Composting characteristics of three bedding materials

Horse manure management is becoming a major concern in suburban areas of the United States. An average horse can produce eight to ten tons of manure per year, accumulating at a rate of two cubic feet per day, including bedding. If properly composted, the manure and bedding can be transformed into a very useful, odorless, pathogenfree product. The objective of this trial was to compare the characteristics of recycled chopped phone book paper, sawdust and wheat straw bedding during composting. Six horses were stalled on three bedding types: recycled phone book paper, sawdust and straw. Each day manure and soiled bedding types were separately collected and transported to compost sites over an eight-day period. Three compositing bins were each hand constructed from wooden pallets with 10 cm slats. The front of the bin was left open for manipulation of materials during the composting process. Initial volumes of the soiled bedding materials were 1m³, 1m³, and 1.5m³ for paper, sawdust and straw, respectively. Temperatures were taken for each bedding materials using a 51 cm REOTEMP compost thermometer. Temperatures were taken on Day 0 and every four days over the 65-day trial (n=52). Temperature was used to determine the need for moisture addition and aerating by turning to keep the piles microbially active. On Day 37 the C:N ratio was adjusted by the addition of ammonium sulfate, 0.1 kg, 0.1 kg and 0.14 kg for sawdust, phone book paper and straw piles, respectively. Mean standard error and range for compost temperatures (C) were: phone book paper, 33.17±10.33 (13–52); sawdust, 45.6±9.35 (27–58); straw, 30.42±6.57 (16–39). The sawdust composted more readily as compared to the phone book paper or straw. The paper and straw had poorer structure, which caused compaction of the material when moistened; thus, porosity, oxygen supply and microbial activity were reduced.     

Effects of Bedding Material on the Lying Behavior in Stabled Horses

The objective of this study was to investigate the effect of straw, sawdust, coconut husk (husk), and coconut fiber (fiber) on the welfare of stable horses by observing their resting behavior. Twenty horses with ages ranging from 3 to 21 years were used at the Equine Research Institute of the Japan Racing Association, Utsunomiya, Japan. Five horses were allocated to each bedding condition. The behavior of each horse was recorded by video camera for 3 days and was continuously sampled from 17:00 to 05:00. The total duration, the number of bouts, and the mean and the maximum duration of bouts in standing rest, sternal lying, and lateral lying were calculated and analysed by the Kruskal-Wallis test and post hoc Steel-Dwass test. There was no difference in the standing rest and the sternal lying among beddings. Significant differences were observed in these values in the lateral lying among the different beddings (P<0.05). The values of the means of the total duration, the number of bouts, and the mean and the maximum duration of bout in the lateral lying were greater when husk was used as the bedding material than when sawdust were used (P<0.05). The results of the observations show that the new bedding materials would be as usable as straw. However, lateral lying was observed less frequently when sawdust were used as bedding; this indicates that use of sawdust as bedding material will decrease the welfare of stabled horses.     

Measurement of ammonia concentrations in horse stalls

The effect of treating stall floors with an ammonia-absorbingcompound (AAC) on aerial ammonia levels was tested during two 14-day periods in a four-stall barn. In the first period, two stalls were treated with the AAC and the other two stalls remained as the non-treated controls. In the second period, the stalls were switched. Four geldings were used in each period and were randomly assigned to the stalls. The horses remained in the stalls at all times except for 30 min of turn-out per day at which time the stalls were cleaned. Ammonia levels at the stall floor were measured by a Bruel and Kjacr 1302 gas monitor on day 0 before the horses were admitted to the barn and on days 1, 3, 5, 7, 10 and 14. Ammonia diffusion tubes were attached to the horses' halters on days 1, 7, 11 and 13 for 8 hours to determine the level of ammonia exposed to the horse. On day 14, ammonia concentrations near the stall floor were 25% lower in treated stalls than in control stalls (P<0.1). Ammonia concentrations measured at the halter were much lower than those at the floor, but horses in treated stalls had lower ammonia exposure than horses in control stalls (P<0.1).     

