Practical considerations for ventilating calf barns in winter.

The use of air sampling devices to measure the concentrations of airborne bacteria in clinical investigations and research trials in calf barns has indicated that traditional systems of ventilation are problematic in cold weather. Individual pen designs should have two solid sides, but the front and rear should be as open as possible. Thermal stress should be managed by providing deep bedding and not by enclosing the pen. Air hygiene can be improved by reducing stocking density and using supplemental positive-pressure ventilation systems to deliver small amounts of air to each pen. Implementation of these recommendations can produce calf barns that seem to equal calf hutches in minimizing disease and provide better working conditions for the caregivers.     

玛曲草原牲畜生存的气候生态条件分析及预测模型

随气候变暖,仔畜成活率呈上升趋势,牲畜死损率呈下降趋势。冬季气温对牛犊成活率是主要气候影响因子,暖冬成活率高,冷冬成活率低;盛夏最低气温的变化影响牧草的生长状况,进而影响到牛群抓膘;初冬和晚冬牛群在自然游牧环境下,极端低温天气对牛群膘情的影响十分明显;秋末降水量多,冬季易形成坐冬雪使冬季放牧采食的牛群掉膘严重。初秋日照充足羊易增肥,寡照多雨羊易掉膘;初冬在自然游牧环境下,母羊产羔和羊群膘情受极端低温天气影响明显。气候生态因子通过逐步回归筛选,其影响程度通过通径系数分析用数量表达,由此建立的预测模型就更接近实际情况,对指导畜群生产及合理安排畜群结构提供科学依据。     

犊牛保暖衣的应用与实践

冬季出生的犊牛长时间处于低温条件下会出现冷应激体征,严重者甚至出现死亡,直接影响牧场扩群增效。本文从犊牛耐寒度、持续低温对犊牛的危害分析了研发犊牛保暖衣的必要性,从保暖性、舒适性、透气性、色彩融合性、合体性等方面详细介绍了犊牛保暖衣的设计思路,验证了保暖衣的保暖及增重效果,为牧场提高犊牛福利,降低养殖成本,提高效益提供参考。     

Ventilation of sheep and goat barns

Good ventilation is an important part of any livestock housing system. It may be accomplished by either natural or mechanical means. Generally, except for buildings that must be kept at warm, nonfluctuating temperatures, naturally ventilated cold housing is satisfactory for sheep and goats provided it is dry and draft-free in pen and resting areas, and air exchange is taking place at a rate high enough to remove moisture, gases, and airborne disease organisms from the building. Understanding the importance of site location, building orientation, and principles of ventilation design increases the likelihood of successful barn ventilation.     

Growth Responses of Male Broilers Subjected to High Air Velocity for either Twelve or Twenty-Four Hours from Thirty-Seven to Fifty-One Days of Age

Heat stress contributes to increased late-mortality and decreased growth of broilers grown during hot weather. Tunnel ventilation is commonly used to alleviate heat stress by increasing sensible heat loss. As broilers approach heavy BW (>2.5 kg) in hot weather, operating tunnel ventilation continuously as opposed to only during times of high ambient temperature may improve growth rate and nutrient utilization. This study evaluated growth responses of male broilers subjected to high air velocity (2.79 m/s) for either 12 or 24 h from 37 to 51 d of age. The experimental treatments were 1) control (still air), 2) air velocity of 1.65 m/s (325 ft/min) for 12 h and 2.79 m/s for 12 h, and 3) air velocity of 2.79 m/s (550 ft/min) for 24 h. A cyclical temperature regimen of 25–30–25°C (77–86–77°F) was used with a constant 23°C dew point.Providing continuous high air velocity of 2.79 m/s from 37 to 51 d of age led to a 112-g increase in BW gain and decreased feed conversion ratio by 15 points compared with subjecting broilers to high air velocity of 2.79 m/s for only 12 h. Broilers subjected to both high and low air velocity improved BW gain, feed consumption, and feed conversion over the control birds. These results indicate that continuous ventilation at high air velocity improves BW gain and feed conversion ratio of heavy broilers during the last 2 wk of the grow-out.     

