Object recognition and generalisation during habituation in horses

The ability of horses to habituate to frightening stimuli greatly increases safety in the horse–human relationship. A recent experiment suggested, however, that habituation to frightening visual stimuli is relatively stimulus-specific in horses and that shape and colour are important factors for object generalisation (Christensen et al., 2008). In a series of experiments, we aimed to further explore the ability of horses (n = 30, 1 and 2-year-old mares) to recognise and generalise between objects during habituation. TEST horses (n = 15) were habituated to a complex object, composed of five simple objects of varying shape and colour, whereas CONTROL horses (n = 15) were habituated to the test arena, but not to the complex object. In the first experiment, we investigated whether TEST horses subsequently reacted less to i) simple objects that were previously part of the complex object (i.e. testing for object recognition) and ii) a novel object (new shape and colour, i.e. testing for object generalisation), compared to CONTROLS. In the second experiment we investigated whether TEST horses reacted to a change in object order and object location. Behavioural reactions to the object, latency to eat, total eating time and heart rate were recorded. Compared to CONTROLS, TEST horses reacted significantly less towards objects, which were previously part of the complex object (e.g. mean heart rate; P = 0.006), indicating object recognition. In contrast to our expectations, TEST horses also reacted significantly less towards the novel object (e.g. mean heart rate; P = 0.018), suggesting that they were capable of object generalisation. We also found that TEST horses showed an increase in exploratory behaviour when objects within the complex object changed order and location (both P < 0.001), whereas there was no increase in heart rate, indicating that the horses were not frightened by the changes. The results demonstrate that it is possible to increase object generalisation in horses by habituating them to a range of colours and shapes simultaneously. This knowledge greatly affects the way in which horses may be trained to react calmly towards frightening objects.     

Evaluation and comparison of four methods of ranking horses based on reactivity

Four methods of ranking horses on reactivity were evaluated and compared: isolation from conspecifics, presentation of a static novel stimulus, traversing a novel stimulus in a runway (isolation, novel stimulus and runway tests, respectively) and assigning subjective emotionality scores. In all tests, horses’ heart rates were recorded and behaviour was videotaped. To be considered a valid test of reactivity, at least one heart rate and one behavioural measurement in the test had to change significantly between treatments (tranquilizer administation versus sham tranquilizer administration), and behavioural measures had to be displayed in at least 75% of the trials. Forty horses performed each of the three tests daily on three different days in a switchback design. Horses were assigned randomly to a daily test sequence, which was maintained throughout the study. In the runway test, no significant difference in heart rate values in tranquilized and non-tranquilized horses was found, and no behavioural attribute was displayed in more than 52% of the trials; therefore it was rejected as a valid test of reactivity. Both isolation and novel stimulus tests produced valid measurements. Mean heart rate was the most precise physiological measure for these tests, and walking and defecation frequency were the most precise behavioural measures for novel stimulus and isolation tests, respectively. Mean heart rates on the novel stimulus and isolation tests were correlated (r_s = 0.79, P < 0.01) indicating that these tests produced similar rankings based on physiological responses. However, behavioural measures ranked horses differently (r_s = 0.27, P < 0.10) on the tests. Rank correlations between mean heart rates and behavioural measures were higher in the novel stimulus (r_s = 0.66, P < 0.01) than the isolation test (r_s = 0.55, P < 0.01), indicating that the novel stimulus test ranked horses based on either physiological or behavioural responses more similarly than did the isolation test. Therefore, the novel stimulus test was considered the more accurate evaluation of reactivity. Subjective emotionality scores were correlated moderately with mean heart rates (r_s > 0.33, P < 0.01) from the novel stimulus and isolation tests and with walking scores (r_s = 0.47, P < 0.01) from the novel stimulus test. Assignment of subjective emotionality scores was not as accurate as the novel stimulus or isolation tests in ranking horses for reactivity. Using physiological data alone, combining physiological and behavioural measurements or using more than one behavioural measurement in reactivity tests may reflect the reactivity of the horse better than a single behavioural measurement.     

