Housing and Environment for Dairy Calves

Many cases of poor health in calves have been traced to bad management and inadequate ventilation in the calf nursery. Important management principles for improved calf health include calf housing isolated from the adult herd and periodic depopulation and sanitizing of the calf nursery area. In good weather, low-cost calf rearing portables such as the “calf hutch” can provide alternative housing during the cleanup period.

Calf nursery ventilation systems must have flexibility to give the full winter-to-summer range of controlled ventilation rates and critical air inlet adjustments. Earlier recommendations were for three stepped ventilation rates of 3.3, 6.6 and 24 L/s per calf to cover the range from cold winter to warm summer weather. Later recommendations are for a simpler two stepped fan system starting at 6.7 L/s (continuous winter rate) and increasing to 50 L/s for temperature control in warm to hot weather.

Even with the best insulated construction, increased supplementary heating is required to support this increased continuous winter ventilation. To save energy the heating must be controlled to stop before the higher-rate ventilation starts. Other design features for more uniform temperatures and improved calf nursery ventilation include: 1) preheating the ventilation air before it enters the calf room, 2) distributing air to the ceiling with round holes and adjustable slots adjusted to give at least 4 m/s inlet velocity, 3) using a properly sized centrifugal fan running continuously to exhaust air from near the floor in winter and 4) protecting air intakes and fan openings from the effects of wind. Air recirculation systems and variable-speed fans are not recommended.

     

Air hygiene in stables. 1: Effects of stable design, ventilation and management on the concentration of respirable dust

The concentration of fungal spores, the main constituents of respirable dust in stables, is determined by rates of release from fodder and bedding and rate of clearance, principally by ventilation. This paper outlines the principles that govern the application of natural ventilation to the control of air hygiene in barns and individual boxes for horses. When release rates are low, ventilation rates over four air changes per hour are satisfactory. Ventilation was satisfactory in individual boxes but usually unsatisfactory in barns and specific recommendations are made for improvement. Preliminary observations in stables with clean, well-managed bedding revealed only small differences between straw, wood shavings and paper. In these circumstances hay tended to be the major source of respirable spores.     

Airborne transmission of classical swine fever virus under experimental conditions

Sixty-one pigs were housed in an isolation unit with three compartments and five pens. Each compartment had its own ventilation system resulting in air currents flowing from compartment A (pens 1 to 3) towards compartment B (pen 4), but not towards compartment C (pen 5). Classical swine fever virus was introduced by the experimental inoculation of one pig in the middle pen (pen 2) of compartment A. The virus infected the pigs in pen 4, following the prevalent air currents, and the compartmentalisation had only a retarding effect on the transmission of the virus. The absence of infection in the pigs in pen 5, which was not different from pen 4 except for the ventilation system, indicates that the spread of virus was affected by the air currents.     

Transmission of bovine viral diarrhoea virus by unhygienic vaccination procedures,ambient air,and from contaminated pens

Knowing how bovine viral diarrhoea virus (BVDV) infection spreads via indirect contacts is required in order to plan large-scale eradication schemes against BVDV. In this study, susceptible calves were exposed to BVDV by an unhygienic vaccination procedure, by ambient air and from contaminated pens. Primary BVDV infection was observed in two calves vaccinated with a vaccine against Trichophyton spp that had been contaminated by smearing nasal secretion from a persistently infected (PI) calf on the rubber membrane and penetrating it twice with a hypodermic needle. Four other calves, housed in pairs in two separate housing units near a PI calf for one week--at distances of 1.5 and 10 m, respectively--became infected without having direct contact with the PI calf. Furthermore, two of the three calves housed in a pen directly after removal of a PI calf, but without the pen being cleaned and disinfected, also contracted primary BVDV infection, whereas two calves that entered such a pen four days after removal of another PI calf, did not. In herds where most animals are seronegative to BVDV, indirect airborne transmission of BVDV or contact with a contaminated housing interior may be an important factor in spreading of the virus, once a PI animal is present. However, the spreading of BVDV within herds can be stopped by identifying and removing PI animals and also by ensuring that susceptible breeding animals do not become infected during this procedure. In contrast, injectables contaminated with BVDV may prove to be a significant vector for spreading the infection, not only within an infected herd but, most importantly, also between herds. In our opinion, it is questionable whether medicine bottles, once opened and used within an infected herd, should be used in other herds. In any case, prior knowledge of a herd's BVDV status will help practising veterinarians and technicians to undertake appropriate hygienic measures.     

