Effect of refined soy oil or whole soybeans on intake, methane output, and performance of young bulls

An experiment was conducted to establish the effects of feeding refined soy oil (RSO) or whole soybeans (WSB) containing soy oil on DMI, animal performance, and enteric methane (CH4) emissions in young bulls. Thirty-six Charolais and Limousin cross-bred, young beef bulls (338 +/- 27 kg of BW, 218 +/- 17 d of age at the beginning of the experiment) were blocked by BW, age, and breed before being assigned in a randomized complete block design to 1 of 3 experimental treatments (n = 12). The experimental period lasted for 103 d, with enteric CH4 output recorded for 2 periods of 5 consecutive days on d 37 to 41 and d 79 to 83. The 3 dietary treatments consisted of a barley/soybean meal-based concentrate with 0 g/d of RSO; oil from WSB as 6% of DMI (WSB treatment); and oil from RSO as 6% of DMI (RSO treatment). Each diet had a 10:90 forage:concentrate ratio, using barley straw as the forage source. Diet affected DMI (P < or = 0.001) and GE intake (P < 0.05 during the CH4 measurement periods), with the WSB treatment producing the lowest values. The addition of WSB decreased ADG (P < 0.05) compared with the RSO treatment. The WSB treatment also decreased (P < 0.05) average daily carcass gain (ADCG). Both the RSO and WSB concentrates decreased (P < 0.05 to P < 0.001) daily enteric CH4 output when expressed in terms of liters per day, liters per kilogram of DMI, percentage of GE intake, liters per kilogram of ADG, and liters per kilogram of ADCG. Diet had no effect (P = 0.557) on ruminal protozoal numbers. The reductions in enteric CH4 were achieved at relatively high oil inclusion levels. Such oil levels have previously been reported to decrease DMI of high-forage diets, although no effect on DMI was noted with the low-forage diets fed in this experiment. This impact on DMI of high-forage diets may limit the range of diets for which this CH4 reduction strategy may be applicable. The inclusion level of WSB in the current experiment (27%) was beyond the palatability threshold of the bulls used and resulted in a marked decline in intake and performance. Therefore, WSB may have a role to play in ruminant diets, but only at a reduced inclusion rate.     

The use of megavoltage radiation therapy in the treatment of thymomas in rabbits: 19 cases

An overall median survival time (MST) and prognostic factors in rabbits with thymomas treated with megavoltage radiation therapy (RT) were determined in this multi-institutional retrospective case analysis. Medical records for 19 rabbits with suspected or confirmed thymomas treated with RT were evaluated for data including signalment, haematological and serum biochemistry abnormalities, presence of pleural effusion, radiation plan, body weight, total radiation dose and institution administering RT. Statistical significance of these factors related to overall survival was assessed. An overall MST for all 19 rabbits was 313 days; exclusion of 3 rabbits that died acutely during the first 14 days of RT yielded a MST of 727 days. The only factor associated with a significantly decreased survival time was having a body weight lower than mean body weight of 1.57 kg. Radiation treatment-associated complications were infrequent and included radiation-induced myocardial failure, radiation pneumonitis and alopecia.     

A survey of feeding,management and faecal pH of Thoroughbred racehorses in the North Island of New Zealand

AIM: To identify feeding and management variables associated with variation in faecal pH within a population of intensively managed Thoroughbred racehorses in New Zealand.

METHODS: A cross-sectional survey was conducted of 16 racehorse trainers in the North Island of New Zealand. Interviews were conducted at the trainers' stables to obtain information on feeding and management of horses, and faecal samples were collected and faecal pH measured.

RESULTS: Ninety-seven percent of the horses surveyed were confined in an area ≤5 × 5 m for ≥12 h/day. Trainer's age, number of years they had trained horses, age and gender of horses, weeks in race training, racing class, frequency of feeding, bedding type, and exercise workload had no effect on mean faecal pH. Acidic faecal pH (pH ≤6.32) was associated with stables with ≤12 horses, and trainers at stables with ≤12 horses offered more concentrate feed than those at stables with >12 horses. Acidic faecal pH was associated with trainers who offered 4 kg of grain as the only form of concentrate fed, or offered ≤2.25 kg hay/day. Horses that displayed stable vices had less acidic faecal pH than horses that did not display stable vices, viz pH 6.70 (standard error of the mean (SEM) 0.135) vs 6.43 (SEM 0.029) (p=0.04).

