility of the proximatecomponents but tended to slightly affect rumen metabolites, BUN,respiration rate and rectal temperature.
... increases in the levels of urea and creatinine during prepartum period compared with the day of lambing and post-partum periods may be due to the increased in cortisol concentrations that increases the catabolism of protein in the body. This result was in agreement with that found by (44), and Taghipour et al., (45) who stated that the decrease in serum blood urea nitrogen around parturition may be associated with the decline of feed intake due to stress and hormonal changes during lambing. Ozpinar et al., (38) explained the reason of creatinine rises during prepartum period to the using of creatinine in muscle tissue of fetus as well as mother. ...
... increases in the levels of urea and creatinine during prepartum period compared with the day of lambing and post-partum periods may be due to the increased in cortisol concentrations that increases the catabolism of protein in the body. This result was in agreement with that found by (44), and Taghipour et al., (45) who stated that the decrease in serum blood urea nitrogen around parturition may be associated with the decline of feed intake due to stress and hormonal changes during lambing. Ozpinar et al., (38) explained the reason of creatinine rises during prepartum period to the using of creatinine in muscle tissue of fetus as well as mother. ...
... Padronização do teste de desenvolvimento larvar (TDL) para diagnóstico da resistência anti-helmíntica em Haemonchus contortus Introdução A produção de pequenos ruminantes desempenha papéis diferentes e importantes de acordo com as regiões brasileiras. Em comparação aos bovinos, os ovinos e caprinos são amplamente adaptados a condições de clima variado, além de consumirem menor quantidade de alimentos em razão do menor tamanho corporal (SILANIKOVE, 1997;2000;MARKOS, 2006). Esses fatores permitem fácil integração dos pequenos ruminantes a diversos sistemas de produção. ...
Os estudos com isolados de H. contortus indicaram que o TDL foi capaz de detectar a resistência parasitária para os principais grupos de anti-helmínticos disponíveis no Brasil. Os isolados resistentes apresentaram valores de CIs mais elevados do que os isolados susceptíveis. A maioria dos FR gerados demonstrou que o teste foi capaz de distinguir isolados susceptíveis e resistentes. Para o monepantel, os resultados indicaram o uso do produto comercial (Zolvix®) para a distinção entre isolados com extremos de resistência, entretanto, tal situação ainda será mais bem investigada por nosso grupo de pesquisa. A adaptação do teste para placas de 96 poços resultou em economia de, pelo menos, 29,1% do custo. O valor de R$ 8,26 para a realização de um diagnóstico de resistência, a partir do envio de amostras fecais para o teste, se mostra bastante acessível para os criadores. O TDL mostrou-se confiável para o uso na rotina laboratorial e sua validação com amostras de campo permitirá um controle parasitário mais racional e guiado em ovinos e caprinos, de modo a retardar o desenvolvimento da resistência e a preservar as classes químicas.
... Physical and endocrine reactions to stress are catabolic because threatening situations necessitate quick action. That is, they aid in the mobilization of the organism's energy reserves through altering carbohydrate, lipid, electrolyte, and water metabolism (45). The hypothalamic-pituitary-adrenal axis secretes hormones that have a broad and long-lasting effect on the organism. ...
... Increasing respiratory rate, panting, increasing sweating rate, changes in endocrine function, and reducing metabolic rate are the thermoregulation mechanisms used by sheep to maintain their body temperature in heat-stressed environments [40,41]. Morphological characteristics like body size and shape influence the thermoregulatory mechanisms of farm animals under heat stress [42]. Berihulay et al. [35] and Mwacharo et al. [43] reported that taller animals dissipate more heat with lower metabolic rates than animals with short, squat bodies, who gain heat at a slower rate. ...
Indigenous sheep are highly adaptable and widely distributed in different regions of Bangladesh.
They are famous for their tolerance to harsh environmental conditions, low demand for feed, and
disease resistance with minimum or no housing and management facilities. Ample indiscrimi�nate research reports and case studies on the native sheep of Bangladesh have been published.
Nonetheless, a comprehensive review of reproductive and productive performances, as well as
their various morphometric physiognomies and climate resilience capabilities, is lacking. This
review was designed to explore and summarize the available research reports on indigenoussheep
to highlight the gaps and provide an updated database for the future research plan forsustainable
native sheep production in Bangladesh. It covers studies on sheep biodiversity, their adaptabil�ity to the local environment, morphometric features, feeding and nutrition, reproduction and
production performances, diseases and health management, and the problems and prospects
of sheep farming in Bangladesh. Due to the increased demand for animal protein, especially red
meat, the scope of sheep farming increases along with that of other large and small ruminants.
The vital constraints of sheep production in Bangladesh include insufficient feed and fodder sup�ply with its high prices, higher disease occurrence with low or no management practices, kid
mortality, and a poor marketing channel with the lower popularity of sheep meat than goat meat.
Future research would be a prerequisite to measuring the impact of native sheep on household
economies and food security during the year, evaluating the other challenges, and finding out the
possible interventions in the fields of nutrition, reproduction, and health management.
... Different species and varieties of ruminant livestock, however, have developed physiological mechanisms to deal with and reduce negative consequences from this stress factor and others [90]. Livestock suffers from inadequate water intake. ...
Water is essential for food security and animal agricultural productivity, but it is becoming more scarce due to climate change. The interaction between climate change and livestock water resources has received little attention from researchers, despite the significance of small-scale animal husbandry for the rural poor in Africa and the size of the changes that are anticipated to have an impact on smallholder livestock systems. Threats to livestock water are undoubtedly one of the most significant environmental issues that have impacted food security on the continent, given their links to small-scale animal husbandry and the detrimental impacts on productivity. In order to balance the negative effects of climate change scenarios for sustainable animal productivity and contribute to food security through small-scale animal agriculture, the most climate-smart and resilient agricultural water practices and technologies must be used. Changes in rainfall and a decline in the biomass available for grazing and rangelands as a result of water stress brought on by the climate would have the most severe effects. This is due to the rain-fed nature of small-scale livestock farming. The local animal genetic resources are essential for animal productivity and food security in Africa, particularly in areas where livestock water is becoming scarce owing to climate change. Research and development goals on the effects of climate change on livestock water, animal productivity, and food security may need to be reviewed if demands of vulnerable small-scale animal producers are to be successfully addressed in the future decades. It is best to use an interdisciplinary approach to comprehend the relationships between small-scale animal husbandry, food security, and climate change. By navigating the complexities of climate adaptation, small-scale livestock farmers can manage livestock water scarcity by taking adaptation measures that are in line with evolving climate impacts and associated means of implementation based on pertinent and useful knowledge that takes into account a blend of traditional and modern water science. In this paper, an effort is made to close some significant information gaps and shed light on how water-induced stress impacts small-scale animal production, which has an effect on food security.
... The average respiratory rate was 29.3 mov min -1 , which is within the normal range for the species that vary between 24.0 and 36.0 mov min -1 in thermoneutral environments. The animal's respiration rate is influenced by the number of times it is exposed to sunlight and J o u r n a l P r e -p r o o f environmental factors This elevation is due to the high ambient temperature associated with low relative humidity, so the animals used this physiological adjustment to eliminate body heat (Silanikove, 2000) where the animals spend energy in the dissipation of heat by respiration to maintain homeothermy. Physiological control mechanisms in animals have evolved to limit the losses of body fluids, and the elevation of respiratory rate underwater salinity stress for a longer period may reduce the total amount of body water [42]. ...
The present study aimed to evaluate the effect of drinking salinity levels in Lake water on the growth performance, and physiological, and blood constituents of Hararghe-highland lambs. A total of 28 lambs (average IBW of 18±1.18kg) were categorized into four levels of water salinity, namely freshwater (510mg/l TDS), lake Basaka water (LBW; 2600mg TDS/L); lake Basaka water plus 100% TDS of LBW; 5200mg TDS/L) and lake Basaka water plus 200% TDS of LBW; 7900mg TDS/L). The current results suggest that increased total dissolved solid levels in lake water increase the water intake of lambs while not affecting IBW, FBW, AWG, and FCR. Additionally, drinking saline lake with increasing total dissolved solid levels increased rectal temperature and respiration rate and caused a significant (P<0.05) change in the concentrations of glucose, albumin, urea, triglycerides, sodium, AST, and ALT. Some hematological variables and biochemical constituents like creatinine, total protein, cholesterol, chlorides, potassium, magnesium, and calcium showed no significant (P>0.05) differences. In conclusion, Hararghe-highland lambs from Ethiopia could tolerate lake Basaka water with a high salt level (7952mg/L TDS).