Efficient surveillance of pig populations using oral fluids

Currently virus surveillance in swine herds is constrained by the cost-effectiveness and efficiency of sampling methods. The objective of this study was to assess the value of using oral fluids collected by barn personnel as a method of surveillance based on PCR testing. Approximately 12,150 pigs in 10 wean-to-finish barns on 10 farms were monitored for the presence of porcine circovirus type 2 (PCV2), porcine reproductive and respiratory syndrome virus (PRRSV), influenza A virus (IAV), and Torque teno virus genogroups 1 (TTV1) and 2 (TTV2) by sampling oral fluid specimens. Oral fluid samples were collected from 6 pens at each site starting at the time of pig placement (～3 weeks of age) and continuing thereafter at 2-week intervals for a period of 18 weeks. Data were analyzed both on a pen basis and barn basis. Overall, 508 (85%) samples were positive for PCV2, 73 (12%) for PRRSV, 46 (8%) for IAV, 483 (81%) for TTV2, and 155 (26%) for TTV1 during the study period. The estimated arithmetic means of the quantitative PCR-positive oral fluids for PCV2, PRRSV, and IAV were 1×10(4.62), 1×10(4.97), and 1×10(5.49)per ml. With a single exception, all barns were positive for PCV2 and TTV2 at every sampling point in the study. Virus detection varied among barns, particularly for IAV and PRRSV. The pen level, cumulative distribution of agent combinations between all 10 barns were statistically different. The most commonly observed patterns were PCV2+TTV2 (239 pen samples, 40%), PCV2+TTV1+TTV2 (88 pen samples, 15%), and PCV2 alone (66 pen samples, 11%). This "proof-of-concept" project showed that a variety of viruses could be detected either intermittently or continuously in pig populations and demonstrated that barn herd virus status is highly variable, even among barns in the same production system. Oral fluid sampling is a promising approach for increasing the efficiency and cost effectiveness of virus surveillance in swine herds.     

哺乳期犊牛健康管理

哺乳期犊牛是奶牛生命周期的开始,也是奶牛整个生命周期中最为脆弱的阶段,其健康状况可直接影响牧场的可持续发展和经营效率。在哺乳期,犊牛可面临多种疾病的挑战,但消化道疾病和呼吸道疾病是全球奶牛养殖业面临的共性问题。本文对哺乳期犊牛健康状况、初乳管理、犊牛腹泻和呼吸道疾病的管理进行了梳理,并对其防控提出了建议。初乳管理方面分析了影响初乳质量的因素、初乳储存与处理和饲喂管理;犊牛健康管理部分叙述了产圈管理、饲养环境和饲喂方式、营养及饲喂管理、疫苗免疫、通风、疾病早期诊断、应激管理和患犊管理。     

寒区犊牛岛的设计及使用效果初探

为了提高寒区犊牛的健康水平和成活率,试验设计了一种适用于寒区的犊牛岛,在气温-28.6℃条件下对温热环境和空气质量进行了监测。结果表明:犊牛岛采食休息区和运动区的平均气温分别为-1.0℃和-5.2℃,相对湿度分别为89.3%和81.5%,二氧化碳浓度分别为7 324,6 751 mg/m3。说明犊牛岛外围护结构的保温隔热能力仍需加强,通风换气系统仍需进一步完善。     

Effects of long- or short-term exposure to a calf identified as persistently infected with bovine viral diarrhea virus on feedlot performance of freshly weaned, transport-stressed beef heifers