Water Absorption Capacity of Flax and Pine Horse Beddings and Gaseous Concentrations in Bedded Stalls

It can be a challenge to find suitable horse bedding materials that provide higher moisture absorption, better animal comfort, greater fertilizer values, and improved indoor environment. Our first objective was to determine the water absorption capacity (WAC) of two bedding materials, flax shive (FS) and pine wood shavings (PWS), commonly used by equine facilities. The second objective was to measure ammonia (NH₃), hydrogen sulfide (H₂S), and greenhouse gas (GHG) concentrations emitted from these bedded stall surfaces. In this study, the WAC of bedding materials were measured at 0.5, 1, 2, 3, 4, 6, 8, 12, and 24 hours in the laboratory. A total of eight horses were used for a 14-day study period. Of these, four horses (group-1) were bedded with FS and the other four (group-2) were bedded with PWS for week-1. In week-2, bedding materials were switched between the two groups. Ammonia and H₂S were measured in situ. For GHG measurement, air samples (methane [CH₄], carbon dioxide [CO₂], and nitrous oxide [N₂O]) were collected 152 mm above the bedded stall surface in Tedlar bags using a vacuum chamber and analyzed for GHG using a gas chromatograph. The WAC of FS was 56% greater than the PWS. There were no significant differences in NH₃, H₂S, CH₄, CO₂, and N₂O concentrations between the two bedding materials (P > .05). Nutrient contents between fresh and soiled bedded samples for each bedding type were different (P < .05). Measured nutrient contents between fresh FS and PWS and bedded FS and PWS bedding materials were similar (P > .05).     

Chemical, physical, and environmental properties of pelleted newspaper compared to wheat straw and wood shavings as bedding for horses.

Two experiments were conducted comparing pelleted recycled newspaper (PN) to wheat straw (S) and kiln-dried pine wood shavings (WS) as an animal bedding material. Adult horses housed 20 to 21 h/d in boxstalls served as the animal model for comparisons. In Exp. 1 eight boxstalls, each housing one horse, were each bedded with two types of PN (0.32 and 0.64 x 2.54 cm), S, and WS over four 5-d periods (replicated 4 x 4 Latin square). Initial amounts of bedding materials surpassed most commercial conditions, but stalls were cleaned daily of feces only and additional clean bedding was added as needed to maintain animal cleanliness, thus challenging the bedding properties of each material. In Exp. 2 nine boxstalls were bedded with PN (0.32 x 2.54 cm), S, and WS over three 14-d periods (three 3 x 3 Latin squares) during summer and autumn. Feces and wet spots were removed daily and clean bedding was added to reestablish working volume and simulate commercial conditions. In Exp. 1 and 2 daily additions of clean bedding varied (P < 0.05) with material (S > WS > PN). The higher water-holding capacity of PN and WS contributed to fewer bedding replacements. Usage of each material was greater (P < 0.05) during the autumn; PN had the greatest increase. Type of material and season also influenced bedding environment. Bedding pH increased (P < 0.05) with use and was highest in PN and lowest in S. Higher concentrations of breathable NH3 N were present in stalls bedded with PN and during autumn. Higher pH of used PN and decreased ventilation due to closed doors and windows during autumn were contributing factors. Season, type of bedding, and duration of its use affected (P < 0.05) numbers as well as species of microorganisms present in the breathing zone, nasal cavity, and on the leg of the horse. Clean and used WS contained greater (P < 0.05) quantities of particle fines, but with 5 d of use, particle fines in PN also increased. Quantities of breathable dust during cleaning of stalls varied (P < 0.05) with material and duration of its use; dust peaked at d 7 with PN but continued to decrease with S and to increase with WS through d 14. These data indicate that management of bedding materials varies with type of material and season of year. Use of PN as a bedding material has high potential.     