Housing conditions and breed are associated with emotionality and cognitive abilities in riding school horses

Horses’ emotional reactivity is of a major importance in riding schools where a variety of more or less experienced riders are present. Horses’ learning abilities may also be important for work. Previous studies have shown that different intrinsic or extrinsic factors, such as breed, housing conditions, sire, and work may have an influence, and that different facilities present horses with different characteristics. In this study, we tested the reactions of 184 horses from 22 riding schools, all practicing the same type of work, but differing in particular in terms of housing conditions, to 3 emotionality tests and to one instrumental learning task, in order to (1) try and characterize riding schools, and (2) determine how general management could explain some of the potential differences observed between sites.Multivariate analysis conducted on the whole set of data showed that riding schools could be classified into four categories from those where horses showed low emotionality levels and good learning abilities to those where horses showed high emotionality levels and poor learning abilities. Breed, in accordance to previous studies, had an impact on the time to cross a novel obstacle in hand (“Bridge Test”) (Kruskall–Wallis, H (14, N = 184) = 27.08, p < 0.05) while housing conditions (e.g. box housing) influenced emotionality (emotionality index, MW: p < 0.05), when horses were released in the arena. Box housing was associated with more active locomotion patterns (including trot, canter and passage) (MW: p < 0.005). These results underline the importance for riding schools to take into account both the individual characteristics of the horse, and in particular the breed, and to consider the impact of general management including housing conditions, on horses’ reactivity, and its consequences in terms of human security.     

Visceral and Subcutaneous Fat Increased after Treatment of Graves Disease

Objective: Patients with Graves disease (GD) tend to gain weight after treatment, but it remains unknown if weight gain is associated with an increase in the visceral and/or subcutaneous fat areas (VFA, SFA).Methods: We enrolled 25 newly diagnosed GD patients (22 females, median age 33.0 years) and studied their clinical parameters, and VFA and SFA measured by a dual bioelectric impedance analysis. We divided them into 2 groups based on the rates of change in the VFA and SFA, and we compared clinical parameters at the baseline between the groups to evaluate factors that influence increases in the VFA and/or SFA with treatment.Results: The patients' body weight (BW), VFA, and SFA were significantly increased after a 6-month treatment (BW: from 54.3 ± 10.3 kg to 58.0 ± 11.2 kg; P<.001; VFA: from 47.1 ± 21.3 cm² to 54.7 ± 23.4 cm²; P = .004; SFA: from 159.8 ± 85.9 cm² to 182.2 ± 82.9 cm²; P = .008). The percent changes of BW correlated with the SFA (ρ = .591, P = .002), but not with the VFA. The patients with larger VFA increases had significantly less VFA at the baseline compared to those with smaller increases, expressed as median and interquartile range (33.9 cm² [22.7 to 47.5 cm²] versus 54.5 cm² [45.2 to 64.0], respectively; P = .011). A larger increase in the SFA was negatively associated with serum alkaline phosphatase. An increase in the SFA was associated with free triiodothyronine (T3) in a multivariate logistic analysis (odds ratio: 0.80 [0.59 to 0.97]; P = .013).Conclusion: The patients' BW, VFA, and SFA were increased after GD treatment. The increase in SFA seemed to contribute to weight gain and was associated with a low baseline level of free T3.Abbreviations: ALP = alkaline phosphatase; BMI = body mass index; BW = body weight; GD = Graves disease; SFA = subcutaneous fat area; T3 = triiodothyronine; T4 = thyroxine; TG = triglycerides; VFA = visceral fat areas     

Batch culture evaluation of carbohydrase inhibitors to moderate rumen fermentation

While carbohydrase inhibitors have been widely investigated for regulating human carbohydrate assimilation, their potential application to animal nutrition has been largely ignored. Batch culture fermentations were conducted to determine how commercially available α-amylase and α-glucosidase inhibitors affect rumen fermentation. Fermentations were with 0.5 g of ground corn grain, and 40 mL of buffered rumen fluid inoculum. Rumen fluid donors were fed a 0.5 concentrate 0.5 forage diet. Incubations were conducted in duplicate and replicated on consecutive days with pH and volatile fatty acid (VFA) concentrations measured. The microbial-derived inhibitors, acarbose (ACB) and trestatin (TRE), prevented the decreases in pH and VFA production observed in the control tubes at doses of 1.2–9.5 and 0.1–1.1 mg, respectively. Miglitol, glipizide, and the plant-derived amylase inhibitors failed to affect pH or reduce VFA concentrations with the same apparent potency as did ACB and TRE, which both show the potential to reduce the amount of starch fermented in the rumen. These compounds may be potentially useful for reducing ruminal acid production and allowing more starch to pass to the small intestine from the forestomachs.     