Dairy calf mortality rate: influence of meteorologic factors on calf mortality rate in Tulare County, California.

Monthly calf mortality data for a period of 5.5 years in Tulare County, California, were compared with monthly summarized weather data for that county, using multivariate statistical techniques. In winter, increases in the calf mortality rate (CMR) were significantly associated with cold, wet, windy weather; in summer, greater death losses were associated with hot, dry weather. In general, the calf losses in winter seemed more closely related to weather phenomenon than those in summer. The CMR during a 6-month period (July to December, 1973) were predicted, using equations containing data on the more important weather variables. The predicted CMR significantly differed from the observed death rate during July through September. During October through December, the predicted and observed CMR did not significantly differ. An increase in mortality rate was not predicted for winter, mainly because of low rainfall, and none occurred.     

Factors influencing environmental temperature and humidity in intensive broiler houses during the post‐brooding period

Details are given of the environmental temperature and humidity conditions which occurred in 15 commercial houses containing broilers weighing between 1.4 and 1.8 kg.

The relative humidity of these houses was related to climatic relative humidity. House relative humidity levels which were reduced by increased standards of thermal insulation, by background heating and by correct floor construction, did not fluctuate as widely when temperature and ventilation were controlled by thermostatically operated extraction fans as when the fans were manually controlled. The condition of the litter was correlated with house relative humidity; mean weekly relative humidity levels higher than 72 per cent saturated were associated with caking of the litter surface.

During winter, house temperatures higher than 15° C. were achieved when the outside temperature fell to 0°C. or below only where the ventilation was automatically controlled and where the insulation contained an infill of at least 2.5 cm. thickness of mineral wool. In more poorly insulated buildings, similar temperatures were rarely achieved, even when background heating was provided throughout rearing.

Studies of temperature gradients at floor level in broiler houses showed that these were partly due to large and non‐baffled air inlets whose air throughputs were affected by variations in wind speed and direction. Data of house temperatures in relation to windspeed suggest that air velocities through baffled inlets should be at least 150 m./min. at the point of greatest restriction to air flow. However, if air inlet velocities of this magnitude are used, careful design is necessary in order to prevent draughts at bird level.

Observations are also presented on the incidence, causes and effects of structural condensation in broiler houses.     

Measures of herd health and productivity in Ontario cow-calf herds

A cohort of cows and heifers in 180 separate breeding herds from 170 randomly sampled farms was followed from the 1986 breeding season through to the weaning of their calves in 1987. Data were collected from farm records, survey information collected during farm visits, and provincial government weaning-weight records.

“Kilograms of calf weaned per female-exposed-to-breeding” was calculated as a summary measure of herd productivity. The lowest 25% of cow-herds produced less than 160 kg of calf weaned per cow-exposed-to-breeding, while the highest 25% exceeded 205 kg.

Overall calf crop was 78.1% for cows and 78.5% for heifers. The 25th, 50th, 75th, and 90th percentile estimates for rates, which were components of calf crop (e.g. calving rate), were estimated. The component rates that most influenced calf crop were culling rate for cows and stillbirth rate for heifers.

     

Vehicle design and thermal comfort of poultry in transit

1. Four second‐generation artificial chickens (Glorias) simulated the sensible heat exchanges, H, of pullets and end‐of‐lay hens which they accompanied throughout commercial transit in different sites of the loads.

2. Data from two summer and two winter journeys on each of 5 naturally‐ and 2 fan‐ventilated vehicles were used to derive general equations to predict H and temperature lift for each vehicle.

3. From these, air movement, V, within the crates was calculated together with predicted H at ambient temperatures to compare the thermal comfort of the vehicles.

4. All naturally‐ventilated vehicles were over‐ventilated in motion, with mean V ranging from 0.9 to 2.4 m/s within the crate, and maximum V of 6.0 m/s resulting in negligible temperature lift above ambient. Poorly‐feathered hens were, consequently, extremely cold‐stressed in winter. When stationary, vehicles with a central passage that enabled the ‘stack effect’ to operate were thermally comfortable provided V was kept low. Designs stocked over die whole floor area of the vehicle were too hot.

