Impact of animal density on cattle nutrition in dry Mediterranean rangelands: a faecal near-IR spectroscopy-aided study.

In the context of determining the sustainable carrying capacity of dry-Mediterranean herbaceous rangelands, we examined the effect of animal density on cattle nutrition, which is fundamental to animal performance and welfare. The effects on dietary components of low (0.56 cows/ha; L) and high (1.11 cows/ha; H) animal densities were monitored for three consecutive years in grazing beef cows. In the dry season (summer and early autumn), cows had free access to N-rich poultry litter (PL) given as a dietary supplement. In each season, near-IR spectroscopy (NIRS) was used to predict the chemical composition of herbage samples (ash, NDF, CP, in vitro dry matter digestibility (IVDMD) and metabolizable energy (ME) content from IVDMD). Near-IR spectroscopy was applied also to faecal samples to determine the chemical composition of the diet selected by the animal, as well as the contents of ash, NDF and CP in the faeces themselves. A faecal-NIRS equation was applied to estimate the dietary proportion of PL. Seasonal categories were green, dry without PL supplementation and dry with it. We found no effects of animal density on nutrition during the green season but effects were apparent when cows consumed dry pasture. Ash content predicted by faecal NIRS was higher in the diet than in plant samples clipped from pasture, which infers that cows ingested soil. Dietary and faecal ash contents were higher (P<0.05) at the H, implying greater soil intake in these animals. During the dry period, dietary contents of ME were higher in L than in H (P<0.05). Poultry litter supplementation was associated with a marked increase (P<0.01) in dietary and faecal CP contents. Poultry litter represented 0.45 and 0.59 of the diet in treatments L and H, respectively (P<0.05). Consequently, treatment H had higher faecal protein (P<0.05). A tendency of higher dietary protein (P=0.08) and lower dietary NDF (P=0.10) in treatment H was probably related to greater PL ingestion. Given that high and sustained rates of poultry litter consumption are detrimental to animal health, the above results cast doubts on the long-term sustainability of the higher of the animal densities tested. Although it may be sustainable vis-à-vis the vegetation, treatment H may have exceeded the boundaries of what is acceptable for cow health. Chemical information revealed with NIRS can be used to evaluate whether animal densities are compatible with animal health and welfare standards and can play a role in determining the carrying capacity of Mediterranean rangelands.

Evaluation of the IceTag leg sensor and its derivative models to predict behaviour, using beef cattle on rangeland.

BACKGROUND: There is interest in using animal-mounted sensors to provide the detailed timeline of domesticated ruminant behaviour on rangelands. NEW METHOD: Working with beef cattle, we evaluated the pedometer-like IceTag device (IceRobotics, Edinburgh, Scotland) that records step events, leg movement and body position (upright versus lying). We used partition analysis to compare behaviour as inferred from the device data with true behaviour as coded at high resolution from carefully synchronized video observations of 5-min duration. RESULTS: Malfunctions reduced the target dataset by 7%. The correspondence between IceTag and video-coded step counts was excellent (r2=0.97), and the device's indications of upright or lying corresponded well (error rate=1.4%) to the video-coded values. However, the proportion of steps that could be matched individually was relatively low (65% at a tolerance of 0.5s), and the indicated start of a lying bout was often triggered by leg movements of an upright animal. Partition analysis of Grazing versus Not-Grazing yielded an overall error rate of 22%. In both three- and four-way classifications of behaviour (Graze, Rest, Travel; Graze, Stand, Lie, Travel) error rates were low for non-graze behaviours, but only 25% of Graze observations were correctly classified; the overall error rate was 22%. COMPARISON WITH EXISTING METHOD(S): The IceTag device performed well in mapping the diurnal patterns of animal position and step rate, but less well in separating grazing from upright resting. CONCLUSIONS: Our results suggest that pedometry is not the ideal method for classifying behaviour when grazing is of paramount interest.

Faecal near-IR spectroscopy to determine the nutritional value of diets consumed by beef cattle in east Mediterranean rangelands.