Effect of high tannin grain sorghum on gastrointestinal parasite fecal egg counts in goats

The objective of three experiments was to determine the influence of high condensed tannin (CT) grain sorghum on gastrointestinal parasite fecal egg counts (FEC). Sixteen naturally infected Boer crossbred mixed-sex goats were used. Animals that were supplemented with grain daily were removed from pasture and placed in individual pens and fed treatment diets for 21 or 14 days (Experiment 3). Goats were allowed ad libitum access to water and diets containing high or low CT cracked grain sorghum. On day 0 and every 7 days thereafter, PCV, FEC and FAMACHA^® eyelid color scores (EYE; Experiment 1 only) were recorded. For Experiment 1, percentage of animals dewormed, PCV and EYE were not influenced by treatment and averaged 13.6 ± 4.5% per treatment period, 23.4 ± 0.8% and 3.2 ± 0.12, respectively, for all animals. The FEC increased after day 0 for control but not high tannin grain sorghum fed goats (treatment by day interaction, P < 0.02). As expected, EYE and PCV were negatively related (r = −0.45; P < 0.0005). For Experiment 2, there was no influence of diet on PCV or FEC, but there was an effect of day on FEC (P < 0.002) in which all goats had higher FEC on day 0 (1956 ± 219 eggs/g) than any other sampling day. For Experiment 3, there was no effect of feeding high CT grain sorghum on FEC (2992 ± 591 eggs/g) or PCV (25.1 ± 0.5%). In these studies, high CT grain sorghum did not consistently influence FEC and did not impact PCV or number of animals requiring chemical anthelmintic treatment.     

In situ degradability of seven plant protein supplements in heifers fed high concentrate diets with different forage to concentrate ratio

Four Holstein heifers (297.5 ± 27.7 kg BW) fed high concentrate diets were used in a crossover experiment in order to characterize the rumen fermentation pattern, and to estimate by the in situ method rumen degradation kinetics of alfalfa hay and seven plant protein supplements: solvent-extracted soybean meal, solvent-extracted sunflower meal, peas (Pisum sativum L.), lupin seeds (Lupinus sp.), broadbean (Vicia faba L.), horsebean (Vicia faba L. var equina) and vetch (Vicia sativa L.), in high concentrate diets with different forage to concentrate ratio. Heifers were fitted with a ruminal cannula. The experiment was performed in two 30-day periods, 15 days of diet adaptation and 15 days of sampling. At each period, heifers were offered one of two total mixed rations (12:88 versus 30:70 forage to concentrate ratio), two heifers per diet, on ad libitum basis. After the first period, heifers switched treatments. Intake of dry matter (DM), organic matter, crude protein and neutral detergent fibre (NDF), expressed as kg/day, did not differ between treatments, but DM intake, expressed as g/kg metabolic body weight (BW), was higher in the 12:88 diet. Average rumen pH was 6.0 in both diets, and the time pH was below 5.8, which is considered as a critical threshold for fibre degradation, was the same for both treatments (10.4 ± 1.6 h). Average ammonia nitrogen and volatile fatty acid (VFA) concentrations did not differ between treatments and individual VFA proportions were typical of high concentrate diets. Average effective degradability of DM (0.62 ± 0.02) and NDF (0.25 ± 0.03) of alfalfa hay were low and no differences were detected between treatments. The same extent of NDF degradation, together with the same proportions of VFA would indicate that both diets had the same fibrolytic activity. Forage to concentrate ratio did not affect rumen nitrogen degradability of any protein supplements incubated in situ. Corrected effective degradability for small particle losses of sunflower meal (0.78) was higher than legume seeds, which were not statistically different between each other and ranged from 0.63 to 0.66. Soybean meal had the lowest degradability value (0.61). These nitrogen degradation values must be considered more valid for beef cattle formulation of high concentrate diets than data obtained with forage diets.     