... Daramola and Adeloye (2009) highlighted some of the thermotolerant phenotypic characteristics in West African Dwarf goats. Some of these include feeding behaviour that ensures excellent utilisation of poor-quality feed materials (Silanikove, 2000;Kaliber et al., 2016), high disease resistance (Chiejina et al., (2015); Rotimi et al., 2017), good water utilisation capacity (Abioja et al., 2007;, small body size and fleece structure . The adaptive capacity of goats could be observed in changes in morphological, physiological, behavioural, hormonal and molecular levels in the genes. ...
The problem of heat stress (HS) in hot regions of the world is further complicated by climate change and the ensuing global warming. Goats have been a means of sustenance for rural dwellers and people found in resource-poor regions. Goats possess some phenotypic adaptive features that portray them as hardy with ecological adaptability based on anatomical, morphological and physiological characteristics that confer resistance to high environmental temperature. However, goat production is not insulated from the onslaught of climate change. Productivity declines in goats when exposed to HS. There is a rise in mortality and morbidity in heat-stressed goats. Responses of goats to high environmental temperature include perturbations in homeostatic milieu, reduced feed intake and utilization, retarded growth, lowered immunity and reproductive efficiency. It becomes imperative to pay attention to their welfare under the harsh climatic vagaries envisaged in climate change. There are numerous inherent genetic endowments in goats all around the world that could be harnessed for better adaptation. Some of these genetic biomarkers include genes related to heat stress (HSF1, HSP20, HSP70, HSP90), growth (GH, GHR, IGF-1, LEP, LEPR, T3, T4, THR, NOS), reproduction (GnRH, GnRHR, FSHR, LHR, inhibin, PROGR, ESTR), and immunity (TLR2, TLR3, TLR8, TLR10, IL2, IL10). Of all these, HSP70 is the commonest genetic biomarker of thermotolerance in goats. Higher expression of HSP70 mRNA in tissues is an indication of higher thermotolerance.
... The internal microclimate of the vehicle, stocking density, ventilation, moisture build-up, climatic conditions, wind speed, holding time of goats in a stationary vehicle, and wind speed have a major impact on the heat/cold stress during transportation (EFSA Panel on Animal Health and Welfare (AHAW), 2004). The physiological status such as body mass, the metabolic requirement (Daramola and Adeloye, 2009;Silanikove, 2000), breeds (goats with loose skin and floppy ears long hairs, white and brown coat color being more heat tolerant; short-haired black-haired goats more vulnerable (Acharya, Gupta, Sehgal, and Singh, 1995;Daramola and Adeloye, 2009;Mili and Chutia, 2021), and age (kids being more susceptible) are the major factors affecting heat or cold stress in goats. Black color goats were recorded to have a higher rectal temperature, pulse rate, and higher water consumption as compared to goats with white coat color after 12 days of exposure to solar radiation in the summer (Baenyi et al., 2020). ...
Over the years, the handling of goats (loading, transport, unloading, time spent in lairage) prior to slaughter as
well as the slaughter process (stunning, and bleeding) has largely applied to other livestock which impairs the
wellbeing of goats as well as their products due to the difference in behavior among species. Numerous factors
(feeding management, production systems, environmental conditions, and physiological status of the animals)
predispose goats to pre-slaughter stress, resulting in increased stress responses during the transport, lairage, and
slaughter process that influence the meat quality attributes. Goats are more susceptible to pre-slaughter stress
relative to other ruminants. In this review, stress factors relating to goats, indicators as well as management, were
elucidated which will assist producers in making informed decisions on minimizing goat stress for the betterment
of the meat quality and goat industry as a whole.
... had been reported in hot-humid summer conditions of Kerala (Yamin et al., 2022). Although, goat had versatility to cope with adverse climatic conditions through adaptable strategies (Silanikove, 2000;Silanikove and Koluman, 2015), however, they also suffered from heat stress beyond their comfort zone of 13-27 ºC of ambient temperature (Mishra, 2009). The existing goat-shed roof was made up of polymer coated colored galvanized roofing sheet. ...
Black Bengal goats are mainly reared by economically weak farmers under extensive /semi-intensive systems. This breed is very famous for excellent quality meat and high valued skin. At present, phenomenon of gradual shrinkage of grazing land is forcing farmers to adopt goat rearing by intensive management system (IMS). Therefore, assessment of production performance of goats under IMS would help to devise better management for higher profits. Goats managed under IMS revealed that from birth, body weight of animals increased linearly up to 2 ½ years of age, thereafter, body weight did not show any significant changes. Body weight was stabilized between 2-3 years of age. From birth to 3 months age body weight enhanced by 164%, subsequently by 152% from 3 to 6 months age, then by 14 and 28% in next 3 months intervals, which warranted targeting better management during 6-12 months of age to achieve more body mass production. Seasons non-significantly (P>0.05) influenced growth rate (g/day), highest in summer (30.78±5.30) and lowest in rainy (24.15±2.10). Male kids had higher (P<0.01) growth rate (29.72±2.62) than females kids (24.73±2.95). Reproduction showed higher proportions of female birth (60.17%) as compared to male (39.83%). Goats had reproductive efficiency of 50.98% singles, 43.14% twins and 5.88% triplets under IMS. The in-house production environment of IMS was stressful being THI 86-90 in summer and rainy seasons, and 77-80 in winter seasons. The flooring hygiene (1-4 scale) of goat houses in IMS ranged from 3.18±0.08 to 3.72±0.06 in wooden to concrete floors. It was recommended that targeting for higher growth rates during 6-12 months of age and increase in proportions of multiple births might enhance productivity and profitability of Black Bengal goat farming under IMS.
... Çiftlik hayvanlarında aşırı sıcak ortamlarda termoregülatör mekanizmaayı etkileyen en baskın morfolojik özellikler vücut boyutu ve şeklidir ve sıcak ortamlarda vücut boyutu hayvanlarda su kaybını ve ısı kazancının ayarlanmasınada yardımcı olur (Silanikove, 2000b;Cain vd., 2006). Keçilerin sindirim özellikleri, sınırlı mera ile hayatta kalmalarını sağlamak için oldukça önemlidir. ...
... There are many differences between cows and goats, not only in body size, rumen size, and rumen content passage rate, but also in feeding behavior, feed intake, digestive function, nutrient utilization, water economy, turnover rate, and digestive efficiency [68][69][70]. Some of these differences are innate, while others result from their adaptation and interaction with various environmental factors. ...
The aim of this study was to compare the diversity and composition of fecal bacteria in goats and cows offered the same diet and to evaluate the influence of animal species on the gut microbiome. A total of 17 female goats (Blond Adamellan) and 16 female cows (Brown Swiss) kept on an organic farm were fed pasture and hay. Bacterial structure in feces was examined by high-throughput sequencing using the V4–V5 region of the 16S rRNA gene. The Alpha diversity measurements of the bacterial community showed no statistical differences in species richness and diversity between the two groups of ruminants. However, the Pielou evenness index revealed a significant difference and showed higher species evenness in cows compared to goats. Beta diversity measurements showed statistical dissimilarities and significant clustering of bacterial composition between goats and cows. Firmicutes were the dominant phylum in both goats and cows, followed by Bacteroidetes, Proteobacteria, and Spirochaetes. Linear discriminant analysis with effect size (LEfSe) showed a total of 36 significantly different taxa between goats and cows. Notably, the relative abundance of Ruminococcaceae UCG-005, Christensenellaceae R-7 group, Ruminococcaceae UCG-010, Ruminococcaceae UCG-009, Ruminococcaceae UCG-013, Ruminococcaceae UCG-014, Ruminococcus 1, Ruminococcaceae UCG-002, Lachnospiraceae NK4A136 group, Treponema 2, Lachnospiraceae AC2044 group, and Bacillus was higher in goats compared to cows. In contrast, the relative abundance of Turicibacter, Solibacillus, Alloprevotella, Prevotellaceae UCG-001, Negativibacillus, Lachnospiraceae UCG-006, and Eubacterium hallii group was higher in cows compared with goats. Our results suggest that diet shapes the bacterial community in feces, but the host species has a significant impact on community structure, as reflected primarily in the relative abundance of certain taxa.
... Their sustenance mainly depend upon grazing. They are able to browse on plants that would not normally useful for other animals [3,4]. ...
... Therefore, the skin is surrounded by air to which most body heat is transferred by convection, reducing the conductive heat loss [82]. In addition, the animals transfer only a small part of their heat load through their feet to the ground because of the small area of contact [83]. Sprinklers from the floor or above the cattle, showers as cattle exit the milking parlour and overhead fans can be used on some farms to mitigate heat stress, which facilitates heat load reduction and increases lying down time [84]. ...
