The effects of stock crate design and stocking density on environmental conditions for lambs on road transport vehicles

AIM: The aim of this study was to evaluate the potential of variations in stock crate design (especially ventilation) and stocking density on road transport vehicles for reducing the risk of environmental stress for lambs during long-haul transport in hot weather. METHODS: In Experiment 1, lambs were transported on vehicles fitted with either a newer-design aluminium crate comprising a three-deck truck and four-deck trailer, or an older-design, more open, steel crate of a three-deck truck and three-deck trailer. In Experiment 2, lambs were transported on newer-design vehicles at either standard stocking density (0.20 m2 per 35 kg lamb) or at a 20% lower density (0.26 m2 per 35 kg lamb). In each experiment, each journey was replicated twice and consisted of travel periods and stationary periods designed to emulate conditions associated with an inter-island ferry crossing. Air ammonia concentrations and temperature and humidity were monitored within six pens on each vehicle, and the temperature-humidity index (THI) was calculated. RESULTS: Ammonia concentrations were variable and generally 50 ppm, and did not vary significantly with treatment. The THI increased when the vehicles were stationary, especially under conditions designed to emulate an enclosed ferry deck. The ambient temperature during Experiment 1 was moderate (up to 21 degrees C), and THI was slightly lower in the older-design crate. High ambient temperatures (up to 33 degrees C) were present during Experiment 2, and THI was significantly lower at the lower stock density. During a 3-h stationary period, the peak THI at standard stocking density was 91.0, compared with 84.9 for the low density treatment (p<0.001). CONCLUSIONS: For standard road transport vehicles used for long-haul transport of lambs, lowered loading density may be of considerable benefit in alleviating conditions that increase the risk of lamb deaths during inter-island transport on hot days.     

温湿度对乳牛产乳量的影响

研究了夏季高温中温、湿度对中国黑白花乳牛生产性能的影响。结果表明,夏季气温27℃、温湿指数(THI)超过69时,导致该品种牛产乳量下降     

The effects of temperature and humidity on the off-host survival of Psoroptes ovis and Psoroptes cuniculi.

The effects of both temperature and humidity on the survival of the mites Psoroptes ovis and Psoroptes cuniculi were considered in laboratory assays. When P. ovis and P. cuniculi were maintained at 95% humidity, maximum survival decreased linearly with increasing temperature, from approximately 15 days at 9 degrees C to 5 days at 30 degrees C. There was no significant difference between P. ovis and P. cuniculi in the effects of temperature on maximum survival. Adult male P. ovis and P. cuniculi had lower mean maximum survival than any of the other life cycle stages. There was a small but significant effect of humidity on survival for P. cuniculi; LT50 values were greater at 75-85% r.h. than at 55-65% r.h. The influence of off-host survival and the infestation of naive sheep from mites in the environment on the epidemiology of sheep scab are discussed.     

Clinical, cardiopulmonary and haemocytological effects of xylazine in goats after acute exposure to different environmental temperature and humidity conditions

This study was carried out to assess the influence of xylazine administration on clinical, cardiopulmonary and haemocytological variables after acute exposure to different environmental conditions. Xylazine hydrochloride was administered intravenously at 0.1 mg/kg body mass to 6 clinically healthy, castrated male goats. All animals were exposed for 60 min to 3 sets of climatic conditions: 14 degrees C, 33% relative humidity; 24 degrees C, 55% RH, and 34 degrees C, 65% RH. The variables that were measured for a period of 60 min after xylazine administration were sedation, analgesia, salivation, urination, ventilation rate, heart-rate, mean arterial blood pressure, oesophageal temperature, haematocrit, mean corpuscular volume and mean corpuscular haemoglobin concentration. Xylazine induced sedation, analgesia, salivation and urination independently of the 3 environmental conditions. Environment had no influence on the onset, duration and recovery from sedation. In the 14 degrees C environment, xylazine resulted in a significant decrease in ventilation and heart-rate from baseline values. Significant changes in mean arterial blood pressure, haemoglobin concentration, mean corpuscular volume, haematocrit and red cell count were observed in the 3 environments. Total plasma protein was significantly altered at 24 degrees C and 34 degrees C. Acute exposure of goats to different environmental conditions had no significant influence on the clinical, cardiopulmonary and haemocytological variables. Physiological changes induced by xylazine were therefore independent of the environment.     