Interpretation of rumen degradability of concentrate feeds with a Gompertz model

An investigation of the kinetics and synchronicity of rumen crude protein and starch degradability was performed for maize, flaked maize, ensiled maize cob, barley, flaked barley, wheat, oat, sorghum and triticale grain, using the in situ polyester bag technique. Kinetics of rumen degradability were corrected for particle losses from the bag before degradation. Washing losses were measured by shaking feed samples in polyester bags in tap water at 20°C for 1 h and recovering the particle losses in fibre glass filter. Mean washing losses of dry matter were 442 g/kg DM (soluble fraction 17%); mean washing losses of nitrogen were 446 g/kg nitrogen, with 52% being water soluble. Starch escaped to a higher extent from the bags in the washing machine (average washing losses were 581 g/kg starch, with a soluble fraction of 7%). Degradability data for dry matter, nitrogen and starch measured at each time of incubation were corrected for the respective particle losses and fitted with both first order and Gompertz (sigmoidal) models. The difference between the estimated parameters obtained with the two models was negligible, although differences occurred for the immediately soluble fraction (a) of dry matter and starch and for total degradable fractions of dry matter, nitrogen and starch. No differences were observed between effective degradabilities, independent of rumen outflow rate (0.04 and 0.08/h), apart for the mean effective degradability of nitrogen at 0.08/h, which was higher for the first order model (577 versus 564 g/kg, P < 0.001). The advantage of using the Gompertz model to interpret the kinetics of rumen degradability of cereals was due to the possibility of studying synchronicity of nitrogen and starch released into the rumen and ranking feeds according to their degradability pattern, which required the calculation of the first derivatives of the Gompertz model for nitrogen and starch and weighted for their respective amounts in the feeds. The difference of these ratios from the optimum value of 30 mg N per 1 g starch gives the instantaneous synchronicity of the cereals. Maize, flaked maize, maize cob and sorghum had negative and almost constant values during the first 8 h of incubation. Barley, flaked barley, wheat, triticale and oat changed from an initially negative value to a positive value from about 4 h onwards; oats had a similar pattern, but a positive value was observed only after 6 h.     

Impact of barley form on equine total tract fibre digestibility and colonic microbiota

This study aimed at assessing the impact of four barley forms on total tract apparent digestibility of dietary fibre in horses fed a large amount of starch in the morning meal (0.27% BW). Processed barley forms had a greater pre-caecal starch digestibility than the whole form. Based on this result, we hypothesised that using barley-processing methods would limit the potential dumping of undegraded starch in the hindgut of horses and, consequently, the potential negative effect on fibre degradation in the hindgut. In a 4×4 latin square design, four mature geldings fitted with a right ventral colon-fistula were fed a meadow hay : concentrate (62 : 38; dry matter (DM) basis) diet at 1.7% BW. The concentrate was made of 80% barley distributed either as whole grain or as processed forms: 2.5 mm ground, pelleted or steam-flaked. For each period, total tract apparent digestibilities of DM, NDF and ADF were determined over 3 consecutive days by total faecal collection, whereas pH, volatile fatty acids (VFA) concentrations and cultural functional bacteria counts (total anaerobic, cellulolytic bacteria, lactic acid producers, amylolytic bacteria and lactic acid utilisers) in colonic content were evaluated on 1 day 4 h after the morning meal. Total tract apparent digestibility of DM and dietary fibre was influenced (P<0.05) by barley form. Diets including thermo-mechanically treated barley forms led to a higher (P<0.05) total tract apparent digestibility of NDF than those constituted of ground barley and also led to a greater (P<0.05) total tract apparent digestibility of ADF than those made of whole or ground barley forms. However, no significant difference was observed in colonic pH, VFA concentrations and cultural bacteria concentrations. Owing to a high starch supply in the morning meal, the concentration of the functional bacteria in the colonic content averaged 7.8 log CFU/ml, 5.9 NPM/ml, 6.9 and 7.3 CFU/ml for total anaerobic, cellulolytic, amylolytic and lactic acid-utilising bacteria, respectively. Consequently, providing horses with pelleted or steam-flaked instead of ground barley forms may limit the negative impact of starch on fibre digestibility in horses fed a high level of starch in the morning meal (0.27% BW). Moreover, the fibre-to-starch ratio fed in this experiment did not cause any digestive upset.     