Egypt already has conditions in summer that cause heat stress for livestock, and predicted climate changes suggest that these will be exacerbated over the course of this century. As well, extreme climatic events make the mitigation of climate change difficult but important to understand. Apart from neonates, farm animals have upper critical temperatures in the region of 25–30 °C, whereas temperatures in summer regularly exceed 40 °C for prolonged periods. The temperature and humidity data were collected half hourly to calculate Temperature Humidity Indices and demonstrate that Egyptian livestock at two centers of livestock production in the country would experience heat stress in summer for extended periods of each day. The impact of rising temperatures on livestock in Egypt was reviewed, where extensive resources to mitigate the impact are not often available. It was found that, although there are some prospects to mitigate some heat stress, by using agroforestry systems of production for example, these are unlikely to have a major impact, and reduced food security may ensue over the course of this century.
... Livestock farming, particularly grazing goats, constitutes the prevalent agricultural activity in the mountainous areas of the southern Mediterranean Basin. Due to their high adaptability to harsh environments, goats do not need to receive any significant investments [4][5][6]. In addition, they contribute to the livelihoods of poor herders and provide several benefits to mountainous populations [3,7]. ...
The recent development of advanced electronic sensors to monitor and record animal grazing activity provides a real opportunity to facilitate understanding of their behavioral responses. This study aimed to characterize the grazing activity and protein–energy requirements of grazing dairy goats in a Mediterranean woodland in northern Morocco by combining two sensors, the Global Positioning System (GPS) and three axis accelerometers. An experiment was conducted in a representative woodland with eight dairy goats. Measurements were undertaken during the three main grazing seasons (spring, summer, and autumn) for two consecutive and contrasting years. Grazing activity parameters were assessed using GPS collars and leg position sensors. The results showed that grazing time was higher in spring (57% and 59%) than in summer (39% and 36%) and autumn (41% and 45%), respectively, for the dry and wet years (p < 0.001). During the two studied years, the daily horizontal distance traveled by the goats increased from spring (about 4.5 km) to summer (about 6.5 km) and autumn (about 7.4 km), while greater daily vertical distances were recorded over similar distances during summer–autumn. Several protein–energy intakes that were insufficient to cover the requirements of the grazing goats were recorded, especially in summer. The combination of GPS collars and accelerometers contributed to a better understanding of the grazing activities of dairy goats in the studied Mediterranean woodland. These findings provide useful data on the protein–energy balances of dairy goats and offer additional information that could be useful for herders and managers to enhance goat-feeding strategies and guarantee high-performance in the semi-extensive traditional goat farming system.
Background and Objective: Knowledge of genetic variations in heat tolerance and immunocompetence
The recurring drought and limited rainfall patterns occasioned primarily by climate change in sub-Saharan African countries threaten sustainable animal agriculture. The irreversibility of this natural phenomenon calls for an intensive and urgent selection of adaptable breeds that can cope but with minimal compromise on production indices. A water scarcity simulation study was conducted to assess the adaptation potential of Nguni goats to regulated watering by evaluating their growth performance, tolerance to heat and water stress and blood indices during the dry summer months. Eighteen growing Nguni goats (average age: 1 year; BW: 19.25 ± 1.6 kg) were assigned equally to three treatments: W0, without water restriction (WR); W70, WR of 70% ad libitum water intake (WI); and W50, WR of 50% ad libitum WI. The experimental trial lasted for 75 d following a 14-day acclimatisation to the housing condition. Data on growth performance, body thermal gradient, skin temperature (ST) and rectal temperatures, respiratory rate (RR), body condition scores (BCs), linear body indices and blood biochemical indices were taken. The results showed that the final BW was not affected (P > 0.05) by the water restriction levels. The daily gain, DM intake and total BW gain were similar (P > 0.05) in groups W70 and W50. Body thermal gradient and ST were not affected (P > 0.05). The RR and BCs decreased (P 0.05) for groups W70 and W50. There is an haemocentration (W0
Los taninos son compuestos fenólicos secundarios de elevado peso molecular presentes en la naturaleza. Se encuentran frecuentemente en frutas, árboles, especies forrajeras templadas y otras especies como sorgo y maíz utilizadas comúnmente en la alimentación del ganado. Recientemente se ha encontrado que la adición de los taninos a dietas de rumiantes favorece la baja fermentación ruminal de la proteína en la dieta, lo que mejoraría el comportamiento productivo en rumiantes. Así, el objetivo de este estudio fue determinar el efecto de la adición de taninos en la dieta de corderos en engorda para evaluar el comportamiento productivo. Se utilizaron 32 corderos, 16 machos y 16 hembras con un peso promedio inicial de 23 ± 0.167 kg y 20 ± 0.188 kg, respectivamente. Las unidades experimentales fueron asignadas a uno de los siguientes tratamientos: dieta basal machos (MT1), dieta basal hembras (HT1), dieta basal más 4 g de taninos/kg de alimento machos (MT2) y dieta basal más 4 g de taninos/kg de alimento hembras (HT2). Para el diseño del experimento se bloqueó por sexo y peso vivo para luego ser asignados al azar a uno de los grupos. Para el total de la prueba solo en los machos se observó que la ausencia de taninos en la dieta incrementó el consumo de materia seca ((P<0.05; CMS) y la ganancia diaria de peso (GDP); en cuanto a la eficiencia alimenticia (EA) no hubo diferencias entre tratamientos. En general, la presencia de los taninos incidió negativamente en machos pero no en hembras. DOI: https://doi.org/10.54167/tch.v11i1.164
The present study was carried out to study the morphology of the goat's soft palate and palatine tonsil by gross anatomy, morphometry, light and scanning electron microscopy (SEM). Twelve heads of normal adult (18–24 months) apparently healthy goats of both sexes were collected from local commercial slaughterhouses in Qena Governorate, Egypt. The oral cavity was dissected, and samples were collected for both light and SEM. The soft palate of the goat formed the caudal continuation of the hard palate. It was relatively short, it extended from the level of the caudal border of the last upper molar tooth to terminate caudally against the base of the epiglottis. The oral mucous membrane of the soft palate was covered by non‐keratinized stratified squamous epithelium. The lamina propria and submucosa contained connective tissue fibers, diffuse and nodular lymphatic tissue, striated muscle fibers, and a large number of mucous and serous palatine glands. By SEM, the ventral surface had several rounded openings occupied by flower‐like structures. These openings represented the entrances to the palatine glands. The palatine tonsil was large and protruded from a fossa in the lateral wall of the oropharynx. It had 2–3 elongated irregular openings that lead to the underlying crypts. These crypts were well‐developed and lined by non‐keratinized stratified squamous epithelium. The epithelium of the tonsillar crypts directly covered lymphoid tissue and was infiltrated by lymphocytes. Tonsillar glands of pure mucous type were demonstrated. In conclusion, the study provides the basic morphological features of soft palate, as well as the palatine tonsil of the goat by gross observation, light and SEM. The palatine tonsils of goat were well‐developed with extensive crypt system, suggesting their essential role in the immunological response against antigens that enter through the oral cavity. The current findings may be useful to understand the role of the palatine tonsil in immunity and disease pathogenesis.
Research Highlights
The study reported the basic morphological features of soft palate and palatine tonsil of goat.
The ventral surface of the soft palate had several rounded openings occupied by flower‐like structures.
The palatine tonsils of goat were well‐developed with extensive crypt system.
The findings might help to understand the role of the palatine tonsil in immunity and disease pathogenesis.
Various direct and indirect environmental constraints have an impact on livestock performance. The physiological parameters, such as rectal temperature, heart rate, and respiratory rate, are the primary indicators of thermal stress. Under a stressed environment temperature humidity index (THI) had established as a vital measurement to identify the thermal stress in livestock. THI in association with climatic variations can define the environmental effect as stressful or comfortable for livestock. Goats are small ruminants that adapt to a wide range of ecological variations due to their anatomical and physiological characteristics. However, the productivity of animals declines at the individual level during thermal stress. Stress tolerance can be determined through genetic studies associated with at the cellular level using physiological as well as molecular approaches. Information on genetic association with thermal stress in goats is scanty, this severely affects their survival and hence productivity of livestock. The ever-increasing demand for food across the globe needs deciphering novel molecular markers as well as stress indicators that play a vital role in livestock improvement. This review represents an analysis of current knowledge of phenotypic differences during thermal stress and signifies the importance of physiological responses and their association at the cellular level in goats. The regulation of vital genes associated with thermal stress such as Aquaporins (AQP 0, 1, 2, 4, 5, 6, 8), aquaglyceroporins (AQP3, 7, 9, and 10) and super-aquaporins (AQP 11, 12); BAX inhibitors such as PERK (PKR like ER kinase), IRE 1(inositol-requiring-1); Redox regulating genes such as NOX; Transport of Na+ and K+ such as ATPase (ATP1A1) and several heat shock proteins have been implicated in heat-stress related adaptations have been elucidated. As these changes have a significant impact on production performance as well as on livestock productivity. Such efforts may help in the development of molecular markers and will assist the breeders to develop heat-tolerant goats with improved productivity.