5. Fan‐ventilated vehicles had a similar range of H whether stationary or in motion. The mean V of 1 to 2 m/s of bird‐warmed air maintained satisfactory thermal conditions most of the time.

6. For current designs of poultry vehicle stocked at commercial rates, V should normally be between 0.3 and 1.0 m/s; air temperature near pullets or broilers should be 10.15°C and near poorly‐feathered hens 22–28°C. Suitable ventilation rates are likely to be in the range 100 to 600 m³ per hour. It is strongly recommended that appropriate temperature monitoring systems be fitted on all vehicles.     

The effects of temperature on broilers: Ventilation rates for the application of temperature control

1. Application of the temperature recommendations from experimental evidence necessitates knowledge of the minimum ventilation rate requirements of the birds, since control of house temperature for finishing broilers in practice is through modulation of ventilation rate in insulated buildings.

2. The minimum ventilation rate requirement was found to be 1.5(( 10^‐4 m³/s per kgW ^0–75 (W = body weight), or 2 m³/s per tonne of food used per day, in three experiments using a total of 33 280 broilers.

3. The first limiting factor governing ventilation rate is often the ammonia concentration in the house air, and under British climatic conditions, the minimum ventilation rate may need to be exceeded after the birds are about 5 weeks of age.     

Conventional versus high-flow oxygen therapy in dogs with lower airway injury

Dogs with lower airway pathology that present in respiratory distress often receive oxygen therapy as the first line of treatment regardless of the underlying cause. Conventional “low-flow” systems deliver oxygen with a maximum flow rate of 15 L/minute. Traditionally, when an animal’s respiratory status does not improve with conventional oxygen therapy and treatments for underlying disease, options might be limited to either intubation and mechanical ventilation or humane euthanasia. High-flow oxygen therapy (HFOT) has been gaining popularity in veterinary medicine as an alternative route of oxygen supplementation for animals that require support beyond conventional therapy. High-flow oxygen therapy can supply a mixture of air and oxygen via a heated and humidified circuit. It is user friendly and can be used in an environment in which mechanical ventilation is unavailable.This review article is written for emergency doctors and general practitioners who lack access to mechanical ventilation. This article briefly reviews pertinent respiratory physiology, traditional oxygen supplementation techniques, the physiology of HFOT, and the limited evidence available in veterinary medicine regarding the use of HFOT, its applications, and limitations. Guidelines for the use of HFOT are suggested and HFOT is compared to conventional therapy.     

Ventilation rates in large commercial layer hen houses with two-year continuous monitoring

1. Ventilation controls the indoor environment and is critical for poultry production and welfare. Ventilation is also crucial for assessing aerial pollutant emissions from the poultry industry. Published ventilation data for commercial layer houses have been limited, and are mostly based on short-term studies, mainly because monitoring airflow from large numbers of fans is technically challenging.

2. A two-year continuous ventilation monitoring trial was conducted at two commercial manure belt houses (A and B), each with 250?000 layers and 88 130-cm exhaust fans. All the fans were individually monitored with fan rotational speed sensors or vibration sensors. Differential static pressures across the house walls were also measured. Three fan performance assessment methods were applied periodically to determine fan degradations. Fan models were developed to calculate house ventilations.

3. A total of 693 and 678 complete data days, each containing >16?h of valid ventilation data, were obtained in houses A and B, respectively. The two-year mean ventilation rates of houses A and B were 2·08 and 2·10?m³?h^?1?hen^?1, corresponding to static pressures of ?36·5 and ?48·9?Pa, respectively. For monthly mean ventilation, the maximum rates were 4·87 and 5·01?m³?h^?1?hen^?1 in July 2008, and the minimum were 0·59 and 0·81?m³?h^?1?hen^?1 in February 2008, for houses A and B, respectively.