Assessment of the efficacy of varying experimental exogenous fibrolytic enzymes using in vitro fermentation characteristics

This study evaluated a series of recombinant, single activity experimental enzyme products including 13 endoglucanases (END) and 10 xylanases (XY), for their potential to improve in vitro ruminal degradation of alfalfa hay in two experiments. Based on the endoglucanase or xylanase enzymatic activities measured using complex substrates at the optimal conditions (pH 5.4, 37 °C) for the enzymes, a dose level (1 unit/g dry matter [DM]) was chosen for addition of enzymes to substrate. Enzyme products, re-suspended with water, were added to alfalfa hay (0.5 or 1.0 g DM) in culture vials in six replications. Anaerobic buffer medium (20 or 40 ml) adjusted to pH 6.0 and strained ruminal fluid (5 or 10 ml) were sequentially added to the vials and incubated for 18 h. Headspace gas production (GP) was measured throughout the incubation, and degradability of organic matter (OMD) and fibre and volatile fatty acid (VFA) concentrations were determined after 18 h of incubation. The enzyme products had a wide range of added endoglucanase or xylanase activities when determined using pure substrates and physiological conditions typical of the rumen (pH 6.0, 39 °C). In experiment 1, many END, and some XY, products increased GP and OMD. The correlation between added endoglucanase activity determined at ruminal conditions and OMD improvement was high (r = 0.71; P<0.01), whereas added activity of xylanase was not associated with OMD improvement. Two END and two XY products selected from experiment 1 were further assessed because they substantially improved GP and OMD. In experiment 2, all enzyme treatments, alone or in combination, increased total GP and DM and fibre degradabilities (P<0.05). However, the combinations of END and XY did not increase degradation of alfalfa beyond that of the component enzymes. Total VFA production was not affected by enzyme treatments although some products changed the acetate to propionate ratio. Experimental exogenous enzyme products with either endoglucanase or xylanase activity substantially improved in vitro ruminal degradation of alfalfa hay, but further improvement by combining these activities did not occur.     

Silver glyconanoparticles functionalized with sugars of sweet sorghum syrup as an antimicrobial agent

Bio-directed synthesis of metal nanoparticles is gaining importance due to their biocompatibility, low toxicity and eco-friendly nature. We used sweet sorghum syrup for a facile and cost-effective green synthesis of silver glyconanoparticles. Silver nanoparticles were formed due to reduction of silver ions when silver nitrate solution was treated with sorghum syrup solutions of different pH values. The nanoparticles were characterized by UV–vis, TEM (transmission electron microscopy), DLS (dynamic light scattering), EDAX (energy dispersive X-ray spectroscopy), FT-IR (fourier transform infrared spectroscopy) and XRD (X-ray diffraction spectroscopy). The silver glyconanoparticles exhibited a characteristic surface plasmon resonance around 385 nm. At pH 8.5, the nanoparticles were mono-dispersed and spherical in shape with average particle size of 11.2 nm. The XRD and SAED studies suggested that the nanoparticles were crystalline in nature. EDAX analysis showed the presence of elemental silver signal in the synthesized glyconanoparticles. FT-IR analysis revealed that glucose, fructose and sucrose present in sorghum syrup acted as capping ligands. Silver glyconanoparticles prepared at pH 8.5 had a zeta potential of ?28.9 mV and were anionic charged. They exhibited strong antimicrobial activity against Gram-positive, Gram-negative and different Candida species at MIC values ranging between 2 and 32 μg ml^?1. This is first report on sweet sorghum syrup sugars-derived silver glyconanoparticles with antimicrobial property.     

The relationship between the volatile fatty acids supply and the nitrogen retention in growing sheep nourished by total intragastric infusions

Twelve four-month old Suffolk × Small-tail-Han male sheep (live weight 21–26 kg), fitted with rumen and abomasum fistulas and nourished by total intragastric infusions, were used to study the relationship between the volatile fatty acids (VFA) supply and the nitrogen (N) retention in sheep. The animals were randomly divided into four groups and four levels of mixed VFA energy (the molar proportion of acetic acid, propionic acid and butyric acid was 65:25:10), i.e. 333, 378, 423 and 468 kJ kg^?1 W^0.75 d^?1, were infused into the rumen, as treatments I, II, III and IV, respectively. The results showed that the N retention was significantly increased (P < 0.05) with the VFA infusion level. Significant regression relationship was found between the VFA supply (x, g d^?1) and the N retention (y, mg d^?1): y = 2.75x ? 403, r² = 0.86, n = 12, P < 0.01. It was concluded that to get efficient utilization of dietary N and high N retention in sheep, it is necessary to supply enough dietary energy.     