Infections of the gastrointestinal tract with nematodes remains one of the main pathological constraints associated with outdoor breeding of goats both in temperate and tropical areas. The usual mode of control of these parasitic infections is based on the repeated use of chemical anthelmintics, but the prevalence and diffusion of anthelmintic resistances in nematode populations is particularly high in goats, and the sustainability of the system is now questioned. Therefore, there is a deep interest to seek and explore alternative solutions to chemotherapy. Among those, tannins and tanniferous plants represent one of the most promising options. However, information on the effects of these polyphenolic compounds on nematode infection in goats is far less abundant than in sheep. This review presents data obtained from both outdoor and indoor studies aiming at examining the relationship between the consumption of tannins or tanniferous plants, particularly those composing the vegetation of rangeland and the resistance and resilience of goats to trichostrongyle infections. Results from in vitro studies with extracts from different plants which are grazed or browsed by goats are also discussed in relation with the possible mechanisms of action of tannin in goats. These results are compared to those acquired in sheep and are discussed in relation with the physiological adaptation of goats to tannin consumption. Further research perspectives and possible applications for the control of nematode infections in goats are also briefly evoked.
The aim of this chapter is to discuss possible perspectives on breeding and genomics to improve goat productivity in Southern Africa. Goats play a major role in poverty reduction, rural economy and improved nutrition. Indigenous goats possess vast genetic diversity suitable for continual genetic improvement, changing environments and food security. Most of goat production in the region is, however, practised under low-input extensive management resulting in decreased population, reduced genetic variation and selection response, and ultimately low productivity. The goat industry is generally faced with numerous challenges such as improper genotype, feeding and marketing strategies. Application of molecular genomics has opened new horizons for animal improvement by accelerating genetic progress, accuracy of selection for superior traits as well as mapping genes of economic importance. Community-based breeding improvement programme will facilitate sustainable goat improvement and the goat value chain that include management of resources and services and collective decision-making. The genetic gain can be augmented through the integration of genomics by screening for potentially numerous specific mutations of interest or genomic variants that underlie important traits.
Understanding the genetic mechanism of how animals adapt to extreme conditions is fundamental to determine the relationship between molecular evolution and changing environments. Goat is one of the first domesticated species and has evolved rapidly to adapt to diverse environments, including harsh high-altitude conditions with low temperature and poor oxygen supply but strong ultraviolet radiation. Here, we analyzed 331 genomes of domestic goats and wild caprid species living at varying altitudes (high > 3000 m above sea level and low < 1200 m), along with a reference-guided chromosome-scale assembly (contig-N50: 90.4 Mb) of a female Tibetan goat genome based on PacBio HiFi long reads, to dissect the genetic determinants underlying their adaptation to harsh conditions on the Qinghai-Tibetan Plateau (QTP). Population genomic analyses combined with genome-wide association studies (GWAS) revealed a genomic region harboring the 3'-phosphoadenosine 5'-phosphosulfate synthase 2 (PAPSS2) gene showing strong association with high-altitude adaptability (PGWAS = 3.62 × 10−25) in Tibetan goats. Transcriptomic data from 13 tissues revealed that PAPSS2 was implicated in hypoxia-related pathways in Tibetan goats. We further verified potential functional role of PAPSS2 in response to hypoxia in PAPSS2-deficient cells. Introgression analyses suggested that the PAPSS2 haplotype conferring the high-altitude adaptability in Tibetan goats originated from a recent hybridization between goats and a wild caprid species, the markhor (C. falconeri). In conclusion, our results uncover a hitherto unknown contribution of PAPSS2 to high-altitude adaptability in Tibetan goats on QTP, following interspecific introgression and natural selection.
Understanding the genetic mechanism of how animals adapt to extreme conditions is fundamental to determine the relationship between molecular evolution and changing environments. Goat is one of the first domesticated species and has evolved rapidly to adapt to diverse environments, including harsh high-altitude conditions with low temperature and poor oxygen supply but strong ultraviolet radiation. Here, we analyzed 331 genomes of domestic goats and wild caprid species living at varying altitudes (high > 3000 m above sea level and low < 1200 m), along with a reference-guided chromosome-scale assembly (contig-N50: 90.4 Mb) of a female Tibetan goat genome based on PacBio HiFi long reads, to dissect the genetic determinants underlying their adaptation to harsh conditions on the Qinghai-Tibetan Plateau (QTP). Population genomic analyses combined with genome-wide association studies (GWAS) revealed a genomic region harboring the 3'-phosphoadenosine 5'-phosphosulfate synthase 2 (PAPSS2) gene showing strong association with high-altitude adaptability (P GWAS = 3.62 × 10-25) in Tibetan goats. Transcriptomic data from 13 tissues revealed that PAPSS2 was implicated in hypoxia-related pathways in Tibetan goats. We further verified potential functional role of PAPSS2 in response to hypoxia in PAPSS2-deficient cells. Introgression analyses suggested that the PAPSS2 haplotype conferring the high-altitude adaptability in Tibetan goats originated from a recent hybridization between goats and a wild caprid species, the markhor (C. falconeri). In conclusion, our results uncover a hitherto unknown contribution of PAPSS2 to high-altitude adaptability in Tibetan goats on QTP, following interspecific introgression and natural selection.
Undernourishment and food insecurity are still challenges threatening poor urban and rural communities. Approximately 12% of the global population faced severe food insecurity in 2020, representing 928 million people. A significant fraction of the world’s land surface is covered by drylands, and this proportion is expected to increase in the future, affecting the food security and livelihood of 2 billion people due to climate change. Goats have traditionally been a significant asset and source of protein for rural communities inhabiting arid and semiarid regions of the world. We hypothesize that goats were intentionally selected by communities in dry environments and might be the optimal animal to breed in the future due to their capability to survive in dry environments and to utilize less water than other livestock production systems. However, it must be considered that only a small fraction (1%–2%) of the total water consumed by goats is drunk or utilized directly by the animals. Most of the water consumed is utilized to grow the feed that livestock such as goats consumes. Which in most regions of the world is green water due to goats feed on the vegetation that grows in rainfed rangelands. Increasing water efficiency in goat production is thus critical in the context of increasing water scarcity and desertification. However, there is little research on goat water productivity and the impact of decreasing water security on the sustainability of goat production and, hence, on the livelihoods in small communities in developing countries. Therefore, the impact of increasing water scarcity and desertification on goat production in rainfed lands should be a research priority.
Goat milk is considered an ideal food due to its nutritious and medicinal values. This study aimed to evaluate the physico-chemical and microbial qualities of Black Bengal goat (BBG) milk. The study includes 120 BBG reared in six different goat farms in the Sylhet region of Bangladesh. A total of 120 different milk samples were collected. The laboratory examination was conducted at the Dairy Science Laboratory of Sylhet Agricultural University, Bangladesh, from January through February 2021. Milk samples that passed the organoleptic test and C.O.B. test mainly were (83.3 %) normal. The collected samples' physical parameters (color, flavor, and taste) were almost similar. Chemical composition of the analyzed raw milk sample was an average fat of 5.5±0.44%, protein 3.45 ± 0.13%, lactose 5.23 ± 0.24%, solids not fat (SNF) 8.23 ± 0.27%, and salt 0.78 ± 0.02%. Chemical composition of the analyzed milk from different farms was similar, whereas Total plate count (TPC) and the coliform count showed significant variation among farms. The farm-2 had a low microbial load due to good hygienic and sanitary practices followed in milking and milk transportation. The order of parity and lactation stage played a major role in influencing the fat percentage of BBG milk. Fat content increased with later parities and at the end of lactation. Protein and solids not fat (SNF) content were significantly (P<0.05) affected by parity order, whereas advancing the stage of lactation increased the protein, solids not fat (SNF), and decreasing the salt content. TPC and coliform count were not significantly affected by parity and lactation stage.