Horse hair coat cleanliness is affected by bedding material: A comparison of clean and used wheat straw, wood shavings and pelleted newspaper

Wheat straw, wood shavings and pelleted recycled newspaper were used as bedding materials and compared in maintaining horse hair coat cleanliness. Each material was sampled prior to use and after use having been wetted with urine in a bedding study conducted with 4 adult horses in box stalls. Because feces were removed daily during stall maintenance, frehhly voided feces were also collected so that all components in a used bedding (clean portion, wetted portion, feces) were represented. Hair coat cleanli-ness was measured in vitro by exposing a tanned pony hide with hair to clean and wet beddings as well as feces. Cleanliness was evaluated in terms of the amounts of moisture, volatile-N and solid matter transferred from each component and type of bedding material to the haired hide. Transfers to wool flannel were also measured as a comparison to the haired hide. Woolen products are used in the horse industry and also come into contact with components of used bedding. Freshly voided feces and used beddings transferred more (P<.05) moisture (85 and 54%, respectively) than clean beddings. Wheat straw transferred less (P<.05) solid matter (86 and 64%, respectively) than wood shavings or pelleted newspaper. Wood shavings transferred more (P<.05) solid matter than wheat straw or pelleted newspaper to wool flannel resulting in a statistically significant used bedding X surface interaction. These data indicate that type as well as components of used beddings affect hair coat cleanliness. The ability of a bedding material to maintain hair coat cleanliness should also be a factor (e.g., cost, availability, moisture holding capacity, nontoxicity) in its consideration for use as a bedding for animals.     

Investigating duration of nocturnal ingestive and sleep behaviors of horses bedded on straw versus shavings

Horses are stabled overnight for a number of practical reasons; however, there is little research quantifying nocturnal equine behavioral patterns or the extent to which different environments influence nocturnal behavior. The aim of this study was to establish whether differences in duration of sleep and ingestive behaviors were apparent for horses bedded on straw (group 1) or shavings (group 2). Ten geldings of mixed breed (mean age: 7.3 ± 3.53 years) bedded on either shavings (n = 5) or straw (n = 5) were observed between 7 pm and 7 am. Duration of behaviors according to a predefined ethogram was recorded in minutes using a video recorder and continuous focal sampling. Mann–Whitney U tests were used to identify whether any significant differences in duration of ingestion and sleep behaviors occurred for horses bedded on straw compared with shavings. Of the total observation period, group 1 spent, on average, 29.3% of their time budget engaged in recumbent behaviors, compared with 12.2% for group 2. However, no significant differences in duration were established between horses bedded on straw or shavings for standing sleep, sternal recumbency, and lateral recumbency behaviors (P > 0.05). Ingestive behaviors occupied approximately one-third of the time budget, with no significant difference (P > 0.05) observed between groups. On average, group 1 spent a longer proportion of the observation period ingesting bedding (8.1%) compared with group 2 (1%). Duration of bedding ingestion appeared to peak between 1 am and 7 am for both groups. Although not quantified, general observations revealed horses were motivated to alternate between eating hay and bedding in both groups, owing to the prevalence of bedding ingestion. The results indicate that straw bedding facilitates the display of ingestive and sleep behaviors, whereas horses bedded on shavings spent a greater proportion of their nocturnal time budget engaged in “other” behaviors. Further research is required to investigate the extent to which different types of bedding material enrich the environment of horses that are stabled overnight.     

Cytologic examination of specimens obtained by means of tracheal washes performed before and after high-speed treadmill exercise in horses with a history of poor performance