Impact of riding in a coercively obtained Rollkur posture on welfare and fear of performance horses

Rollkur, the usually coercively obtained hyperflexion of the horse's neck, is employed as a training method by some dressage riders; however, its use is controversial as it may cause discomfort and adversely affect the horse's welfare. The objectives of this study were to determine: (1) if horses showed differences in stress, discomfort and fear responses as measured by heart rate and behaviour when ridden in Rollkur (R) obtained by pressure on the reins compared to regular poll flexion (i.e. with the nose-line being at or just in front of the vertical; N), and (2) if they showed a preference between the two riding styles when given the choice. Fifteen riding horses were ridden 30 times through a Y-maze randomly alternating between sides. Riding through one arm of the Y-maze was always followed by a short round ridden in R, whereas riding through the other arm was followed by a short round ridden in N. Immediately after the conditioning phase, horses were again repeatedly ridden into the maze; however, riders left it to the horse to decide which arm of the maze to enter. During R, horses moved slower and showed more often behavioural signs of discomfort, such as tail-swishing, head-tossing or attempted bucks (P < 0.05), and 14 of the 15 horses chose significantly (P < 0.05) more often the maze-arm associated with N rather than R. Subsequently, eight of the horses were also subjected to two fear tests following a short ride in N as well as a ride in R. During R, horses tended to react stronger (P = 0.092) to the fear stimuli and to take longer (P = 0.087) to approach them. These findings indicate that a coercively obtained Rollkur position may be uncomfortable for horses and that it makes them more fearful and therefore potentially more dangerous to ride. Further studies need to assess horses’ reaction to gradual training of Rollkur, as opposed to a coercively obtained hyperflexion, in order to decide whether the practice should be banned.     

Seroprevalence of Babesia caballi and Theileria equi in the Swiss horse population

In Switzerland, the prevalence and incidence of equine piroplasma parasite (EPP) infections are unknown. In order to obtain a first insight into the prevalence, a representative sample of 689 sera of horses from Switzerland was serologically tested for the presence of antibodies directed against T. equi and B. caballi using the Indirect Fluorescence Antibody Test (IFAT). A total of 50 (7.3%) horses were seropositive for EPP: overall, the seroprevalence of T. equi was significantly higher than that of B. caballi (p = 0.002). The seropositivities in indigenous horses (animals bred and raised in Switzerland) and in imported horses were 4.8% (11/230) and 8.5% (39/459), respectively. Unlike in indigenous horses, where no significant difference in seroprevalences could be observed between the two parasite species, the seroprevalence of T. equi was significantly higher (p < 0.001) than that of B. caballi in imported horses. Horses imported from France, Spain and Portugal exhibited a significantly higher seroprevalence, and horses imported from Germany a significantly lower seroprevalence of EPP compared to indigenous horses. There were no associations between sex, age, weight loss, surgery or blood transfusions with T. equi and B. caballi seroprevalences.The overall seroprevalence of 7.3% clearly shows that infection with EPP is a threat to the health of the horses in Switzerland. With the presumed expansion of permissive tick vectors, EPP infections will potentially increase in importance in the future. Therefore, continuous monitoring is mandatory.     

Effects of postmortem carcass electrical stimulation on goat meat quality characteristics

Electrical stimulation (ES) has been reported to improve meat quality, but the effects of postmortem ES have not been fully characterized in goats. This experiment was conducted to determine the effects of postmortem ES on meat quality in two breeds of goats. Uncastrated Spanish and crossbreds (Boer × Spanish females × Kiko male) yearlings (n = 10/breed, body weight 31.2 ± 2.43 kg) were transported to the slaughter facility, held overnight in pens without feed, and slaughtered on two different days. Immediately after slaughter each carcass was split into two halves along the vertebral column. The left half was subjected to a high voltage ES (580 V) at 5 s intervals during 120 s (treatment) and the right half was kept as a non-stimulated control. After 24 h of cooler storage (2 °C), the carcasses were fabricated into 2.5 cm-thick loin/rib chops. Longissimus dorsi (LD) muscle pH and temperatures were recorded at 0, 1, 2, 3, 4, 5, 6, 9, 12, 15, 18, and 24 h postmortem. The pH values of LD muscle were lower in stimulated sides than control sides (P < 0.01), and pH decreased quadratically (P < 0.01) with advancing time during the 24 h postmortem period. Treatment had no significant effect on the LD muscle temperature, and the temperature decline followed a cubic pattern (P < 0.01) during the 24 h postmortem period. Muscle glycogen concentrations immediately after electrical stimulation (0 h) were lower (P < 0.05) in the stimulated sides compared to control sides. Warner-Bratzler shear force (WBSF) values of loin chops were lower (P < 0.01) in stimulated sides (3.0 kg) compared to control sides (4.2 kg), and the chops from Spanish goats (3.9 kg) had higher (P < 0.05) WBSF values compared with crossbreds (3.3 kg). Color values (L*, a*, b*, chroma, and hue angle) and sarcomere length were not affected by ES or breed. Heated calpastatin activities were not influenced by ES, but the activities were lower at day 4 compared with day 1 of aging (P < 0.05). There were no significant effects (P > 0.05) of ES or aging time on selected myofibrillar protein concentrations (myosin heavy chain, myomesin, desmin, actin, troponin-T, and myosin light chain, P > 0.05). However, desmin concentration tended to decrease at day 4 of aging (P = 0.08). The results indicate that ES significantly accelerated postmortem glycolysis and improved tenderness of loin chops, as indicated by WBSF values.     