The results of studying the adaptive abilities of young sheep depending on their origin and their relationship with productivity are presented. Temperature, velocity and humidity at birth of lambs (April) were 4.7 °C, 4.2 m/s and 17.7%, at the age of 6 months (October) - 1.0 °C below zero, 4.9 m/s and 33.7% respectively. The best indicators of live weight up to 6 months of age are shown by medium-wool young Aginskaya breed. Young rams at the age of 6 months had an advantage over their fine-wool counterparts of Transbaikal breed by 3.7% in terms of average live weight, and the gimmers by 6.3% (p > 0.05). The rams of the Transbaikal breed had the best height measurements of the body by 0.4 cm at the withers and by 1.3 cm in the height at hips. The Aginskaya breed peers were distinguished by better volume and latitude measurements, including oblique torso length and chest depth. The Aginskaya breed has longer ears (23,2-23,8%), neck (9,7-17,5%) and head (1,2- 2,5%), narrower forehead (11,5-17,6%) and less voluminous neck (5,1-7,2%) than their fine-wool counterparts. Clinical and hematological parameters were within the physiological norm. The lowest body temperature on the skin surface of the experimental youngsters at birth and at 6 months of age was noted in the ear area (25.2-26.0 °С), the highest - on the central part of the abdomen (29.3- 33.4 °С). In terms of skin thickness, depending on the origin of the sheep, the greatest difference was noted in the SCP, MR-12, and SCP areas. In fine-wool individuals, it is 28.0-39.1% thicker in the SCP, 9.7-46.2% thicker in the MR-12, and 25.0-43.5% thicker in the SCP. In test specimens a positive correlation of live weight with the height at hips (0.591-0.906), with the girth of the metacarpel (0.133-0.240), and with the width of the forehead (0.173-0.590) was detected. There was a correlation between live weight and head and neck length in medium-wool breed individuals (0.060- 0.463 and 0.147-0.394), as well as a weak correlation with skin thickness on MR-12. In fine-wool counterparts, there is a medium correlation between live weight and neck girth (0.490-0.553) and skin thickness in the SCP area (0.469-0.755).
Methionine is an essential amino acid that contributes to protein formation, fetal development, and milk synthesis. Thus, we hypothesized that a supplementation with Optimethione® during the last third of gestation in female goats will increase the maternal body live weight, the milk yield and milk composition and the offspring weight and body mass index at birth and postnatal performance. We fed (n = 30) or not (n = 30) herbal methionine Optimethione® to pregnant mul-tiparous Alpine goats from gestational day 100 until delivery. We evaluated the productive var-iables from the dams and offspring. Maternal intake of herbal methionine Optimethione® dur-ing pregnancy did not increase the live weight or increase the milk yield and composition. However, the tested offspring variables were influenced by the maternal intake of herbal me-thionine Optimethione® during gestation by improving the birth weight, body mass index, and postnatal growth pattern. An increase in birth weight would be expected to increase neonatal survival up to weaning. Moreover, a relative fatness is required for reproductive success; thus, offspring that are born heavier and bigger can display a faster postnatal growth and accelerate the onset of puberty and increase reproductive success.
As the expectation of the influence of climate change scenarios increases, the effect of heat stress on small ruminants is significant due to their importance for smallholders in stressful environments. This article reviews the physical, physiological, metabolic, genes (N=126) and genetic pathways that affect heat stress response in sheep and goats. Molecular functions (N=304) linked to cytokine, growth factor, hormone and ATPase activity, as well as binding proteins, ATP, DNA, metal ions were prevalent in these analyses. As for biological processes (N=1803), gene expression and regulation, cell differentiation, apoptotic processes, cytokine pathways and inflammatory responses are important. Biological processes were centred on regulation, positive/negative, cell, signals, processes, proteins and pathways, while molecular functions included binding, DNA/RNA, protein, factors and activity. This review will contribute to have a better understanding of the complex animal´s response to heat stress and it should support scientific groups to delineate new studies as well to stimulate the generation of more data towards the development of strategies and methods to reach more sustainable animal production systems.
A one-year study was initiated in August, 1975, to examine the nutritive content in diets of four kinds of sympatric ruminants on excellent condition rangeland of the Edwards Plateau in Texas. Sheep, Angora goat, and Spanish goat diets were collected from animals fitted with permanent esophageal cannulae. Nutritive content of white-tailed deer diets was estimated by hand-plucking representative forages as the deer were observed grazing them. Mean, annual levels of crude protein (CP) were similar among the four kinds of animals. All diets were lowest in CP during January and February, with livestock diets showing higher levels than deer. However, deer diets were higher in CP than sheep and goat diets during spring and summer. During January and February, the livestock diets warranted only minimum protein supplementation while deer diets were significantly below recommended levels. Digestible energy (DE) levels were higher for sheep diets than for diets of either goats or deer. Similarly, the goat diets were higher in DE than deer diets. The DE levels were generally adequate for sheep but critically low for Angora goats during late gestation. Deer diets were very low in DE during winter and again in early summer, coinciding with the period of peak lactation. Energy would appear to be more limiting for animal production than protein under the conditions of this research.
A positive correlation of weight with latitude in homoiotherms (Bergmann's rule) cannot normally depend upon the physics of heat exchange. Most latitudinally widespread mammals in North America do not follow this rule. Those that do are usually carnivores or granivores; a change in their body size reflects a change in the size of their prey. A latitudinal change in the size of available prey is due either to the distribution of the prey species or to the distribution of other predators utilizing the same prey species. Only the smallest species of a set of similar predators normally will conform to Bergmanns rule, and then only beyond the limits of distribution of the largest species. These changes in size seem to be another example of character displacement.
Studies in the past 20 years have often interpreted size fluctuations in fossil mammal remains as a response to climatic change, in accord with Bergmann's rule. However, such paleoecological inference requires careful consideration of changes in community composition that could cause ecological character displacement or release. Recent size gradients of mammals should be screened for the possibility of character displacement if fossil size gradients are to be used as a "paleothermometer' for past climate. The use of teeth in paleontological studies as a measure of body size presents a further complication; for several carnivore guilds, it appears that competitive pressures act most strongly on tooth size. -from Authors
The diets selected by esophageal-fistulated indigenous goats grazing on desert grassland in northern Mexico were characterized throughout the year, in terms of botanical composition, nutrient content and preference indices. Browse (primarily Parthenium incanun, Agave lechuguilla, Buddleja scordioides, and Atriplex canescens), constituted over 80% of the goats' diet throughout the year except 57% during the rainy season in April. Grasses made up less than 10% of the diet for most of the year except during the dry period in October. Bouteloua karwinskii was the grass most utilized. Sphaeralcea angustifolia was the most important forb in goats diet (23% of the diet in April). Goats showed the highest preference for A. canescens, B. scordioides, and S. angustifolia. Nutritional adequacy of forage for the greater part of the year was poor. Goats were not able to attain the NRC recommended total consumption of protein for pregnancy and lactation (levels of protein ranged from 7.1 to 12.1%). Phosphorus and energy intake were estimated to be inadequate always, even for maintenance. Despite these constraints, goats productivity in the area is acceptable. Perhaps indigenous goats have lower nutrient requirements than those given by NRC.
The FAO projected demand for milk for the year 2000 in the developing tropical world is estimated to be 242 million tons whereas the projected supply is estimated to be 177.6 million tons. In the ‘developing’ tropics where there are about 95% of the total goat population, this increased demand could be best made up from goat milk. Although there is the potential for improved milk production in the tropics from the dairy goat, information on breeds and breed societies for goats and, in particular, tropical dairy goats is lacking, and therefore represents an important area which needs to be addressed. This review covered dairy goats in the tropics; global goats' milk production; the characteristics of the dairy goat in the tropics (feeding behaviour, digestive efficiency, reproductive efficiency); milk production and the efficiency of milk production by goats in the tropics (temperate breeds in the tropics, tropical and sub-tropical breeds, efficiency of milk production in dairy goats); dairy goat adaptation to the tropics (physiological and anatomical, feeding behaviour, socio-economical and general). The conclusions were that the goat is well adapted to the tropics; has short generation intervals, high fertility, prolificacy and fecundity; high heritability for milk production (0.5); superior digestive efficiency over dairy cattle when fed low quality forages (kg milk yield100 kg DOM of 67.1 to 145; 86 to 101.5; 73.6 and 71.1 to 91.1 for goats, dairy cattle, dairy buffalo and sheep respectively); are more efficient milk producers under tropical conditions (kg milk yieldkg live weight of 2.8 to 7.1, 2.4 to 3.4, and 4.0 for goats, dairy cattle and dairy buffalo, respectively); goats' milk owing to its composition has a potentially greater role to play in future human nutrition and medicine than milk from cattle; and farmers would more readily setup or expand goat enterprises because of the lower capital investments required concurrent with lower risks.