Rapid assessment of the nutritional quality of diets ingested by grazing animals is pivotal for successful cow-calf management in east Mediterranean rangelands, which receive unpredictable rainfall and are subject to hot-spells. Clipped vegetation samples are seldom representative of diets consumed, as cows locate and graze selectively. In contrast, faeces are easily sampled and their near-IR spectra contain information about nutrients and their utilization. However, a pre-requisite for successful faecal near-infrared reflectance spectroscopy (FNIRS) is that the calibration database encompass the spectral variability of samples to be analyzed. Using confined beef cows in Northern and Southern Israel, we calibrated prediction equations based on individual pairs of known dietary attributes and the NIR spectra of associated faeces (n=125). Diets were composed of fresh-cut green fodder of monocots (wheat and barley), dicots (safflower and garden pea) and natural pasture collected at various phenological states over 2 consecutive years, and, optionally, supplements of barley grain and dried poultry litter. A total of 48 additional pairs of faeces and diets sourced from cows fed six complete mixed rations covering a wide range of energy and CP concentrations. Precision (linearity of calibration, R2cal, and of cross-validation, R2cv) and accuracy (standard error of cross-validation, SEcv) were criteria for calibration quality. The calibrations for dietary ash, CP, NDF and in vitro dry matter digestibility yielded R2cal values >0.87, R2cv of 0.81 to 0.89 and SEcv values of 16, 13, 39 and 31 g/kg dry matter, respectively. Equations for nutrient intake were of low quality, with the exception of CP. Evaluation of FNIRS predictions was carried out with grazing animals supplemented or not with poultry litter, and implementation of the method in one herd over 2 years is presented. The potential usefulness of equations was also established by calculating the Mahalanobis (H) distance to the spectral centroid of a calibration population of 796 faecal samples collected throughout 2 years in four herds. Seasonal trends in pasture quality and responses to management practices were identified adequately and H<3.0 for 98% of faecal samples collected. We conclude that the development of FNIRS equations with confined animals is not only unexpensive and ethically acceptable, but their predictions are also sufficiently accurate to monitor dietary composition (but not intake) of beef cattle in east Mediterranean rangelands.

Foraging behavior of two cattle breeds, a whole-year study: II. Spatial distribution by breed and season.

Spatial distributions of 22 mature large-framed Beefmaster × Simford (BS) cross cows and 16 mature small-framed Baladi (BA) cows were determined. Cows were allocated to the same paddock of a Mediterranean pasture and monitored during 6 consecutive seasons: spring (April 2006), summer (June 2006), autumn (September 2006), winter (February 2007), early spring (March 2007), and summer (June 2007). The locations of the cows were determined at 5-min intervals for 3 to 4 d during each season by using Global Positioning System (GPS) collars. The distances between consecutive locations and the average locations of each breed at each hour of the day in each season were calculated. The Lateral Foraging Index (LFI) was calculated as the ratio between the average distance per day travelled by the cows of each breed and the perimeter of the diurnal itinerary of that breed, which was calculated from its hourly average locations. The 2 breeds maintained similar diurnal patterns of foraging and resting, characterized by morning and afternoon foraging, and resting at midday and during the night. In summer this pattern was more distinctive, with longer resting periods and more intense foraging periods than in winter, when the noon rest was shorter and only partial. The diurnal routes differed (P < 0.001) between the breeds in all seasons, in their locations, their travelling time, or both. The BA cows were more active than the BS cows in all seasons: they travelled longer distances (P < 0.001) and foraged for more hours during the day (P < 0.001). For both breeds the LFI was numerically greater in winter and spring (February, and March) than in summer (June and September), and it was numerically greater for BA than for BS cows in most seasons.

Self-medication with tannin-rich browse in goats infected with gastro-intestinal nematodes.