A single experiment with a completely randomized design was conducted to evaluate the effects of long- or short-term exposure to a calf identified as persistently infected with bovine viral diarrhea virus (PI-BVD) on feedlot performance and carcass characteristics of freshly weaned, transport-stressed beef heifers. Two hundred eighty-eight heifers that had been vaccinated for BVD before weaning and transport were processed and given a metaphylactic antibiotic treatment at arrival and were fed common receiving, growing, and finishing diets for a 215-d period. Treatments were designed to directly or adjacently expose the cattle to a PI-BVD heifer. Directly exposed treatments were 1) negative control with no PI-BVD calf exposure (control), 2) PI-BVD calf commingled in the pen for 60 h and then removed (short-term exposure), and 3) PI-BVD calf commingled in the pen for the duration of the study (long-term exposure); and spatially exposed treatments were 1) negative control with no PI-BVD calf exposure (adjacent pen control), 2) PI-BVD calf commingled in the adjacent pen for 60 h and then removed (adjacent pen short-term exposure), and 3) PI-BVD calf commingled in the adjacent pen for the duration of the study (adjacent pen long-term exposure). Exposure to a PI calf transiently (60 h) or for the duration of the feeding period (215 d) did not affect (P > or = 0.25) final BW compared with heifers that were not exposed. Neither period nor overall DMI was affected (P > or = 0.37) by PI-BVD calf exposure, and no differences (P > or = 0.44) were observed between short- and long-term exposed heifers in the direct or spatially exposed groups. Likewise, total trial ADG was not affected (P > or = 0.36) and overall efficiency of gain (P > or = 0.19) was unaffected by PI-BVD calf exposure in the direct or spatially exposed groups. The results from this study suggest that exposing previously vaccinated, freshly weaned, transport- stressed beef calves to a calf that is persistently infected with bovine viral diarrhea virus has little, if any, marked effects on health, performance, or carcass characteristics.     

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.     

The development of injurious pecking in a commercial turkey facility

Injurious pecking is considered a major economic concern and affects all sectors of commercial poultry production. Though extensive research has been performed examining feather pecking in layer chickens, little information exists regarding feather or head pecking behavior in domestic turkey flocks, and less still in commercial settings. The objective of the present field study was to examine the development of injurious feather and head pecking in tom turkeys raised in 2 different commercial environments. At a commercial facility, 49,332 beak-conditioned tom turkeys were placed in 8 barns (5,000–7,500 turkeys/barn) and studied through 16 wk of age. Approximately half were housed in control barns in March 2010; these barns were environmentally controlled (artificial light and tunnel ventilation) in both rearing and growing, with a density of 0.16 m²/bird for rearing through 4.5 wk and 0.39 m²/bird for growing through 16 wk. The remaining turkeys were housed in curtain-sided barns in April 2010; the 4 rearing barns were environmentally controlled with a density of 0.10 m²/bird, whereas the 4 growing barns had natural light and ventilation and a density of 0.36 to 0.38 m²/bird through 16 wk. Two barns from each growing environment were provided with multicolored plastic balls as enrichment. Each housing and enrichment combination had 2 replicate barns. Behavior, weights, and feather condition were assessed every 3 wk. Mortalities and culls were recorded as they occurred. Turkeys in curtain-sided barns had worse feather condition and more culls and mortalities with severe pecking injuries compared with those in control barns. In both environments, severe and gentle pecking was observed throughout production, and the majority of culls and mortalities had severe pecking injuries. More controlled studies are needed to parse the causal factors of injurious pecking in toms.     