4. The two-year mean ventilation rates were similar to those from a survey in Germany and a 6-month study in Indiana, USA, but were much lower than the 8·4 and 6·2?m³?h^?1?hen^?1 from a study in Italy. The minimum monthly mean ventilation rates were similar to the data obtained in winter in Canada, but were lower than the minimum ventilation suggested in the literature. The lower static pressure in house B required more ventilation energy input. The two houses, although identical, demonstrated differences in indoor environment controls that represented potential to increase ventilation energy efficiency, and reduce carbon footprints and operational costs.     

多层楼房式猪舍自动化通风与臭气净化系统的设计与应用

楼房式猪舍因其节约土地、方便管理等突出优点,在越来越多的地方被采用。由于楼房式养殖的饲养密度更大,所以其通风设计与舍外场区环境控制显得尤为重要。文章针对大跨度小单元楼房式猪舍,设计了一种通风与臭气净化相结合的新型通风工艺。夏季采用湿帘-定速风机模式通风降温,保证高效率通风降温;冬季采用檐下通风小窗-吊顶通风窗-变频风机模式,变频风机转速随着氨气浓度上升而相应加大,这种方式可以保证通风效果的同时确保最大程度减少舍内热量损失。在出风端,增加臭气净化处理工艺,利用添加生物菌剂的水循环过滤墙将猪舍排出的臭气通过水洗过滤,降低排出气体中的臭味物质浓度,改善养殖场区空气环境。整套工艺采用智能化控制,实现对系统的精准控制,同时节能降耗,提高养殖场的总体效益。     

The physiological and physical status of single calves at birth in a dairy herd in New Zealand

AIM: To determine the physiological status of calves at birth and the perinatal factors that might predispose newborn calves to debility and death, using criteria previously established for newborn lambs.

METHODS: Friesian mixed-aged cows and heifers on a dairy farm in New Zealand that were close to calving were separated from the main herd and observed 24 h a day until they calved. Cows in which labour did not progress for over 1 h or which were in distress were assisted. About 12–13 min after birth, rectal temperature was measured and a blood sample was taken from each calf. The packed cell volume (PCV) and plasma lactate, glucose and fructose concentrations were determined. The time to stand for each calf and the air temperature and weather conditions at birth were recorded.

RESULTS: The parameters measured were within normal ranges for newborns for the majority of calves. Calves sired by an Angus bull and born to heifers (AngusX) had significantly higher plasma lactate and fructose concentrations than Friesian calves born to cows, but there were no significant differences between the two breeds in any of the other parameters measured. Calves of both breeds born with assistance had significantly higher plasma lactate concentrations than those born without. Friesian calves that were assisted at birth had significantly lower PCvs and took significantly longer to stand than calves born without assistance. Assisted AngusX calves were significantly heavier than their unassisted counterparts. Calves born during windy and wet weather and when air temperatures were below 10°C had lower rectal temperatures, took longer to stand and had higher plasma glucose concentrations than those born in dry weather and when air temperatures were above 10°C.

CONCLUSIONS: Calves with physiological parameters outside the normal range had experienced difficult labour and/or intrapartum hypoxaemia. Placental insufficiency and maternal undernutrition during late pregnancy did not apparently contribute to neonatal problems in the present study.     

Association of environmental air contaminants with disease and productivity in swine.

A cross-sectional epidemiologic study associating air quality with swine health was conducted on 28 swine farms in southern Sweden. Correlation of housing air environment to swine diseases and productivity (data collected over the preceding 12 months) were investigated. The most prevalent swine health problems detected at slaughter were pneumonia and pleuritis. In farrowing and nursery operations, the most prevalent problem was neonatal pig mortality. Several air contaminants (dust, ammonia carbon dioxide, and microbes) were found to be correlated with these swine health problems. Maximal safe concentrations of air contaminants were estimated on the basis of dose-response correlation to swine health or human health problems. Recommended maximal concentrations of contaminant were: dust, 2.4 mg/m3; ammonia, 7 ppm; endotoxin, 0.08 mg/m3; total microbes, 10(5) colony-forming units/m3; and carbon dioxide, 1,540 ppm. The overall quality of the ventilation system was correlated with lower concentration of ammonia, carbon dioxide, microorganisms, and endotoxin, but not with dust concentrations. High animal density was related to high ammonia and air microbe concentrations. Animal density measured as kilograms of swine per cubic meter (compared with kilograms of pig weight or swine per square meter) had the highest correlation to animal health and air contaminants.     