OBJECTIVE: To evaluate results of cytologic examination of specimens obtained by means of tracheal washes (TW) in 42 horses with a history of poor performance. DESIGN: Cross-sectional case series. ANIMALS: 42 horses with a history of poor performance. PROCEDURE: A TW was performed via endoscopy before and after horses exercised on a high-speed treadmill, and specimens were evaluated microscopically and graded. RESULTS: Ten (24%) horses were considered to be clinically normal before and after exercise. Pulmonary hemorrhage was diagnosed in 8 (19%) horses. One horse had evidence of exercise-induced pulmonary hemorrhage (EIPH) before exercise and pulmonary hemorrhage and allergic or inflammatory airway disease (IAD) after exercise. Five (12%) horses had IAD, and 1 had IAD and pulmonary hemorrhage after exercise. Seven (17%) horses had evidence of EIPH and IAD in both specimens. Four (10%) horses with EIPH had an increase in the proportion of hemosiderophages in the specimen obtained after exercise. Specimens obtained before exercise in 6 (14%) horses were not representative of the respiratory tract and could not be compared with specimens obtained after exercise. CLINICAL IMPLICATIONS: Interpretation of TW specimens obtained before and after exercise differed for only 5 of 36 (14%) horses. Specimens obtained after exercise were more likely to reveal airway disease. All specimens obtained after exercise adequately represented the respiratory tract, whereas 6 specimens obtained before exercise did not. Specimens obtained after exercise contained more airway secretions and had less cytologic evidence of pharyngeal contamination. Therefore, we recommend that TW samples be obtained after exercise in horses.     

Relationship of equine housing to large airway inflammation

The pasture, as compared to stall confinement, has been considered a more desirable environment for maintaining the health of the respiratory system in the horse. This conclusion is based on reports which showed that ventilation in most barns was generally poor, and that horses bedded on straw and fed hay were exposed to many forms of respirable debris. In this study, six normal horses were evaluated for evidence of airway mucosal inflammation after being housed on pasture or stabled in a barn for one month. The response of the horses' airways was measured by assigning scores for the degree of tracheal mucosal secretions that were observed by endoscopic visualization. Cytological examination of transtracheal wash secretions was also performed, as well as histologic evaluation of tracheobronchial tissues obtained by a transendoscopic epithelial biopsy technique. Samples were collected at three time points; the initial collection occurred after the horses were housed on pasture for one month. The horses were subsequently moved to a barn for an equal length of time and samples were obtained at the end of this period. The horses were then returned to their original pasture and final sampling was performed after they were housed in this environment for two months. There were no significant changes in any of the parameters evaluated, regardless of the environment in which the horses were maintained. These findings indicate that housing horses in a barn for four weeks does not cause tracheobronchial mucosal inflammation in a manner that could be detected using the methods employed in this study.     

Stabling causes a significant increase in the pH of the equine airway

Regulation of pH homeostasis in the equine lung is poorly understood. Measurement of exhaled breath condensate (EBC) pH provided a simple, highly repeatable and noninvasive method for the longitudinal investigation of changes in airway pH in response to environmental changes. Stabling of horses was found to lead to a small (approximately 100–200 parts/ billion) but significant (P<0.001) increase in ambient ammonia concentration when compared to pasture. This increase in exposure to ambient ammonia concentration was associated with significant (P = 0.002) increases in EBC pH and exhaled ammonia (P = 0.013). Stable feed/bedding management type had no effect on EBC pH or exhaled ammonia concentration, while ambient ammonia concentration was influenced by stable management type.     

Suitability of biocompost as a bedding material for stabled horses: respiratory hygiene and management practicalities

REASONS FOR PERFORMING STUDY: Bedding material in stables has an important influence on air hygiene and information on the suitability of biocompost and wood shavings is incomplete. OBJECTIVES: To compare the suitability and benefit of biocompost and wood shavings as bedding in horse stables and to determine key air factors for the evaluation of the potential impact of these materials on respiratory health. METHODS: The study was conducted in a naturally ventilated stable with 4 horses. Air hygiene parameters were measured 24 h/day for 7 days with each bedding type: ammonia (NH3), inhalable and respirable dust, endotoxins, colony forming units (CFU) of total mesophilic bacteria, fungi, actinomycetes and thermophilic actinomycetes. Both bedding materials were analysed for general chemical composition, particle size distribution and natural microbial content. The animals' behaviour was monitored by video cameras, and their health and cleanliness status determined by clinical and visual examination. RESULTS: Concentrations of NH3, dust, endoxins and fungi were significantly higher during the monitoring period with wood shavings than with biocompost. In contrast concentrations of mesophilic bacteria, mesophilic actinomycetes and thermophilic actinomycetes microbial pollutants were highest with biocompost. The water content of bulk biocompost was considerably higher than that of wood shavings. Particles < or = 0.4 mm were not detectable in bulk wood shavings. The concentration of thermophilic actinomycetes by weight in raw biocompost was 639 times higher than in raw wood shavings. No significant differences were observed in the time spent by the horses lying down. The biocompost material tended to adhere more intensively to the animals' hair coat. Horses showed no clinical signs indicating any adverse effects of the biocompost material during the trials. CONCLUSIONS: Biocompost cannot be recommended as bedding material for horses in stables, because the concentration of thermophilic actinomycetes and other agents that elicit and maintain recurrent airway obstructions was significantly higher with biocompost than with wood shavings. To ensure the well-being of horses, any new bedding material must be tested very carefully before it is introduced to the market.     