Occurrence of MRSA in air and housing environment of pig barns

A high prevalence of MRSA among farm animals, especially pigs, has been observed for some time. However, knowledge on transmission routes of MRSA in livestock production is still scarce. Therefore, the aim of this study was to determine the occurrence of MRSA in pig house air as well as in samples from pigs and their housing environment in 27 MRSA positive pig barns of different sizes and production types. In 85.2% of all barns MRSA was detected in the animal house air. Impingement turned out to be a more sensitive sampling technique than filtration. Other environmental samples such as boot swabs or faeces showed prevalences of MRSA from 55.6% to 85.2% at sample level. The level of MRSA was 88.3% for pooled and 82.1% for single nasal swabs, in skin swabs the one was 87.7%, the others was 78.7%. Spa typing of isolates from air and nasal swabs showed predominantly spa types t011 and t034. MRSA prevalences in pigs as well as in various environmental samples were significantly higher in fattening farms than in breeding farms. This study provides good reference that there could be an airborne transmission of MRSA within pig herds indicating a potential contamination of the environment of barns.     

Association between the existence of calves persistently infected with bovine viral diarrhea virus and commingling on pen morbidity in feedlot cattle

OBJECTIVE: To determine the association between the existence of a calf persistently infected (PI) with bovine viral diarrhea virus (BVDV) and pen morbidity. ANIMALS: 5,041 calves in 50 pens at a feedlot in Iowa. PROCEDURE: In a longitudinal study, ear notches were collected from cattle and tested for BVDV antigen. Characteristics of each pen (owner, sex, disease rate, number of groups, and source) were recorded. The association between the existence of a BVDV-PI calf and morbidity in each pen was examined. RESULTS: Commingling was associated with an increase in respiratory tract disease (odds ratio [OR], 3; 95% confidence interval [CI], 2.5 to 3.6). Ten BVDV-PI calves (10/5,041 [0.2%]) were identified in 8 of 50 pens. A BVDV-PI calf was associated with reduced pen-level respiratory tract disease (OR, 0.7; 95% CI, 0.5 to 0.9). Disease prevalence (mean +/- SD morbidity, 7.9 +/- 3.1%) was lowest in pens containing single-source cattle and a BVDV-PI calf (4 pens containing 302 cattle), compared with single-source cattle with no BVDV-PI calf (mean morbidity, 11.89 +/- 9.7%; 31 pens containing 3,093 cattle), commingled cattle with no BVDV-PI calf (mean morbidity, 29.3 +/- 16.22%; 11 pens containing 1,127 cattle), and commingled cattle with a BVDV-PI calf (mean morbidity, 28.6 +/- 10.1%; 4 pens containing 519 cattle). CONCLUSIONS AND CLINICAL RELEVANCE: Commingling was the greatest risk factor associated with morbidity in each pen. A BVDV-PI calf in a pen was not associated with increased disease prevalence in commingled groups.     

Differences among breed crosses of cattle in the conversion of food energy to calf weight during the preweaning interval

The objective of this study was to determine whether F1 cows that differ in genetic potential for weight at maturity and milk yield vary in the conversion of food energy to calf weight gain. Food intakes and weight change data were recorded by pen for cows and calves from approximately 45 d postpartum. Cows assigned to the study were 7- to 9-yr-old F1s produced by top-crossing Angus, Hereford, Brown Swiss, Chianina, Gelbvieh; Maine Anjou, and Red Poll sires to either Angus or Hereford dams. Calves were sired by Simmentals. Experimental units were pens (10 to 12 cow/calf pairs); pen was replicated within breed of sire in each of 2 yr (n = 24). Calf weight gain and energy consumed by the dams differed among the F1s, as did the ratio of calf weight gain to energy consumed by the calf and cow. Angus or Hereford (35.8), Red Poll (35.7), or Maine Anjou (35.6) F1s produced more calf weight per unit of energy consumed (g/Mcal) by the cow and calf than Chianina (33.1) or Gelbvieh (33.7) F1 females; Brown Swiss cows were intermediate (34.3). Differences in food conversion efficiency exist among breed crosses. These differences seem to be associated with breed cross differences in genetic potential for milk yield and mature weight; an exception to this trend was the Maine Anjou.     