冬春季暖棚舍饲对母羊体重损失及产羔性能的影响

研究冬春季暖棚舍饲对母羊体重损失及产羔性能的影响。试验分别于2011、2012和2013年冬春季在内蒙古锡林郭勒盟太仆寺旗进行,在当地选用2户临近牧户,每户挑选120只母羊,随机分为2组,分别为传统棚+放牧组(TS,对照)、改造暖棚+舍饲组(WS)。参试母羊夏秋季白天自由放牧,晚上归牧后圈在传统棚内;到冬春季TS组饲养方式不变,WS组舍饲在简易改造暖棚。整个试验期间,2组母羊及其羔羊的补饲饲料组成及饲喂量相同。试验结果表明,WS组母羊体重较TS组高1.6 kg(P=0.004),体重损失较之少22 g/d(P=0.005);母羊体重损失在12-1月份最严重,但经第一年(2011)饲养损失程度显著缓解(P<0.001),体重损失随棚圈积温升高而减少。TS组的年均产羔数、羔羊体重及其日增重均显著低于WS组(P=0.020;P=0.0005;P=0.0001),初生重及日增重随着饲养年份的延后而增加(P<0.001);产羔率、羔羊存活率和双羔率随棚圈积温的升高而增大。以上结果表明,冬春季暖棚舍饲可显著减少母羊越冬体重损失,并提高产羔力,进而提高家庭牧场收入,保护退化草场。更重要的是,冷季舍饲有助于改变牧民的传统养殖观念,从“生存观”转向“生产观”。建议,西北牧区冷季绵羊圈舍适宜积温应高于-40 ℃·d或基本温度高于2 ℃。     

Effects of ventilation regimen on the welfare and performance of lactating ewes in summer

A 6-wk trial was performed with thirty-six lactating Comisana ewes during the summer of 2001. The animals were divided into three groups of 12, which were designated low (LVR), moderate (MVR), and programmed (PROGR) ventilation regimens. In LVR and MVR rooms, fans provided 10 ventilation cycles of 12.5 and 25 min/h, respectively, whereas in the PROGR room, the fan was programmed to operate at 30 degrees C air temperature and 70% relative humidity. Mean ventilation rates were 33, 66, and 173 m3/h per ewe in LVR, MVR, and PROGR rooms. Air concentrations of microorganisms and dust and of gaseous pollutants were measured twice weekly. Respiration rate and rectal temperature were monitored throughout the trial at 1430. Behavioral traits of ewes were recorded once per week from 0930 to 1230. Cell-mediated immune response to phytohemagglutinin at d 3, 20, and 40 and humoral response to chicken egg albumin at d 11, 21, 30, and 40 were determined. At d 37, ewes were injected with 2 IU porcine ACTH/kg body weight(0.75) and subjected to blood sampling for evaluation of cortisol concentrations immediately before and 1, 2, and 4 h after ACTH injection. Milk yield was recorded daily. Individual milk samples were analyzed weekly for composition and renneting parameters and fortnightly for bacteriological characteristics. Averages of temperature-humidity index values were 78.9, 76.8, and 74.5 in LVR, MVR, and PROGR rooms, respectively. The LVR and MVR treatments resulted in higher NH3 and CO2 air concentrations than PROGR treatment (P < 0.05). The LVR and MVR ewes had higher rectal temperatures than PROGR ewes (P = 0.001). LVR animals also exhibited higher idling compared to PROGR (P < 0.01) and lower feeding times than MVR (P < 0.05) and PROGR animals (P < 0.01). Ewes under the LVR treatment displayed significant lower averages of antibody titers and higher plasma cortisol levels than PROGR (P < 0.01) and MVR ewes (P < 0.05) 60 min after ACTH injection. The LVR treatment resulted in lower yields of milk (P < 0.01) and reduced feed efficiency (P < 0.01) than PROGR treatment. Results suggest that a fan-ventilated system, providing ventilation cycles during the warmest hours of the day and the night at a mean ventilation rate of 66 m3/ewe per hour, may sustain the performance and welfare in lactating ewes raised in warm climates during summer. A ventilation regimen, programmed to operate over upper critical air temperature and relative humidity, may be economically unattractive under these conditions.     