Negative effects of stress immediately before slaughter on pork quality are aggravated by suboptimal transport and lairage conditions

The objectives of the present experiment were 1) to study the effects of transport conditions and lairage duration on stress level, muscle glycolytic potential, and pork quality; and 2) to investigate whether the negative effects of high stress immediately preslaughter are affected by preceding handling factors (transport and lairage). In a 2 x 2 x 2 factorial design, halothane-free pigs (n = 384) were assigned to either short (50 min) and smooth or long (3 h) and rough transport; long (3 h) or short (<45 min) lairage; and minimal or high preslaughter stress. Pigs were processed in eight groups (48 pigs per group) on various days at a commercial plant. Blood samples were taken at exsanguination to measure plasma cortisol and lactate concentrations. Muscle pH and temperature were measured at 30 and 40 min, respectively, and both were measured at 3 h, postmortem. A LM sample was taken 135 min postmortem to estimate glycogen content and rate of glycolysis. Pork quality attributes were assessed 23 h postmortem. Short transport increased cortisol when followed by short lairage (transport x lairage; P < 0.01). Long transport, but not lairage (P > 0.30), tended to increase (P = 0.06) muscle glycolytic potential. Long transport tended to increase (P = 0.08) electrical conductivity, and decreased a* (P < 0.01) and b* (P < 0.02) values. Decreasing lairage from 3 h to <45 min decreased (P < 0.05) the L* value, but it did not (P > 0.10) affect other pork quality traits. High stress decreased (P < 0.001) muscle glycolytic potential, and increased (P < 0.001) plasma lactate, cortisol, muscle temperature, rate of pH decline, and ultimate pH. Except for decreased (P < 0.001) b* values, pork color was not (P > 0.40) affected by high stress, but water-holding properties (measured by electrical conductivity, filter paper moisture, and drip loss) were impaired (P < 0.001) by high stress. Fiber optic-measured light scattering and Warner-Bratzler shear force were not (P > 0.12) affected by any treatment. Comparisons with the "optimal" handling (short transport, long lairage, and minimal stress) revealed that, with regard to water-holding properties, the negative effects of high stress were aggravated by suboptimal transport and lairage conditions. High stress alone increased electrical conductivity by 56%, whereas high stress in combination with short lairage led to an 88% increase. However, high preslaughter stress contributed most and was the major factor responsible for reductions in pork quality.     

The microclimate of the canine coat: the effects of heating on coat and skin temperature and relative humidity

The coat of seven ‘Landseer’ Newfoundland dogs was irradiated using an infra-red source for 25 min. In each dog, at a site of each colour (black and white), skin and coat temperatures were monitored, and coat air humidity measured with a specially designed instrument. Almost no differences were noted at sites with differing coat colour. Skin temperature rose from 35 °C to a plateau at 39 °C, whilst coat temperature rose from 30 °C to 41 °C. Relative humidity of coat air initially rose, then fell significantly (P < 0.001). The absolute humidity initially almost doubled (P < 0.001), but then fell, although remaining significantly higher than that of ambient air. It was concluded that an initial burst of sweating was followed by lower but continuing secretion. This was not, however, of great importance in cooling. In a separate study the skin temperature of black coated dogs exposed to bright sunshine was explored. The mean temperature was almost identical to that of the plateau skin temperature noted in Newfoundland dogs.     

Effects of vehicle movements during transport on the stress responses and meat quality of sheep

Two groups of 26 lambs were transported for 15 hours either on smooth highways or on rougher secondary roads. Nine of the animals in each group were monitored for heart rate and the plasma levels of cortisol, creatine kinase and lactate dehydrogenase, before the journey began, after four, eight and 12 hours and at slaughter. The pH of the meat was measured 45 minutes and 24 hours postmortem and its colour was assessed 24 hours postmortem. The lambs transported on smooth roads had a lower heart rate and lower plasma cortisol concentrations after eight and 12 hours than the lambs transported on rougher roads. Twenty-four hours after slaughter the pH of the meat of the lambs transported on smooth roads was lower than that of the lambs transported on rougher roads.     