Primates self-medicate to alleviate symptoms caused by gastro-intestinal nematodes (GIN) by consuming plants that contain secondary compounds. Would goats display the same dietary acumen? Circumstantial evidence suggests they could: goats in Mediterranean rangelands containing a shrub - Pistacia lentiscus - with known anthelmintic properties consume significant amounts of the shrub, particularly in the fall when the probability of being infected with GIN is greatest, even though its tannins impair protein metabolism and deter herbivory. In order to test rigorously the self-medication hypothesis in goats, we conducted a controlled study using 21 GIN-infected and 23 non-infected goats exposed to browse foliage from P. lentiscus, another browse species - Phillyrea latifolia, or hay during the build-up of infection. GIN-infected goats showed clear symptoms of infection, which was alleviated by P. lentiscus foliage but ingesting P. lentiscus had a detrimental effect on protein metabolism in the absence of disease. When given a choice between P. lentiscus and hay, infected goats of the Mamber breed showed higher preference for P. lentiscus than non-infected counterparts, in particular if they had been exposed to Phillyrea latifolia before. This was not found in Damascus goats. Damascus goats, which exhibit higher propensity to consume P. lentiscus may use it as a drug prophylactically, whereas Mamber goats, which are more reluctant to ingest it, select P. lentiscus foliage therapeutically. These results hint at subtle trade-offs between the roles of P. lentiscus as a food, a toxin and a medicine. This is the first evidence of self-medication in goats under controlled conditions. Endorsing the concept of self-medication could greatly modify the current paradigm of veterinary parasitology whereby man decides when and how to treat GIN-infected animals, and result in transferring this decision to the animals themselves.

Foraging behavior of two cattle breeds, a whole-year study: I. Heat production, activity, and energy costs.

The foraging behavior and energy costs of activity of 19 large-frame Beefmaster × Simford (BS) cross mature cows and 14 small-frame Baladi (BA) mature cows was determined. Cows were allocated to the same paddock of a Mediterranean pasture and were monitored during 5 seasons throughout 2006 and 2007: spring (April 2006), summer (June 2006), autumn (September 2006), winter (February 2007), and early spring (March 2007). Cows were given poultry litter (25% CP, DM basis) as supplemental feed during autumn only. The cows were fitted for 3 to 4 d in each season with global positioning system (GPS) monitors, activity monitors attached to 1 of their hind legs, and heart rate (HR) monitors harnessed to their chests. Oxygen consumption per heart beat was determined for each cow during each season to enable conversion of the diurnal HR patterns to heat production (HP) units. All GPS data of cattle locations and activity and the HR and HP data were synchronized to produce simultaneous 5-min interval records; step length also was calculated for each record. These records provided summaries of partitioning among activities: lying down, standing, foraging, and walking without foraging as well as horizontal and vertical distances walked per day and number of steps taken per day. These attributes were analyzed using multiple regression models to relate these activities to HP and to estimate specific HP costs per unit of each activity. Accordingly, the daily energy costs of activity were calculated for the 2 cattle types in each season as the product of the specific activity and the number of units of each activity per day. The HP level of the large-frame BS cows was greater than that of the small-frame BA cows in winter and lower in spring (P < 0.001); however, the respective HP levels were much closer in summer and autumn, with BA cows having values greater by 3% than those of BS cows. The BA cows were more active than the BS cows during all seasons: they foraged for more hours per day (P < 0.001) and walked longer distances (P < 0.001). The mean specific costs of activity of BA cows were 20% less than those of BS cows (P < 0.001). The BA cows took longer steps during foraging and walking idle compared with BS cows despite their much smaller frame. The BA cows were more efficient in conditions of low herbage quality whereas metabolic rate of BS cows was greater in conditions of high herbage quality.

Polyphenols from Pistacia lentiscus and Phillyrea latifolia impair the exsheathment of gastro-intestinal nematode larvae.