Lactobacillus plantarum effects on silage fermentation and in vitro microbial yield

In four parallel experiments, herbage [three harvests of alfalfa (308 to 379 g dry matter (DM)/kg), one of whole-plant corn (331 g DM/kg)] was ensiled with three different treatments: no inoculant (control), Lactobacillus plantarum (LP) or formic acid (FA), in 1-L mini-silos and fermented for 60 d at room temperature (22 °C). Mini-silos were opened and analyzed for fermentation characteristics and soluble N fractions. A subsample of wet silage from each mini-silo was ground to 4 mm and stored at ?20 °C. Silages were thawed and subjected to 9 h ruminal in vitro incubations to measure gas production and volatile fatty acid (VFA) production as well as microbial biomass yield (MBY) and microbial non-ammonia N (MNAN) formation using ¹⁵N as a marker. In all four experiments, silage fermentation products and pH indicated good preservation across all treatments. Analysis of data showed that FA- and LP-treated silages had lower concentrations of ammonia-N and free amino acids N than control. The FA treatment was lower in soluble N, but higher in peptide-N, than control. Silage pH was lowest in FA (4.25), followed by LP (4.28), and control (4.38). Ruminal in vitro gas production and VFA concentrations were not different among treatments (P>0.05). Compared to control, FA- and LP-treated silage yielded greater MNAN and MBY. These findings suggested that L. plantarum preserved more true protein during silage fermentation than control, which in turn increased in vitro ruminal microbial growth.     

Evaluating agro-industrial by-products as dietary roughage source on growth performance of fattening steers

Silages from pineapple peel, sweet corn husk and cob mixed with bagasse and vinasse were evaluated to determine their chemical composition and fermentation characteristics as well as feeding performance in fattening steers. The experiment, which lasted 90 days, involved 48 fattening steers (264 ± 37.4 kg BW) randomly allocated to three diets. Treatments included: a control diet containing rice straw and molasses (T1); diet containing bagasse–vinasse mixture including sweet corn husk and cob silage (BS; T2); and diet containing bagasse–vinasse mixture including pineapple peel silage (BP; T3). All treatments included a commercial concentrate feed (13% CP) and ad libitum rice straw throughout the experiment. Results from chemical analysis showed that dry matter (DM) of BS was higher than BP (P < 0.05), whereas the protein content of BS and BP was similar (P > 0.05). For fermentation characteristics, pH in BP was lower than BS (P < 0.05); in addition, acetic and butyric acids in BS were higher than BP (P < 0.05). Findings from growth trial showed that total DM intake in steers fed T1 was higher compared to the other dietary treatments (P < 0.05), whereas the average BW gain was found to be grater in T3 steers (P < 0.05). As result from our findings, bagasse–vinasse mixture with pineapple peel silage appeared to be a viable feed ingredient in fattening steer diet and moreover it could become an economically feasible agro-industrial by-product for farmers.     