Effects of external thermal manipulation on laminar temperature and perfusion scintigraphy of the equine digit

AIMS: To assess the effects of external thermal manipulation on the soft-tissue and vascular perfusion of the equine digit using nuclear scintigraphy and documented tissue temperatures. METHODS: Six horses were used in a randomised crossover design. Each horse was treated with external heat (47 degrees C) or external cold (4 degrees C) applied to a digit for 30 minutes. The opposite front foot was untreated and used for control measurements. Nuclear scintigraphy was performed before, during, and after therapy to assess vascular and soft-tissue perfusion to the digit in response to therapy. Dorsal hoof wall laminar-tissue temperatures were recorded before, during, and after therapy using a thermistor. RESULTS: Treatment with topical cold therapy significantly decreased soft-tissue perfusion of the digit to 80.5% of the pre-cooled values. Conversely, the application of external heat significantly increased soft-tissue perfusion of the digit 25.1% above the pre-heated values. Vascular perfusion showed similar, but not statistically significant trends. External cold application to the digit caused a significant mean decrease in laminar-tissue temperatures of 11.6 degrees C during therapy, while external heat application to the digit caused a significant mean increase in laminar-tissue temperatures of 3.9 degrees C. CONCLUSION: The external application of heat and cold to the normal equine foot could effectively alter soft-tissue perfusion and laminar-tissue temperatures within 30 minutes of treatment. The application of hot water and ice water to the digit was a safe, well-tolerated, and economical therapy. CLINICAL RELEVANCE: Cooling the foot could decrease enzymatic reactions associated with laminitis, and warming could increase local perfusion when desired.     

温湿度对亚洲小车蝗飞行能力及主要能源物质利用的影响

本研究采用昆虫飞行数据微机采集系统(飞行磨)吊飞方法,测定了温、湿度对10日龄亚洲小车蝗(Oedaleus asiaticus)雌雄成虫的飞行能力及主要能源物质利用的影响。结果表明,在环境温度为28℃、相对湿度(RH)为60%时,10日龄亚洲小车蝗成虫表现出最优的飞行能力,单个个体的最大飞行时间、最大飞行距离和最大飞行速度分别可达1.62h、9.87 km和2.03 km·h~(-1)。在温度16℃以下或28℃以上,其飞行能力明显降低。在40%~80%RH时,成虫均能进行正常的飞行活动。环境温、湿度会显著影响亚洲小车蝗成虫飞行能源物质的消耗情况(P0.05)。在最适的温、湿度条件下,小车蝗飞行所需的能源物质(甘油三酯)最少,其飞行单位距离消耗的甘油三酯也最低,能源利用效率最高。较高或较低的温、湿度条件,能源物质的消耗都显著高于最适条件。飞行能源物质利用效率的不同是导致其在不同温、湿度下飞行能力产生差异的主要原因之一。     

The effect of temperature and humidity on longevity of metacercariae of Fasciola gigantica

Studies were undertaken on the viability of the metacercariae of Fasciola gigantica when stored in water at 13^˚C for periods up to 23 weeks, exposed to the sunlight for up to 8 h or stored at a range of temperatures and humidities for up to 10 weeks. Excysted metacercariae were catergorized microscopically as viable (motile and undamaged), dubious (not motile and undamaged) or dead (visible necrosis). The infectivity of viable and dubious metacercariae and unselected reference metacercariae held in water at 7^˚C for 20 days or longer was assessed by comparing numbers of flukes recovered from infected Merino sheep. Mean recovery rates were 54.6%, 7.2% and 37.2%, respectively, for viable, dubious and unselected metacercariae. Metacercariae immersed in water remained viable longer than those allowed to desiccate. Viability was promoted by decreasing temperature and increasing humidity. Exposure to direct sunlight killed metacercariae within 8 h. Results indicated that in lowland Indonesian irrigated rice paddies, metacercariae immersed in water are likely to survive for less than 5 weeks while those that become desiccated will survive less than 2 weeks. This information, together with the option of exposing fresh rice stalks to direct sunlight before feeding them to livestock, can assist farmers in reducing infection with F. gigantica.     

Effects of xylazine on acid-base balance and arterial blood-gas tensions in goats under different environmental temperature and humidity conditions

The effects of acute exposure to 3 different temperature and humidity conditions on arterial blood-gas and acid-base balance in goats were investigated after intravenous bolus administration of xylazine at a dose of 0.1 mg/kg. Significant (P<0.05) changes in the variables occurred under all 3 environmental conditions. Decreases in pH, partial pressure of oxygen and oxyhaemoglobin saturation were observed, and the minimum values for oxygen tension and oxyhaemoglobin saturation were observed within 5 min of xylazine administration. The pH decreased to its minimum values between 5 and 15 min. Thereafter, the variables started to return towards baseline, but did not reach baseline values at the end of the 60 min observation period. Increases in the partial pressure of carbon dioxide, total carbon dioxide content, bicarbonate ion concentration, and the actual base excess were observed. The maximum increase in the carbon dioxide tension occurred within 5 min of xylazine administration. The increase in the actual base excess only became significant after 30 min in all 3 environments, and maximal increases were observed at 60 min. There were no significant differences between the variables in the 3 different environments. It was concluded that intravenous xylazine administration in goats resulted in significant changes in arterial blood-gas and acid-base balance that were associated with hypoxaemia and respiratory acidosis, followed by metabolic alkalosis that continued for the duration of the observation period. Acute exposure to different environmental temperature and humidity conditions after xylazine administration did not influence the changes in arterial blood-gas and acid-base balance.     