Mastitis in a large, zero-grazed dairy herd

A zero-grazed herd of approximately 400 cows had a significant mastitis problem associated with Escherichia coli and Streptococcus uberis during a study over three and a half years. Dry cow therapy and post-milk teat dipping effectively controlled staphylococci and the bulk milk cell count averaged less than 400 X 10(3) cells/ml, but over 1800 clinical cases of mastitis occurred over this period, 32 per cent of which were associated with E coli and 25 per cent with Str uberis. Only 8 per cent of the cases associated with E coli showed obvious systemic disturbance and 75 per cent were cured following penicillin and streptomycin treatment. The incidence was highest during spring and summer when the housed cows were dirtiest. Gross teat-end contamination came mainly from sources other than cubicle bedding, and changing the bedding from sawdust to sand did not alter the incidence of clinical mastitis. It was not possible to maintain adequate cleanliness either inside or outside the parlour, nor maintain a trouble-free milking apparatus. The costs of mastitis in this herd during one year are calculated.     

不同卧床材料对海福特母牛舒适度、繁殖及健康状况的影响

[目的] 为了研究不同卧床材料对海福特母牛舒适度、繁殖及健康状况的影响。[方法] 将600头海福特母牛随机分为 4 组,每组150头,分别散放饲养于混凝土地面、砖铺地面、木屑垫料、细沙子卧床,测定微生物数量,观察母牛舒适度、受胎率、健康状况;[结果] 结果表明,细沙子和砖铺地面的霉菌显著低于混凝土地面和木屑垫料(P<0.05);细沙子中的金黄色葡萄球菌数量极显著低于混凝土地面和木屑垫料(P<0.01);细沙子中的大肠杆菌数量最少,显著低于混凝土地面、砖铺地面和木屑垫料(P<0.05)。细沙子和木屑垫料能显著提高海福特母牛躺卧率(86%和90%,P<0.05),显著高于混凝土地面和砖铺地面;使用细沙子和木屑垫料比混凝土地面和砖铺地面显著降低了海福特牛肢蹄病发病率(14%和5%,P<0.05)。细沙子垫料与混凝土地面、砖铺地面、木屑垫料相比较,显著提高了海福特母牛受胎率和犊牛成活率(92%、98%,P<0.05)。[结论]细沙子垫料与混凝土地面、砖铺地面、木屑垫料相比较,显著降低了霉菌、金黄色葡萄菌和大肠杆菌的数量,提高了海福特母牛躺卧率、受胎率和犊牛成活率,降低了肢蹄病发病率。     

Some preliminary observations on the possible relationship between ammonia production from soiled bedding in calf rearing sheds and calf illness

A limited field study of covered facilities used for raising dairy calves suggested that respiratory disorders and death rates were highest when calves were continuously housed on bedding composed of wood shavings, where ventilation was poor and where automatic feeders were installed. High concentrations of ammonia were found in the urine-soaked bedding following overnight incubation. A prolific growth of mixed micro-organisms isolated from the shavings rapidly colonised plates of selective urea medium. Death rates of 10% and 13.5% were observed on two properties. Respiratory distress was common and lung disease was intractable to treatment on these farms. A histopathological diagnosis of subacute purulent pneumonia with distal necrotising bronchiolitis was made, similar to lung lesions produced experimentally in cats, guinea pigs and rabbits exposed to ammonia gas.     