CONCLUSIONS AND CLINICAL RELEVANCE: Racehorse management in New Zealand is similar to that observed in other major racing countries. Trainers with ≤12 horses fed more concentrates and their horses had lower faecal pH than those of trainers with >12 horses. Irrespective of management system, it appears important to provide at least 2.25 kg of hay/day ad libitum, to buffer hindgut acidosis associated with diets high in soluble carbohydrate.     

Musculoskeletal responses of 2-year-old Thoroughbred horses to early training. 8. Quantitative back-scattered electron scanning electron microscopy and confocal fluorescence microscopy of the epiphysis of the third metacarpal bone

AIM: To characterise and explain the increase in density evident by computerised tomography (CT) and radiography in companion studies as a response to training, in bone in the palmar and dorsal regions of the condyles of the third metacarpal bone (Mc3) of 2-year-old Thoroughbred horses.

METHODS: Compositional back-scattered electron (BSE) imaging in scanning electron microscopy (SEM) and confocal scanning laser microscopy (CSLM) were conducted on polymethyl methacrylate (PMMA)-embedded mediolateral slices of the right distal Mc3 from seven 2-year-old Thoroughbred horses trained on a racetrack and seven untrained horses kept at pasture. One left Mc3 from each group was studied in transverse section planes. This study focussed on regions of Mc3 found to differ in density between the trained and untrained horses in companion studies using CT and radiography.

RESULTS: The increase of bone density in the condyles of Mc3 in trained horses compared with untrained horses occurred, without prior osteoclastic resorption, via the deposition of new bone on pre-existing internal surfaces. Within prior marrow spaces of cancellous bone, there was also rapid formation of immature strands and fronds of bone which were more cellular and mineralised, and more lamellar bone tissue was deposited on these new scaffolding elements in the trained horses. Both resulted in increased bone volume fraction (BVF). The microscopic mineralisation density of the bulk of the new tissue was lower than in pre-existing bone, and CT and radiography underestimated the increase in BVF. The new tissue was thus probably less stiff at the microscopic scale than pre-existing bone, though its addition would stiffen the global structure.

CONCLUSIONS: In Mc3 of all the trained horses, there were obvious differences in microscopic structure compared with those from the untrained horses. Moderate, industry-standard levels of exercise used to prepare young horses for racing induced the formation of new bone in non-bone spaces in bone tissue, such that the bone organ should better withstand later increased levels of exercise.     

Musculoskeletal responses of 2-year-old Thoroughbred horses to early training. 1. Study design,and clinical,nutritional, radiological and histological observations

AIMS: This is the first in a series of papers reporting studies in 2-year-old Thoroughbred racehorses that aimed to determine the response of musculoskeletal tissues to early training on grass and sand racetracks. In this paper, the experimental set-up of the whole study is described, and nutritional, workload, and clinical, radiographic and pathological outcomes are reported, including semi-quantitative assessment of macroscopic changes in articular cartilage.

METHODS: The study group comprised 14 two-year-old Thoroughbred fillies reared entirely at pasture. Of these, seven were selected by a licensed racehorse trainer to undergo a 4-week period of initial training in which they were taught to accept saddle and rider, followed by a 13-week period of flatrace training at a racetrack (Weeks 1–13); the other seven fillies were confined to large grass enclosures and were not trained. Nutrient, including macro- and trace-element intakes were estimated. Distances cantered or galloped and average velocities were quantified for the trained horses. All horses were observed daily, weighed approximately weekly, and underwent a clinical lameness examination at Weeks 5, 9 and 13. Distal forelimbs were radiographed prior to Week 1, during Weeks 7–8, and again at the end of the study, when macroscopic changes in articular cartilage of the proximal surface of the proximal phalanx were also scored after staining with India ink.