Tannins and other phenolics interfere with the interpretation of results from the detergent system of forage analysis. Leaves and apices from browse can contain up to 50% of their organic matter as phenolics including tannins that are soluble in aqueous acetone. Leaves and apices from browse that contain soluble proanthocyanidins (condensed tannins) also contain proanthocyanidins that are insoluble in both aqueous acetone and neutral-detergent. The content of insoluble proanthocyanidins is positively correlated with neutral-detergent fiber (NDF) and fiber-bound nitrogen. Condensed tannins may bind protein and make it less soluble in neutral-detergent and increase the content of NDF. The behavior of phenolics and tannins in the detergent system of forage analysis is discussed in relationship to estimating the nutritive value of 17 East African browse species.
Techniques of statistical analysis are utilized to begin to unravel the causes involved in the evolution of body size clines in mammalian carnivores. Variables included are productivity, temperature, latitude, competitive pressure and size of potential prey. Temperature and latitude are shown to be good predictors of body size in several species. Indeed, they seem to be measures of the same cause, as has long been maintained by those attempting to explain Bergmann's rule. But temperature does no better than latitude at predicting size. Thus temperature is probably not a direct cause of Bergmann's rule in these animals. The measure of total primary productivity used (actual annual evapotranspiration, AE) proved to be one of the better correlates, especially at lower productivities. Apparently relatively meager food supplies set upper limits to body size. Except in a very few cases, the biotic variables of competitive pressure and prey size were only second-rate predictors. Discussion of the patterns that have been shown by this analysis is included.
The combined effect of infrequent drinking and poor feed quality on water economy and energy metabolism was investigated in Bedouin goats indigenous to the extreme deserts of the Middle East. Goats maintained under midsummer conditions were watered either once every 4 d, or once daily. Under each of the drinking regimes, they were tested on three diets: high-quality roughage (alfalfa hay), feed of medium quality (dry Rhodes grass) and low-quality feed (wheat straw). Goats maintained constant body mass in all trials except when maintained on wheat straw and watered once a day. Infrequent drinking as well as feed of low quality each independently reduced water requirement of the goats. When on alfalfa hay, goats watered once daily consumed an average (@+ 1 SD) of 248 @+ 21 mL@?kg^-^0^.^7^5@?d^-^1. The combined effect of infrequent drinking and a diet of wheat straw resulted in a water consumption of only 93 @+ 10 mL@?kg^-^0^.^7^5@?d^-^1. Gross energy (GE) intake on high-quality roughage was higher than on low-quality feeds. Infrequent drinking hampered feed intake more markedly on the high-quality feed than on the low-quality ones. On alfalfa hay, daily GE intake of goats watered daily amounted to 1496 @+ 43 kJ@?kg^-^0^.^7^5@?d^-^1 and to only 901 @+ 26 kJ@?kg^-^0^.^7^5@?d^-^1 in those watered once every 4 d. On Rhodes grass a GE intake of 828 @+ 70 kJ@?kg^-^0^.^7^5@?d^-^1 vs. 699 @+ 58 kJ@?kg^-^0^.^7^5@?d^-^1 was measured, and on wheat straw the GE intake for the two regimes was: 532 @+ 72 kJ@?kg^-^0^.^7^5@?d^-^1 vs. 416 @+ 57 kJ@?kg^-^0^.^7^5@?d^-^1. Digestibility of the high-quality feed was higher than that of the low-quality one. When the goats were watered infrequently digestibility increased to a greater extent on low-quality feeds than on alfalfa hay. Infrequent drinking and low-quality feed, each independently, resulted in a decrease in the resting metabolic rate of the goats. When the goat was watered once daily and fed alfalfa hay, its O"2 consumption was 724 @+ 14 mL@?kg^-^0^.^7^5@?h^-^1. O"2 consumption rate was only 54% of this when the goats were fed on wheat straw and watered once every 4 d. We conclude that infrequent drinking increases feed digestibility and reduces the animal's demands for metabolizable energy, and may thus help Bedouin goats balance their energy metabolism when nutritional conditions in the desert deteriorate.
-The digestive secretions of both old world and new world camels are considered The salivary glands closely resemble those of cattle and sheep both morphologically andphysiologically. Evidently, as in the Ruminantia, they provide almost all of the fluid and alkali needed to maintain favourable conditions for microbial digestion in the forestomach. The glandular epithelium of the camees forestomach does not seem to have an important role in this respect except in that its free permeability to volatile fatty acids allows exchange of fatty acids for bicarbonate, as occurs also across the squamous keratinised epithelium of the Ruminantia. Little is known of t?te secretions and digestive processes of the hindstomach and iktestines. A large part (up to about 90%) of the urea formed in the camees body may be hydrolysed in the gut. This provides and endogenous source of nitrogen for microbial protein synthesis. The forestomach contains about a quarter of the water in the whole body It serves as a substantial and dynamic reservoir, releasing water during dehydration and accommodating it when a thirsty animal takes a huge drink to allow gradual rehydration of the tissues. Key words: Dromedary, secretion digestive. RESUME -<<La sécrétion digestive chez les chameaux,,. Les sécrétions digestives des chameux du vieux monde et du nouveau monde sont étudiées. Les glandes salivaires ressemblent de près de façon morphologique et physiologique à celles des bovins et des moutons. Evidemment, comme pour les Ruminants, elles produisent presque tout le fluide et toutes les bases nécessaires pour maintenir des conditions favorables pour la digestion microbienne pour les préestomacs. L'épithelium glandulaire du préestomac du chameau ne semble pas avoir un rôle important dans ce contexte, à part sa perméabilité aux acides gras volatiles permettant l'échange de bicarbonate à la place d'acides gras comme cela se produit à travers l'épithelium squameux kératinisé des Ruminants. Les sécrétions et les actions digestives des postestomacs et de l'intestion sont peu connues. Une grande partie (jusqu'à environ 90%) de l'urée formée dans le corps du chameau peut être hydrolysée dans son tube digestif. Ceci produit une source endogène d'azote pour la synthèse des protéines microbiennes. Les préestomacs contiennent environ un quart de l'eau du corps entier. Ils remplissent le rôle de réservoirs importants et dynamiques, relâchant l'eau pendant la déshydratation et l'accumulant lorsqu'un animal assoiffé s'abreuve rapidement, permettant de cette façon une réhydratation graduelle des tissus. Mots-clés: Dromadaire, secretion digestive.
Comparative aspects of digestive physiology and nutrition in goats and sheep are discussed in the context of differences due to feeding behaviour, intake, digestive function, utilisation of nutrients, water economy and turnover rate, and digestive efficiency. Some of these differences are inherent, but others result from adaptation and interaction with various environmental factors. Present evidence suggests that goats are more selective, have a higher intake, rumen volume and gut fill, salivary secretion and rumen ammonia, urea recycling but lower water intake and turnover rate compared to sheep. Increased salivary function and urea recycling may be associated with their ability to have a higher tolerance for tannins. Concerning digestive efficiency, the available evidence suggests that with good quality forages with organic matter digestibility values of about 60% and above, there appear to be no differences between-species. With poorer quality forages and roughages on the other hand, goats appear to digest fibre more efficiently than sheep. Precise reasons for these and a much better understanding of the real differences merit more thorough investigations, but are associated with particle size, salivary secretion, microbial activity, rate of digestion, partition of nutrients, water intake and turnover. These investigations are urgent and justified by the fact that both species are very valuable resources in the developing countries. The implications of the findings relate to factors that govern the choice of species and more complete use of potentially important breeds of goats and sheep, the available feed resources, application of more appropriate feeding strategies, and increased productivity from both species in the future.
The ways in which herbivores regulate their energy and water balance under hot, dry conditions are briefly reviewed. Cattle account for about two-thirds of the biomass of domestic stock in Africa, but their Eurasian origin means that their physiology and grazing behaviour are not wholly adapted to the natural pastures and climate of Africa, especially when drought strikes. In general, most herbivores can withstand heat and water shortage quite well, provided conditions do not become extreme. However, malnutrition will inevitably develop as pasture productivity declines under drought and overgrazing. This will affect most seriously animals that cannot range far from water and that depend mainly on drought susceptible grasses rather than on more resistant shrubs and trees.
Research was reviewed on structural characteristics of digestive systems, feeding, nutrition, body characteristics, lactation, milk composition, growth, production, reproduction, management systems, and farm economics of goats in the Near and Middle East. Damascus goats are the largest in the area; Kil goats, native to Turkey, are with 16 million the most numerous although least productive in milk and meat. Angoras are raised for mohair. Birth weights, growth rates, kidding rates, and milk yields are most in Damascus goats, followed by Malta and Kilis goats, with Kil and Angora goats last. Different milk nursing, kid and doe feeding systems are discussed. Urea can substitute successfully for part of the protein in rations. Kid carcasses are leaner and tastier than similar lamb carcasses. Carob pods and distillers dried grains can be used successfully in goat rations in relatively large proportions. Single-purpose goats made more money than dual purpose goats, and larger goat farms (200 goats) were more profitable than smaller units (80 goats). Practical research data, written in native languages, are hidden in little accessible annual reports in Turkey, Cyprus, and others.