Farm-level risk factors for the presence of Salmonella in 89 Alberta swine-finishing barns

This study investigated potential risk factors for the presence of Salmonella on 89 Alberta swine-finishing farms with the use of a questionnaire. Salmonella status was regressed on each fixed effect in a logistic mixed regression model, with farm as the random effect. Eleven variables were significant at the 10% level: farm type, number of square feet per pen, number of pigs per pen, source of feed, ration type, dust control measures, cat presence, reported effective mouse-control measures, time required to be away from pigs before visiting the farm, precautions taken when entering or leaving the farm, and reported use of antimicrobials through water. Three factors remained significant at the 5% level in the multivariable analysis: farm type, ration type, and precautions taken when entering or leaving the farm. Finishing barns at multisite operations or individual grow-to-finish farms had a greater risk of the presence of Salmonella at a single visit than did finishing barns at farrow-to-finish farms. The use of pelleted and wet feed was associated with higher odds of the presence of Salmonella than was the use of meal feed. Farms that required their personnel or visitors to shower before entering and before leaving had increased odds of the presence of Salmonella compared with farms that provided boots and coveralls; no significant difference was observed between the latter category and farms that used boot disinfection. Further work is necessary to better understand the effectiveness of all-in/all-out pig management and disinfection practices in reducing the presence of Salmonella in swine and to evaluate the association with certain types of feed.     

Incidence of respiratory disorders during housing in non-weaned Charolais calves in cow-calf farms of Pays de la Loire (Western France)

We assessed the incidence rate of respiratory disorders during the 1999–2000 housing period in non-weaned calves reared in a specific cow–calf farming system in western France, examined its variations according to age of the calf, housing facility and meteorological conditions, and described the different time-distribution patterns of incident cases within the barns. Treatments for respiratory disorders were recorded by the farmers on a specific sheet according a written definition provided. A case “occurred” on a given day if the calf concerned was treated for respiratory disorder on this day but not in the previous 14 days. At the barn level, episodes of respiratory disorder were determined based on the time-distribution of incident cases. An episode started on a given day if at least one case occurred on this day in the barn concerned without any cases occurring in the previous 14 days. Data were suitable for analysis for 6813 calves, in 199 barns, located in 137 farms, where no metaphylactic treatment (mass treatment of ill and not-ill calves at the barn level) was implemented. The incidence rate of respiratory disorders was 1.89 cases per 1000 calf-days at-risk. The proportion of reoccurrent cases was 8.6%. During the 1999–2000 housing period, cases occurred more frequently between 1 November and 20 January. The incidence rate of cases peaked between 14 and 20 days of age and was lower after 105 days of age. Large variation in incidence existed among barns. In one-third of the buildings, no case was observed. A higher incidence of cases was observed in loose-housing yards compared to tied-cow stalls. No clear trend between daily meteorological measurements and daily incidence rate of cases was evidenced. A total of 11 barn-level episodes occurred in 9 tied-cow stalls and 229 barn-level episodes occurred in 120 loose-housing yards. Large variations in the characteristics of episodes (duration, incidence of sick calves) and in their time-distribution existed between barns.     

Performance of gestating sows in bedded hoop barns and confinement stalls

The effects of gestation housing systems on sow and litter performance were evaluated for 2.5 yr in southwest Iowa. Gestation housing system treatments were as follows: 1) individual gestation stalls in a mechanically ventilated confinement building with a partially slatted floor and a manure flush system and 2) group pens with individual feed stalls in deep-bedded, naturally ventilated hoop barns. In all, 957 litters from 353 sows were evaluated. Number of pigs born alive per litter differed for the 2 housing treatments (P = 0.002). Sows gestated in hoop barns gave birth to more live pigs per litter (10.0 +/- 0.2 pigs) than sows gestated in stalls (9.3 +/- 0.2 pigs). Preweaning mortality was not different for the 2 housing treatments (P = 0.70). Cross-fostering was done to equalize litter size within 24 h of birth, which resulted in an equal number of weaned pigs per sow (P = 0.50) regardless of gestation housing treatment. The weaning-to-breeding interval was different (P = 0.01), with sows kept in stalls (4.3 +/- 0.6 d) returning to estrus sooner than sows gestated in hoop barns (6.0 +/- 0.6 d). These results indicate that gestating sows can be housed as groups in deep-bedded hoop barns equipped with individual feeding stalls and will perform comparably to gestating sows housed in confinement systems with individual gestation stalls.     