The effects of age, environmental temperature and relative humidity on the bacterial flora of the upper respiratory tract in calves

The effects of age, environmental temperature and relative humidity on the bacterial flora of the nose and trachea of calves were investigated by sequential sampling of three groups each of eight Friesian-Holstein male calves kept in three different environmental conditions. All calves were vaccinated with a live attenuated vaccine against infectious bovine rhinotracheitis (IBR) when they were 12 weeks old. Nasal and tracheal swabs were collected at 14-day intervals for bacteriological examinations. The upper respiratory tract of calves started to be colonized by various species of bacteria within the first day of life. Although they were born at different periods of the year, the calves in all three groups had similar bacterial loads in their noses and tracheas when they were 1 day old (P greater than 0.05). The total bacterial colony forming units (BCFU) were highly variable from calf to calf and from one time of sampling to another. Despite these variations, there were age-related increases in the total BCFU in nasal and tracheal swabs in all experiments. These increases were influenced by environmental temperature. Vaccination of the calves with a live IBR vaccine appeared to enhance the bacterial colonization of the upper respiratory tract.     

The rate of spread of sheep scab within small groups of Merino and Dorper sheep

A single Merino sheep, artificially infested with the sheep scab mite, Psoroptes ovis, and a similarly infested Dorper sheep were placed with 9 uninfested Merino or 9 uninfested Dorper sheep respectively during winter and the rate of spread of infestation on the uninfested sheep observed. The same procedure was repeated in summer. It took 14 and 8 weeks respectively in winter before all sheep in the 2 groups displayed lesions of sheep scab, whereas in summer it took 10 and 12 weeks before all sheep had lesions.     

Measurement of the three-axis vibration,temperature, and relative humidity profiles of commercial transport trailers for pigs

The objective of this study was to collect and interpret three-axis acceleration, temperature, and relative humidity data from six locations within commercial transport trailers shipping market-weight pigs. Transport was observed in Kansas (n = 15) and North Carolina (n = 20). Prior to loading, three-axis accelerometers were affixed to six locations on the trailers: top fore (TF), top center (TC), top aft (TA), bottom fore (BF), bottom center (BC), and bottom aft (BA) compartments. Data were post-processed to calculate root-mean-square (RMS) accelerations and vibration dose values (VDV) in the vertical direction and the horizontal plane. These values were compared with exposure action values (EAV) and exposure limit values (ELV), vibration levels deemed uncomfortable and potentially dangerous to humans. Additionally, RMS and VDV were compared among the trailer compartments. The vertical RMS accelerations for all compartments exceeded the EAV for loads measured in Kansas, and for the majority of the compartments measured in North Carolina. Many compartments, specifically the BA compartment from all trips, exceeded the vertical ELV. Regardless of where the data were collected, fewer compartments exceeded the EAV in the horizontal orientation. Only BA compartments exceeded the ELV in the horizontal orientation. There were Area × Level interactions for vertical and horizontal RMS and VDV (P < 0.01). The BF compartment had a greater vertical RMS value than the TF, TC, and BC (P < 0.02) compartments, but did not differ (P = 0.06) from the TA compartment. The vertical RMS of the TA compartment did not differ from the TF, TC, and BC compartments (P > 0.13). The BF compartment had a greater (P = 0.02) vertical VDV value than the TC location, but did not differ from the other locations (P > 0.16). All other locations did not differ in vertical VDV (P > 0.12). The BF compartment had greater horizontal RMS than the TC and TA compartments (P < 0.01), but did not differ from TF and BC compartments (P > 0.12). All other compartments did not differ in horizontal RMS (P > 0.34). All compartments, aside from the BA compartment, did not differ in horizontal VDV (P > 0.19). Vibration analyses indicated the BA compartment had the greatest vertical and horizontal vibrations and a large percentage of the compartments exceed the EAV and ELV, which indicated pigs may have experienced uncomfortable trips that could cause discomfort or fatigue.