The goat, from a world wide view, is both hated and treasured because it survives and remains productive in areas that are seriously overgrazed and eroded. Goats are probably not the initial cause of rangeland deterioration, but they may be the primary culprit during the latter stages of destruction. Goats are presented as being different in diet selection and gastrointestinal physiology from other domestic animals (cattle and sheep) and similar to deer. These differences offer explanations of why the goat's elevated requirements can be satisfied under environmental conditions unsatisfactory for other animals. Some experimental evidence indicates that the goat has greater digestive capacity; however, this advantage is likely only in certain breeds or strains having definable anatomical dimensions and is not a characteristic of the entire goat population. Experimental evidence suggests that the dairy goat does not hold a distinct advantage in efficiency of milk production over the highly developed dairy cow; however, it is likely that under many circumstances in the world, milk can be produced more efficiently from goats than from cattle due to resources available and adaptability of the animals.
The dried leaves of four species of shrub (Atriplex vesicaria, A. nummularia, Maireana pyramidata and Bassia diacantha) and four species of tree (Acacia pendula, Casuarina cristata, Geijera parvifora and Heterodendrum oleifolium) that are common to western New South Wales were fed to either sheep or goats to determine their digestibility. Four species were of low digestibility (< 50%) and one (C. cristata) had a digestibility of only 29%. Those of higher digestibility (A. nummularia 69%, M. pyramidata 58%, G. parviflora 59%) were only eaten sparingly: Digestibility alone gave a poor assessment of forage value because there was no correspondence between digestibility and organic matter intake. The intake of C. cristata (lowest digestibility) was much greater than that of A. nummularia or G. parviflora (highest digestibilities). There was good agreement (within 1 or 2 digestibility units) between in oitro (two-stage pepsin) and in vivo digestibility for six forages, but a greater disparity for M. pyramidata and H. oleifolium. For the trees the digestibility of cell wall constituents and acid-detergent fibre was low, in some cases less than 10%. This was not related to the amount of acid-detergent lignin in the fibre. Most samples were high in nitrogen (above 2%), which had a true digestibility ranging from 66 to 98%.
The distribution of water in the different body compartments of eight sheep of the Marwari breed was determined after imposing the following treatments: watering ad lib., restriction to 75%, 50%, and 25% respectively of normal daily water requirements (each treatment of 5 days' duration, with a 7-day normal drinking regime between treatments), and complete deprivation of water for 3 days. The total body water, the total blood and plasma volumes, and the extracellular, intracellular, and interstitial fluid volumes of the animals began to decrease when the water intake was reduced below 75% of the normal daily requirement. A reduction to 25% normal was similar in its effect to complete deprivation, at which the plasma volume fell by 43% and the extracellular fluid volume by 33%. The findings clearly point to an unusual ability of these animals to maintain circulation even when faced with considerable haemoconcentration.
Rumen Recycled Urea (RRU) was measured on dairy goats at different physiological stages: drying off, pregnancy (weeks 7, 15 and 20) and lactation (weeks 4, 8 and 20). In three experiments 45 measurements were obtained from animals fed diets varying in crude protein contents (10 and 14% of dry matter). Average RRU (6.58 g day−1) represented 15% of N intake but with high variations (σ = 5.73 g day−1, cv = 87%). Rumen Recycled Urea varied with physiological stage being higher for lactation and lower during drying period. For lactating goats, there was a significant correlation between RRU and milk protein yield. Food composition, nitrogen utilization, blood urea and rumen ammonia content explained 60% of RRU variation. There was an effect of physiological stage on RRU residues (measured RRU — estimated RRU): residues being higher at the end of pregnancy than during lactation or drying period. For the same nutritional status, rumen recycled urea is increased at the end of pregnancy and the beginning of lactation.
Sheep and goats exhibited different levels of tolerance to the effects of tannins extracted from oak leaves (Quercus ilex). Feed intake, N balance, and rumen ammonia concentrations decreased by 8%, 159% and 50%, respectively, in sheep infused intraruminally with tannins (P < 0.05). Similar measurements were not depressed (P > 0.05) in goats although mean rumen ammonia content was 39% less. In vivo DM digestibility was not significantly different for either sheep or goats. Averaged in vitro fermentation capacity was depressed 10% by tannin (8–12% concentration) in the rumen fluid from non-infused sheep given the same diet, but was improved by 9% for goats. Finally, tannin-infused goats lost in urine only 17% of the N ingested, while tannin-infused sheep excreted as much as 44%. The superiority of goats in dealing with tannin might result from the greater ability of their microbial population to degrade tannins, and/or their higher urea recycling and salivary secretion capabilities. Results derived from this study indicate that goats may be more suitable for grazing in oak woodland, especially during the season when alternative forage availability is scarce.
The digestion of the acid detergent fiber (ADF) fraction of vetch-oat hay was studied in two dromedaries and three sheep, all rumen-fistulated and fed vetch-oat hay with a concentrate. Dromedaries and sheep consumed similar amounts of feed dry matter (DM) per kilogram of metabolic weight, but dromedaries drank less water than sheep. There were no differences in the volatile fatty acid (VFA) and ammonia concentrations in the rumen between dromedaries and sheep, but pH was higher in the dromedaries than in the sheep (P < 0.05). The mixture of VFA contained more propionate and butyrate and less acetate in dromedaries than in sheep (P < 0.05). The protozoal concentration was higher in the rumen of sheep than of dromedaries. This result was consistent with the higher NNH3, concentration in sheep. Entodinium was the most abundant species in both dromedaries and sheep. Specific rates of rumen liquid (PEG) and particle (chromium-mordanted hay) outflow were higher and lower, respectively, in dromedaries than in sheep. Also, dromedaries had higher in sacco, in vitro, and fecal digestibilities of vetch-oat hay dry matter (DM) and ADF than sheep. In sacco, the potential degradable fraction was higher, but the rate of degradation was not. The greater utilization of ADF in the rumen by dromedaries is discussed in relation to the higher cellulolytic activity of the rumen microorganisms, the longer retention time of feed particles and/or the greater buffering capacity of the rumen contents of the dromedary against fermentation acids.
There is a high degree of concordance among the patterns of geographic size variation in birds in the eastern and central United States. This is demonstrated for 12 species by assuming that wing length measurements are an indicator of body size on the intraspecific level, and by arranging the data in the form of a grid of means of wing lengths for sample areas. Maps giving isophenetic lines for wing length indicate gradually increasing size clines northward and westward from Florida in the Hairy Woodpecker (Dendrocopos villosus), Dowy Woodpecker (Dendrocopos pubescens), Blue Jay (Cyanocitta cristata), Carolina Chickadee (Parus carolinensis), White-breasted Nuthatch (Sitta carolinensis), and Eastern Meadowlark (Sturnella Magna). In each case there is a trend for larger (or longer-winged) birds to extend southward in the Appalachian Mountains and for smaller (or shorter-winged) birds to extend northward in the Mississippi River valley. Maps made by a computer and automatic plotter using contour intervals of 0.5 mm of mean wing length for the Downy Woodpecker, for male White-breasted Nuthatches, and for female Blue Jays show that, in addition to the patter just mentioned, relatively longer-winged birds extend southward in the interior highlands of Arkansas, and relatively shorter-winged birds extend northward up other river valleys. These subtle relationships between intraspecific size variation and topographic features suggest that the link between the two phenomena may be precise adaptations to even minor climatic gradients. The relationship between these findings and the subspecies concept is discussed. Correlation coefficients for the patter of variation in the Downy Woodpecker with seasonal and annual wet-bulb temperature, vapor pressure, and absolute humidity were all either equal to or higher than correlations with dry-bulb temperature. Since these variables reflect the combined effects of temperature and humidity, the obvious indication is that size variation is more closely related to this combination than to temperature alone. Additional correlations using the mean wing length data for seven other species confirmed that wet-bulb temperature patterms are more closely related to bird size than either dry-bulb temperature patters or latitude. These relationship can be expressed numerically as regressions of mean wing length on either annual wet-bulb temperature or mean annual total heat per pound of air. Since increased evaporation at high altitudes and in arid areas accentuates the depression of a wet-bulb thermometer, my hypothesis may partially account for several cases of size variation in birds cited by others as disturbing exceptions to Bergmann's ecogeographic rule. Sections of a translation of Bergmann's paper published in 1847 are given. The biological mechanisms by which these relationships are maintainted are unknown, and the wide range of tolerance by birds to diurnal and seasonal temperature variations tends to mask them. If the well-established inverse relationship between weight and metabolic rate per gram of homeotherms is operative on the intraspecific level, the relationships can be discussed in terms of avenues of heat loss and of energy budget equations.