Properties of the isoforms of α-amylase from kilned and unkilned malted sorghum (Sorghum bicolor)

We have previously reported the presence of a relatively heat-stable α-amylase with a low K_m for starch in kilned malted sorghum. In order to establish the industrially useful and more efficient isoforms, we have separated this α-amylase into different isoforms using both cation and anion-exchange chromatographies. Unkilned malted α-amylase crude was separated into three different isoforms (a1, a2 and a3) whereas kilned samples were separated into two (a1 and a2). Apparently one isoform (a3) was lost during kilning due to heat lability. a1 isoform which appears to have a neutral pI and constitute about 60% of the total α-amylases protein that were induced during germination, have the lowest K_m for starch. They are more generally stable than other isoforms at all the temperatures studied. These isoforms lost only 10% activity at 80 °C for 30 min and still had some residual activity at 100 °C incubation for 30 min. a1 isoform could therefore be adapted for industrial starch conversion processes which are carried out within this range of gelatinizing temperatures because of its properties.     

Meat quality in goats as influenced by dietary protein and energy levels,and postmortem aging

The objectives of this study were to determine effects of different dietary treatments and postmortem aging on meat quality characteristics in goats. Twenty castrated dairy goats (BW = 30.7 ± 6.80 kg, age 10 months) were subjected to one of four dietary treatments for 82 days (treatment): (i) 2.5 Mcal/kg DM DE and 12% CP, (ii) 2.5 Mcal/kg DM DE and 18% CP, (iii) 2.9 Mcal/kg DM DE and 12% CP, or (iv) 2.9 Mcal/kg DM DE and 18% CP. At the end of the feeding trial, the animals were slaughtered to evaluate meat quality. Longissimus muscle pH and temperature were measured at 0, 3, 6, 9, 12, 15, 18, and 24 h postmortem (time). Sarcomere length (1.65 μm), total collagen (4.17 mg/g), and heated calpastatin (44.7 units) measured at 24 h postmortem were not influenced by treatment (P > 0.05). Warner–Bratzler shear force values, collagen solubility, and cooking losses of loin/rib chops (2.5 cm thick) aged for 1, 3, or 6 days postmortem were not influenced by treatment (P > 0.05) or aging time (P > 0.05). Postmortem sampling time affected muscle pH and temperature decline (P < 0.01), but there was no effect of treatment. There was a trend toward a treatment × time interaction (P < 0.06) in muscle pH. Temperature and pH declines followed cubic (P < 0.01) and linear (P < 0.01) trends, respectively. Average muscle temperature declined rapidly and reached 14.5 ± 2.0 °C at 3 h postmortem, while the pH was still high (6.60 ± 0.087). In conclusion, diet did not influence meat quality characteristics, and shear force values of chevon did not decrease due to postmortem aging. Rapid heat dissipation from goat carcasses during too rapid chilling may have caused cold shortening of muscles resulting in meat that did not respond to aging.     

Effect of partial replacement of concentrates with jackfruit (Artocarpus heterophyllus) leaves on growth performance of kids grazing on native pasture of Tripura,India

Fifteen Black Bengal kids of about 3 months of age and body weight ranging from 3.8 to 4.9 kg were randomly distributed into three groups of five. Kids grazed native pasture 8 h/d. The kids in group I received supplementary concentrate (maize 35%, mustard cake 32%, rice bran 30%, mineral mixture 2% and common salt 1%) at approximately 2% of BW. However, 25 and 50% of the concentrate was replaced with jackfruit leaves for groups II and III, respectively. Total dry matter intake (DMI) was significantly higher in groups II and III than for group I due to greater forage consumption. Digestibility of CP (P < 0.05) decreased and that of NDF increased (P < 0.01) with increasing level of jackfruit leaves in the diet. Digestibility of ADF (P < 0.01), hemi cellulose (P < 0.05) and cellulose (P < 0.01) was higher in groups II and III in comparison to group I. Ruminal pH and TVFA concentration were not significantly different among the groups; however, rumen ammonia-N concentration decreased (P < 0.01) with increased level of jackfruit leaves in the diet. Similarly, plasma urea nitrogen and blood glucose levels were also reduced (P < 0.05) with increasing level of jackfruit leaves in the diet Average daily gain (ADG) was 47.33, 45.11 and 35.56 g/d in groups I, II and III, respectively. ADG and DMI/kg gain were not adversely affected when the level of replacement was restricted to 25%; however, at the 50% of replacement both parameters were adversely affected (P < 0.05). From the results of this experiment, it was concluded that jackfruit leaves might replace 25% of the supplemental concentrate for growing kids grazing in native pasture of northeast India.