东北地区冬季肉牛采暖舍环境指标测定与评价

[目的]为了解东北地区冬季育肥牛舍的环境状况。[方法]对具有代表性的育肥牛采暖舍进行了为期5d的实地测量试验。所测得的温湿度、风速、CO2浓度、NH3浓度[结果]为:舍内平均温度为12.4℃、湿度为83.9%、风速为0.10m/s、CO2平均浓度为3647ppm、NH3平均浓度为14.7ppm。由测量[结果]可知:采暖舍内温度、湿度和风速均能很好的满足肉牛的生长和育肥的需要。但是CO2、NH3气体浓度稍高,可能是由于通风系统设计不合理造成的,但没有对牛的生长生活产生影响。由此可见,北方冬季采暖舍环境舒适度较高,可作为冬季肉牛舍有效的保温措施之一。[结论]通过本试验的结果,为北方冬季肉牛舍的建筑设计及健康养殖技术的改进提供一定的技术依据。     

Calf morbidity and mortality in smallholder dairy farms in Ada’a Liben district of Oromia,Ethiopia

A longitudinal observational study on calf morbidity and mortality was conducted in smallholder dairy farms in Ada’a Liben district of Oromia, Ethiopia. A total of 185 calves from 112 market oriented smallholder dairy farms were selected randomly and regularly monitored for clinical health problems up to six months of age. Information on potential risk factors was collected by personal observation during the regular visit to farms and from questionnaire survey conducted during the study period. The overall incidences of crude morbidity and crude mortality were 62 % and 22%, respectively. The most frequent disease syndrome was calf diarrhea with the incidence of 39% followed by joint ill 6%. The other disease conditions/syndromes diagnosed include navel ill, pneumonia, septicemic conditions, congenital problems and miscellaneous cases. Age of the calves, age at first colostrum ingestion and cleanness of the calf barns significantly influenced morbidity. Older calves (greater than three months of age) were at lower risk of crude morbidity than younger calves (less than three months of age) (HR = 0.42, P = 0.001). Higher risk of crude morbidity was observed in calves that ingested their first colostrum meal later than 6 hours of age compared to those that ingested colostrum earlier (HR = 2.24, P = 0.001). Similarly, calves housed in unclean barns were at higher risk of morbidity than calves housed in clean barns (HR = 1.75, P = 0.024). Of the 20 potential risk factors investigated, age was the only factor that was found significantly associated with mortality (HR = 0.04, P = 0.001). Calves older than three months of age were at lower risk of mortality than younger calves.     

陕西关中地区肉牛舍内外空气质量时空变化观测分析

[目的]旨在研究不同建筑类型肉牛舍空气中有害气体(NH_3、CO_2、H_2S)、细菌和真菌含量的时空分布变化情况,并分析微生物在舍内外(包括场内和场外)的空间分布规律。[方法]选择陕西省关中地区牛舍为分别为半开放式、开放式和封闭式的3个肉牛养殖场,对其舍内外不同时段的细菌和真菌以及有害气体、温度、湿度等进行同步检测分析。[结果]结果表明,测试期间,三类牛舍的氨气浓度、硫化氢浓度、二氧化碳浓度均在畜禽场环境质量标准允许范围内,而细菌与真菌在部分时间和地点超标,封闭式牛舍的空气质量要明显差于半开放式牛舍与全开放牛舍。[结论]不同建筑类型、不同时间段各牛舍空气质量基本符合国家标准,基本能满足肉牛生长育肥需求,封闭式牛舍需要制定合理的通风换气方案。