Small, black goats are found in arid and semi-arid regions of Morocco, but physiological adaptations that enable them to thrive in their harsh habitat have not been defined. Six goats (32+/-1 kg) were studied during lactation and nonlactation. Goats were kept indoors (ambient temperature 17-24 degrees C) and studied when fed twice daily, during 48 h of feed deprivation, and after refeeding. The goats were given 800 g concentrates. They ate 740+/-20 g (lactation) and 530+/-30 g/d (nonlactation; P<0.01), indicating that nonlactating goats voluntarily decreased their intake of concentrates. Wheat straw was available ad libitum and lactating goats consumed 230+/-60 g/d, while goats ate 340+/-50 g/d during nonlactation (P<0.05). Feed deprivation caused a 5% weight loss in both groups. Fed lao tating goats drank 1.5+/-0.2 l/d and nonlactating goats drank 1.0+/-0.1 l/d (P<0.05). Thus, the water/DM intake ratio was 1.7 in lactating and 1.3 in nonlactating goats. Water intake was unchanged during the first 24 h of feed deprivation, but then it dropped. Urine volume was not significantly reduced during feed deprivation. Plasma Na concentration decreased, while total plasma protein and haematocrit increased during deprivation, indicating that hyponatraemic hypovolaemia had developed. Plasma aldosterone increased during feed deprivation. Basal plasma glucose was elevated in lactating goats, but decreased during feed deprivation. Basal plasma insulin values were similar in both groups, and dropped during feed deprivation. Plasma urea was the same in both groups before feed deprivation and increased similarly during deprivation. Milk volume was 700+/-48 ml/d. It decreased by 30% the first and 57% the second day of feed deprivation. Two days after refeeding, milk volume was 384+/-81 ml/d. Total milk lactose secretion decreased during feed deprivation in proportion to decline in milk yield. Mean milk fat was 4.2 and 6.2% (at 08:00 and 16:00 h milking, respectively). It increased to 8 and 12%, respectively, during the second day of feed deprivation, and therefore milk fat secretion decreased only 18%. Milk solids content increased in proportion to fat. Milk Na was unchanged during feed deprivation, while milk K decreased. In conclusion, black Moroccan goats had a low water turnover and produced milk with high solids content. In response to acute feed deprivation, they developed hyponatraemic hypovolaemia with a drop in milk secretion like other goat breeds. However, Moroccan goats maintained water intake unchanged during the first stage of feed deprivation.
The presence of tannins in a large number of nutritionally important tree leaves hampers their utilization as ruminant feed. Generally, both the condensed and hydrolysable tannins are present in tree leaves, but some tree leaves may contain predominantly condensed tannins whereas others contain hydrolysable tannins. An inverse relationship has been found between the protein-precipitating capacity of tannins in tree leaves and their palatability, voluntary intake and digestibilities of crude protein and dry matter in grazing as well as browsing animals. Dietary tannins adversely affect rumen metabolism by bacteriostatic and bactericidal activities, and by inactivating several enzymes (e.g. carboxymethyl cellulase, proteases, glutamate dehydrogenase). The availability of sulphur and iron becomes limited to the animals consuming tannin-rich tree leaves.The prolonged consumption of tannin-rich leaves induces toxicity. Sheep ingesting 0.9 g hydrolysable tannins kg−1 body weight might show signs of toxicity in 15 days. Although animals like mule deer, rats and mice have been shown to secrete proline-rich proteins in saliva and these constitute the first line of defense against ingested tannin, the observed deleterious effects suggest the inadequacy of defence against a high quantity of dietary tannins.A tannin content of ∼ 5% in browse may not only act as a feeding deterrent, but also influence the digestibilities. Hence when such leaves are offered as a sole feed they may lower the animal's productivity in terms of body weight gain and wool yield. Treatment with polyethylene glycol-4000 seems viable in reducing the deleterious effects of tannins in top feed, however its economical field application remains to be elucidated.
1. 1. Gross energy digestion and urea recycling were measured in Bedouin goats inhabiting extreme deserts in the Middle East and compared to Swiss Saanen goats. 2. 2. The apparent gross energy digestibility of alfalfa hay and wheat straw in the black Bedouin goat were 6% and 33% respectively higher than in the Swiss goat. 3. 3. When the amount of alfalfa hay fed was restricted to about 60-70% of the ad lib consumption, recycling of urea in the Bedouin goats was maintained at rates (0.44g·N-urea [kg·day]-1) similar to those recorded when alfalfa hay was fed ad lib. In the Swiss goats a 30% drop was recorded. 4. 4. When wheat straw was the only feed, the amount of urea recycled by the Bedouin goats (0.18 g·Nurea [kg·day]-1) was more than twice the amount recycled by the Swiss goats. 5. 5. Supplementing the wheat straw to provide both breeds with equal amounts of digestible energy and nitrogen intake resulted in an increase in the amount of urea recycled in both breeds. The Bedouin goat, however, still recycled twice as much urea (0.3 g·N-urea [kg·day]-1) as the amount recycled by the Swiss goats. 6. 6. It was concluded that under adverse nutritional conditions the Bedouin goat possesses high potentials to both meet its caloric demands as well as to economise its nitrogen metabolism and the two characteristics are complementary to each other.
The purpose of the present review is to provide an integrated examination of the effects of infrequent drinking, water restriction, and heat load on feed intake and utilization in ruminants. The above-mentioned limitations reduce appetite and increase feed utilization. Reduction in rumen motility, rumination activity and saliva secretion reduce passage rate, and hence increase the digestibility of structural carbohydrates. However, contrary to a commonly held view, these digestive responses are directly related to the imposed stress, rather than secondarily related to reduction in feed intake. Although water deprivation, water restriction and heat load similarly affect appetite and digestion, the physiological basis of each is different. Water restriction does not disturb plasma tonicity and its effect is mediated by modification of the food-related drinking. Water deprivation effects are mediated through elevation of plasma osmolarity and secondarily through increase in gut fill and ruminal Na concentration. Heat load effect is mediated through elevation of body temperature and secondarily through increase in gut fill. The response to heat stress is more diverse, since heat load affects both the energy and water metabolism, and varies due to differences among ruminants in insulation properties and body size. As water scarcity and high temperatures are characteristic of dry areas, interactions exist between these two factors, and some examples are given. Goats, having poor insulation capacity, and sheep, with excellent insulation capacity, represent two physiological models. Breeds of ruminants which are well adapted to arid environments demonstrate a greater capability than non-desert breeds to ameliorate the stressful effects induced by water deprivation and heat load. However, as a general rule, the negative effects of water deprivation and heat stress override the benefits from increased feed utilization.
The blood metabolic profile was examined in 2-3 year old non-lactating and non-pregnant Mamber goats consuming Quercus calliprinos (oak), Pistacia lentiscus (pistacia) and Cerafonia siliqua (carob) leaves to determine whether intake of tannin-rich fodder induces subclinical systemic toxicity. Total phenolic and condensed tannin content ranked in the order pistacia > oak > carob. Goats did not exhibit toxic effects following consumption of IO-23 g kg-' day-' of tannin-rich leaves. Metabolite blood concentrations did not differ from goats fed wheat straw, and were within the normal range. Certain serum metabolic indices that are known to be sensitive indicators of damage to the liver (gamma glutamyltranspeptidase, alkaline phosphatase, cholesterol) and kidneys (urea, uric acid, minerals) were within the normal range for goats. Thus, it appears that goats used in this study were well adapted to the nutritional environment and may consume large amounts of tannins (1.1-2.7 g per kg BW per day condensed tannins and 0.4-0.9 g kg-' BW day-' soluble phenolics) without suffering any ill effects.
Effect of 24 h and 48 h of water deprivation on glomerular filtration rate (GFR), and on blood and urine electrolyte levels in Marwari sheep of the Rajasthan desert, India, have been recorded. Body weight, urine volume, GFR and erythrocyte sodium concentration in these animals registered considerable decreases due to dehydration. Both plasma sodium and urinary potassium concentrations remained unaffected. While plasma potassium was somewhat reduced, the potassium in red blood cells increased after 48 h of water deprivation. The most remarkable response was in the concentration of urinary sodium which rose to more than double the normal level.(Received December 12 1975)(Revised December 12 1975)