Influence of Equine Conformation on Rider Oscillation and Evaluation of Horses for Therapeutic Riding

To obtain basic knowledge about selecting horses for therapeutic riding, the influence of equine conformation on rider oscillation and relationships between these factors and the evaluation on horses as the therapeutic riding were studied. Thirty-five riding horses were used. Equine conformation was estimated by 24 indices. Rider oscillation was measured by an accelerometer fixed at the rider’s waist. The spatial position of the oscillation was estimated by a double integration of the acceleration. Horses were evaluated for therapeutic riding by a Riding for the Disabled Association instructor as a rider. Evaluations were on a scale of 1 to 5, with 5 being the highest score for 27 items. Horses were classified into 4 groups: the short and narrow (SN), short and wide (SW), tall and narrow (TN), and tall and wide (TW). The frequencies of rider oscillation both at walk and trot were higher (P<0.01), and the vertical (P<0.01) and longitudinal (P<0.05) amplitudes at trot were smaller, on short horses than on tall horses. The vertical amplitude at walk was smaller (P<0.05) and the lateral amplitude at trot was larger (P<0.01) on wide horses than on narrow horses. Short horses could be used for the rider who requires side walkers. Wide horses could be used for relieving muscular tension and for the rider who could not maintain good balance on the horse. Short and wide horses should be suitable for therapeutic riding.     

Quality of different bedding materials and their influence on the compostability of horse manure

The air quality of the stable and management and composting of manure can be improved by choosing bedding material with certain desirable properties. The optimal bedding material doesn't cause hygiene problems in the stable. It absorbs ammonia, is economic in use, and decomposes quickly with manure. The objective of this trial was to compare both quality of different bedding materials and their influence on the composting process of horse manure. Bedding materials used in the study were wood chips, straw, peat, hemp, linen, sawdust, shredded newspaper and the mixtures, peat/wood chips, peat/sawdust, and peat/straw. Peat and peat mixtures had the best quality of ammonia absorption, water holding, and manure fertilization value. The number of fungi and bacteria were lower in shredded newspaper and wooden materials than in straw, linen, hemp, and peat. The composting temperature became high enough for at least a partial destruction of parasites and seeds within the rubbish heaps in all boxes. Only peat manure was ready for further plant production after one month's composting period. Other bedding materials were decomposed only partially or not at all during the study.     

Bedding hygiene,cleanliness and lying behaviour for heifers housed on wood chip or straw deep bedding

The aim of this project was to compare the hygienic quality of the bedding, as well as the parasitic load, cleanliness and lying behaviour in heifers kept on either straw or wood chip deep bedding. Fourteen heifers kept in two pens were housed on straw or wood chip bedding for 43 days, after which the bedding material was switched for 43 additional days. Significantly more mould was found in wood chip than in straw and there was a tendency towards less yeast in wood chip. The heifers had a low faecal parasitic load. The results indicate that the wood chip treatment resulted in somewhat cleaner animals. The heifers had a significantly longer total lying time when kept on straw. In conclusion, wood chip deep bedding could be an option as bedding material, but the impact on hygiene of bedding material and lying behaviour needs to be further investigated.     

Evaluation of clinical signs of disease, bronchoalveolar and tracheal wash analysis, and arterial blood gas tensions in 13 horses with chronic obstructive pulmonary disease treated with prednisone, methyl sulfonmethane, and clenbuterol hydrochloride.