Nitrofuran Production Efficiency In Chickens

Two nitrofuran feed additives, 0.011% nihydrazone and a combination of 0.0055% nitrofurazone and 0.0008% furazolidone, improved weight gains and feed conversions in chickens with “air sac infection.” Both nitrofurans caused a significant reduction in the total chickens condemned at the dressing plant from this disease, but nihydrazone gave the best results.

Nihydrazone^*, a new nitrofuran feed additive for chickens, was found by Wolfgang et al. (1) to be effective against coccidiosis due to Eimeria tenella and E. necatrix. In chickens nihydrazone was shown by Edgar et al. (2) to result in fewer chickens condemned from “air sac infection” than with any other drug used. Rosenberg et al. (3) found nihydrazone caused significant reduction in condemnations due to this disease. Cosgrove (4) showed that nihydrazone prevented an outbreak of cecal coccidiosis, reduced the incidence of “air sac infection,” improved weight gains, feed conversions and livability. Bierer (5) found nihydrazone active against fowl typhoid.

Harwood et al. (6) reported bifuran^** effective against E. tenella and E. necatrix coccidiosis and it has been used commercially for this purpose. Bierer (5) (7) found Bifuran^*** active in prevention of pullorum disease and fowl typhoid in chicks.

The mode of action of nihydrazone and nitrofurazone against E. tenella coccidiosis was shown by Johnson and Van Ryzin (8).

This production efficiency study was undertaken to evaluate nihydrazone and bifuran in the presence of “air sac infection” and concomitant diseases under field conditions. Camden (9) states that the only satisfactory test of a drug is the performance it gives under field conditions.

Nihydrazone (1) (5) and Bifuran (5) (6) have both antibacterial and antiprotozoal activity and under field conditions, normal densities of bacterial and other parasitic organisms are encountered (9). Thus a coccidiostat having antibacterial and antiprotozoal properties is desirable (7).

     

The ERA Strain of Rabies Vaccine

An antigenic extinction trial in cats showed that the ERA rabies vaccine had superior antigenic properties over Flury H.E.P. C.E.O. and killed tissue culture rabies vaccine.

Dogs and cats on a duration of immunity study of ERA rabies vaccine were challenged with fox salivary gland “street” rabies virus. The results of this challenge show a duration of immunity of five years in dogs and four years in cats.

Vaccination of dams in late pregnancy with ERA rabies vaccine resulted in transference of maternal antibody to the newborn, in both cattle and dogs. This maternally derived antibody interfered with the successful active immunization of the young calf. Calves free of antibodies for rabies could be successfully vaccinated as early as 17 days of age and were able to withstand a challenge with virulent “street” rabies virus two years later.

     

西北地区冬季肉牛养殖环境控制及管理措施研究

为了改善西北地区冬季肉牛养殖的环境、福利状况,提高肉牛生产水平,试验将环境控制(控制牛舍通风、铺加垫料、增加清粪次数)和管理措施(饮用温水)应用于实际生产,并通过检测牛舍环境、牛体清洁度、日增重等指标来评价改进措施的综合应用效果。结果表明:控制牛舍通风、铺加垫料、增加清粪次数能显著提高牛舍内最低气温和地面温度,对牛舍内日平均气温没有显著影响;降低舍内风速的同时增加了湿度、二氧化碳和氨气浓度,但总的来说在一定程度上改善了牛舍内的环境状况;对牛体清洁度、日增重没有显著影响。说明给牛饮10℃的温水能显著提高肉牛日增重,值得推广。