RESULTS: Dietary intakes met or exceeded recommended requirements for all nutrients except sodium, which was low in the trained horses. Bodyweight increased throughout the study in the untrained horses, and increased until Week 7 and then decreased slightly in the trained horses. Mean velocity data were used to define three stages of the training programme: Stage 1 comprised canter in Weeks 1–4; Stage 2 comprised canter in Weeks 5–8; and Stage 3 comprised canter in Weeks 9–13 and galloping twice weekly. Four of seven horses completed training. These covered a mean distance of 179.2 km at mean velocities (excluding gallops) of 7.63 m/sec (SD 0.58), 8.99 m/sec (SD 0.56), and 8.43 m/sec (SD 0.74) for Stages 1–3, respectively, and galloped 4.45 km at 14.4 (SD 0.1) m/sec. The three horses that did not complete training became lame in Weeks 9, 10 and 11, and covered 147.9 km at velocities of 7.38 m/sec (SD 0.44), 8.88 m/sec (SD 0.33) and 8.43 m/sec (SD 0.59) and galloped 2.1 km. Overall, slight or intermittent lameness in trained horses was noted on 76/655 (12%) of horse observation days. Swelling was evident on 284/655 (41%) of horse observation days in the metacarpophalangeal (MCPJ) and metatarsophalangeal (MTPJ) joints (92%), palmar metacarpal tendon region (7%) or carpus (1%). Swelling of the MCPJ or MTPJ was not associated with obvious lameness. Radiographic changes were minor and no gross lesions in bone or tendon tissue were evident except for one case of dorsal metacarpal disease. Post mortem, the cartilage of some MCPJ and MTPJ had obvious wear lines and high lesion scores, which were not consistently related to clinical evidence of pain, lameness or joint swelling. Mean lesion scores were not significantly different between the MCPJ and MTPJ, or between trained and untrained horses.

CONCLUSIONS: Workload can be readily quantified in racehorses under semi-commercial training conditions. Obvious lesions in cartilage of the MCPJ or MTPJ were present in some trained and some untrained horses and not consistently associated with clinical evidence of lameness, joint swelling or change in other connective tissues.

CLINICAL RELEVANCE: Workload data in racing horses are likely to be highly relevant for studying the pathogenesis of changes in bone, tendon and cartilage during training, for training management and for risk analysis in racehorse populations. Although obvious cartilage lesions produced little clinical effect, such lesions have previously been shown to be progressive and to prejudice athletic capability. Detection of such occult lesions in young horses will require more sophisticated detection methods.     

Evaluation of Nitric Acid Extraction of Elements from Soils and Sediments in Two watersheds in East Tennessee

Determining the total elemental concentrations of soils requires a total dissolution method, in which hydrofluoric acid (HF) is commonly used. However, this method is tedious and risky due to the dangerous reagent HF. This study compared a single acid extraction technique using a nitric acid (HNO₃) extraction method to total dissolution (HF + microwave assisted aqua regia) for evaluating the total elemental concentrations in soils and sediments. The two methods were used to analyze the elemental content of soils and sediments from the Oostanaula Creek and Pond Creek watersheds in East Tennessee. Twenty-one elements (Al, Ba, Ca, Co, Cr, Cu, Fe, K, La, Li, Mg, Mn, Nd, P, S, Si, Sr, Ti, V, Zn, and Zr) were subsequently measured using inductively coupled plasma optical emission spectrometry (ICP-OES). The extraction efficiency for HNO₃ relative to the total was compared and discussed. In general, HNO₃ can extract the elements in absorbed phases and those residing in non-silicate minerals. Six elements (Ba, Co, Fe, Ca, Mn, and P) generated significant correlations between total and HNO₃ in both OC and PC watersheds. Finally, the elements were grouped according to the interrelationships of their total elemental concentrations based on the dendrogram plots, suggesting their geochemical association in soils and sediment forming minerals.     

Earthworm populations in septic system filter fields and potential effects on wastewater renovation

Wastewater renovation in septic-system filter fields can be affected by preferential flow through soil macropores. Anecic earthworm species make deep vertical burrows that may reduce renovation by acting as preferential flow paths that decrease effluent contact with the soil matrix. On the other hand, endogeic earthworms make largely horizontal burrows that may enhance wastewater renovation by distributing the effluent over a larger area. Additionally, the moist, nutrient-rich environment in filter fields may increase earthworm populations by enhancing their survival. Therefore, our objectives were to determine earthworm numbers and biomass with distance from soil treatment trenches, and identify species present to estimate potential effects on wastewater renovation. Five septic systems were investigated. At each site, earthworm populations were measured using formalin extraction at 10 locations along each of three 7-m long transects perpendicular to the trenches. There were an average of 6.4 times more earthworms and 5.4 times more earthworm biomass within 1 m of the trench than in the background (3.5–7.0 m from the trenches) in 13 of the 15 transects. This suggests that earthworms may have a significant effect on the movement of effluent. Because only epigeic and endogeic species were observed, the potential for reduced renovation and groundwater contamination at these sites is likely low. This may not be the case in areas with large numbers of anecic earthworms.