The infection of grazing ruminants with gastro-intestinal nematodes (GINs) is a severe problem in the Middle East. However, goats that graze the south-western slopes of the Carmel Heights in Israel have very low faecal egg counts, despite high grazing density. We hypothesized that polyphenols from Pistacia lentiscus L. and/or Phillyrea latifolia L. - both prevalent woody species of the region that are consumed by goats - have anthelmintic bioactivity. We tested this hypothesis by using the larval exsheathment inhibition assay (LEIA). Extracts were prepared from leaves of either plant species using 70% ethanol (E70), 100% ethanol (E100), or boiling water (W). Larvae were incubated in a phosphate-buffered saline solution with or without plant extract (1200µg/ml) and then exposed to an exsheathment solution expected to elicit 100% exsheathment after one hour. All extraction methods of P. lentiscus were highly effective at inhibiting larval exsheathment, but higher potency was found for the E70 than for E100 extraction method, while W was intermediate. Only the E70 extract of P. latifolia was highly effective relative to the control. The E70 extract of P. lentiscus had more than 7 times the potency of the E70 extract of P. latifolia. Irrespective of solvent and tannin-equivalent used, P. lentiscus contained more than double the quantity of total polyphenols than P. latifolia. The polyphenols of P. lentiscus consisted mainly of galloyl derivatives (63.6%), flavonol glucosides (28.6%), and catechin (7.8%). In P. latifolia, oleuropein and its derivative tyrosol accounted for 49.3 and 23.1% of phenolics, respectively, the remainder being flavones (luteolin and quercetin) and their glucoside derivatives. Results of the LEIA test suggest that extracts of tannin-rich plants interfere with the very early stage of host invasion and that high concentration of galloylated derivatives may explain anthelmintic activity.

Consumption of Pistacia lentiscus foliage alleviates coccidiosis in young goats.

Coccidiosis near weaning is a major cause of diarrhea, ill-thrift, and impaired performance in small ruminants. A recent survey showed that in villages of the Samaria Hills, Israel, shepherds treat young, weaned goat kids afflicted with diarrhea by cutting and feeding them the foliage of Pistacia lentiscus L. (lentisk) or by tethering them close to lentisk bushes which they browse. The aim of the present study was to assess whether lentisk leaves do indeed have anti-coccidial value, and, if positive, to ascertain the role of tannins in this effect. We monitored for 24 (Experiment 1) and 30 (Experiment 2) days the effect of lentisk feeding on the development of naturally occurring coccidiosis in weaned kids artificially infected with parasitic nematodes. In Experiment 1, kids were infected with nematodes and fed lentisk foliage (PIS) or cereal hay (HAY). Coccidiosis developed at the early stage of the nematode infection, when dietary treatments were initiated. Kids in the PIS group had a lower (P<0.02) concentration of oocysts per gram feces (opg). In Experiment 2, aimed at verifying if tannins are the active component in lentisk foliage, coccidiosis occurred at the peak of the nematode infection, before experimental diets were initiated. Dietary treatments were: cereal hay (HAY), or lentisk foliage consumed without (PIS) or with (PISPEG) a 20-g daily supplement of polyethylene glycol (PEG; MW 4000), a molecule that impairs tannin-bonding with proteins. Goats fed the PIS diet had lower fecal opg counts than counterparts of the HAY (P<0.001) and PISPEG (P<0.002) treatments. Fecal opg counts for the HAY and PISPEG treatments did not differ, suggesting that the anti-coccidial moiety in lentisk was indeed tannins. Our results strongly suggest that: (i) in agreement with the ethno-veterinary anecdotal evidence, exposure of young, weaned goat kids to lentisk foliage alleviates coccidiosis; and (ii) this positive effect is associated with tannins. As coccidiosis is a major affliction of kids, providing them with tannin-rich browse near weaning could be an environmentally friendly way of improving their welfare and health status, in particular under bio-organic farm management.

Anthelmintic activity of Pistacia lentiscus foliage in two Middle Eastern breeds of goats differing in their propensity to consume tannin-rich browse.