We evaluated the efficacy of 3 treatments for chronic obstructive pulmonary disease in horses: prednisone (400 mg/horse, PO, daily; n = 7), methyl sulfonmethane (10 g/horse, PO, q 12 h; n = 6), and clenbuterol hydrochloride (0.4 mg/horse, PO, q 12 h; n = 7). A fourth group acted as controls (n = 6) and was not treated. The treatment period lasted 10 days. Each horse was a member of 2 different groups for 10 days, separated by an 18-day interval of no treatment. All horses were housed together in an outdoor pen without bedding. Horses were fed alfalfa/grass hay mix ad libitum from a large feeder. The same batch of hay was fed throughout the study. Multiple physical and laboratory variables were monitored prior to, during, and at the end of each 10-day trial period. Changes in lung sounds, respiratory effort, degree of anal movement, nasal discharge, temperature, respiratory rate, or heart rate were not significant. Changes in arterial blood gas tensions, tracheal wash or bronchoalveolar lavage cytologic findings, or phagocyte function were not significant. All horses were tachypneic and most were tachycardic. The median value for PaO2 was below normal for all horses. All tracheal wash and most bronchoalveolar lavage cytologic findings represented a suppurative response. Negative linear correlation was observed between PaO2 and degree of respiratory effort in these horses (eg, as PaO2 decreased, the degree of respiratory effort increased).     

Area of hock hair loss in dairy cows: Risk factors and correlation with a categorical scale

Data from 3691 dairy cows from 76 farms were used to investigate the risk factors associated with the area of hair loss over the lateral aspect of the hock and the correlation between the area of hair loss (as calculated using a hock map) and hock lesion scores determined using a pre-existing categorical scale. Six factors were associated with a greater area of hair loss, including cows with locomotion score 3, a cleanliness score (10/28 to 18/28), high daily milk yield (25.1–58.1 kg), poor body condition score (1–1.5), duration of winter housing (≥41 days) and some combinations of cubicle base and bedding materials.Compared with cows housed in cubicles with a concrete base and whole straw or rape straw bedding, cows housed in cubicles with concrete bases with sand or chopped straw bedding had smaller areas of hair loss and cows housed on a mattress base with whole straw or rape straw bedding had larger areas of hair loss. Area of hair loss, as measured on hock maps, was not significantly different between cows with score 1 (median 23.6 cm²) and score 2 (median 20.3 cm²) on the categorical scale for hock lesions. This suggests that the categorical scale was not reflecting the extent of hair loss and that hock maps are a good alternative for studying the dynamics of hock lesions over time.     

Factors affecting the circadian rhythm in plasma cortisol concentrations in the horse

In horses, a circadian rhythm in plasma cortisol concentrations has been reported in some but not all studies. When a rhythm occurred, horses were accustomed to a management routine, comprising stabling, feeding and sometimes exercise, which may entrain a circadian pattern. In this work, we monitored plasma cortisol by collecting jugular blood through indwelling cannulae from four groups: 1): 10 untrained, unperturbed mares grazing excess pasture, bled hourly for 26 hr; 2) 4 mares housed in a barn for 48 hr before sampling every 15 min for 20–24 hr; 3) 5 mares placed in an outdoor yard for sampling every 30 min from 0930–2100 hr; and 4) 4 stabled racehorses in training, bled every 30 min from 0730–2000 hr and once the following morning at 0830 hr.Plasma cortisol showed a similarly-timed circadian rhythm (P<0.0001) in all Group 1 horses, with a peak at 0600–0900 hr, and a nadir at 1800–2100 hr. By contrast, cortisol concentrations did not vary with time in either Group 2 or 3. Neither daily mean nor peak cortisol values differed in Group 1 and 2 (i.e. bled for ≥ 20 hr); however nadir values were higher (P<0.05) in Group 2. In Group 4, cortisol declined (P=0.004) during the sampling period but had returned to initial concentrations the next morning. Values did not differ from those for Group 1, except between 1000 and 1300 hr when cortisol in Group 4 was lower (P<0.05).We conclude that a circadian cortisol rhythm exists in horses in the absence of any known cues imposed by humans. However, this rhythm can be obliterated by the minor perturbation of removing the horse from its accustomed environment. By contrast, the rhythm occurs in trained racehorses, suggesting either that they have adapted to their environment thereby allowing an endogenous rhythm to emerge, or that the rhythm is entrained by their daily routine. These observations highlight the difficulties in determining the cortisol status of a horse, since measurements will be affected by time of day, the occurrence of short-term fluctuations, and how accustomed the horse is to its environment.