The Damascus and Mamber breeds of goats thrive in Middle Eastern Mediterranean regions where the tannin-rich (20% of polyethylene glycol-binding tannins) brush species Pistacia lentiscus L. (lentisk) is ubiquitous. In light of the increasing recognition of the anthelmintic activity of plant tannins, we examined the effect of offering lentisk foliage for 24 days on fecal egg excretion in 5.5-month-old Damascus and Mamber kid goats (n=28) following infection with 10,000 L3 larvae of mixed gastro-intestinal nematodes (GIN). Lentisk foliage was consumed with or without a daily supplement of 20 g polyethylene glycol (PEG; MW 4000). Lentisk tannins showed a strong protein-depletive effect that was totally reversed by the addition of PEG. At the peak of infection, kids of the two breeds lost weight unless they were fed with lentisk without PEG. Fecal egg counts (FEC) were lowest - and did not differ from 0 - in kids fed lentisk without PEG, highest in the controls fed hay as roughage, and intermediate in kids fed lentisk and PEG (241, 1293, and 705 eggs per gram, respectively, SEM 180; P<0.001); therefore, the anthelmintic activity of lentisk was only partly attributable to tannins. The suppressive effect of lentisk on FEC ceased when feeding was discontinued, suggesting that female parasites were not killed but their fertility was reversibly impaired. Damascus kids showed lower FEC than their Mamber counterparts, inferring that the effect of foraging on tannin-rich species is only additive to genetic differences between goat breeds in their sensitivity to GIN infection. On the basis of our results we would expect yearlong lentisk grazing to result in no or very low GIN infection, and Damascus goats to have some advantage over Mamber goats where chemical control of GIN is unfeasible. There appears to be a trade-off between the benefits of lentisk tannin as drug and its side-effects (protein depletion) when given at high level; how goats balance this trade-off requires further elucidation.

Energy cost of activities and locomotion of grazing cows: a repeated study in larger plots.

We determined the energy costs associated with the activities of beef cows grazing on Mediterranean foothill rangeland covered with herbaceous vegetation. Our central aim was to compare the energy cost coefficients obtained in this study, using relatively large plots, with those obtained in a previous study conducted on smaller plots. Measurements were performed in 3 seasons: in March on nursing cows grazing a 135-ha plot of high quality herbage (11.4 MJ/kg of ME), and in May and September on nonlactating cows grazing a 78-ha plot of low quality herbage (6.2 MJ/kg of ME). Poultry litter manure was given as a supplement in September. Stocking rates on the respective plots were 2.25 and 1.95 ha/cow; 5, 5, and 7 cows were monitored in the respective months. Heat production was determined by continuous monitoring of the heart rate and measurement of the oxygen consumption per heartbeat. Animal location was tracked with global positioning system (GPS) collars equipped with motion sensors. Activity was determined for 5-min intervals using suitable calibration equations. Horizontal and vertical distances traveled were computed by integrating GPS data and plot maps in a geographic information system. Three models were used to estimate the energy cost coefficients of engaging in a given activity and locomotion. Total daily heat production ranged from 644 (September) to 1,014 kJ.kg of BW(-0.75).d(-1) (March; P = 0.04). Estimates of the energy cost coefficients for activity states (kJ.kg of BW(-0.75).d(-1)) ranged from 42.7 to 46.2 for standing, from 84.5 to 92.4 for walking idle, and from 89.4 to 103.2 for grazing; those for locomotion (kJ.kg of BW(-0.75).d(-1).km(-1)) ranged from 2.8 to 2.9 for horizontal locomotion and from 21.4 to 27.9 for vertical locomotion. Estimated cost coefficients of standing, grazing, and horizontal locomotion derived in the present study from animals on relatively larger plots were similar to those of the previous study based on data from smaller plots, but the energy costs of walking idle and of vertical locomotion were greater in the present study than in the previous one. The differences found are associated with the fact that cows in the present study walked for longer periods of time and traveled longer distances in single uninterrupted bouts of locomotion than those in the previous study.

A fecal near-infrared reflectance spectroscopy-aided methodology to determine goat dietary composition in a Mediterranean shrubland.

An ecologically sound approach to the problem of brush encroachment onto Israeli rangeland might be their utilization by goats, but better knowledge of the feeding selectivity and ability of goats to thrive in encroached areas is required to devise viable production systems. Direct observation of bites could provide precise and accurate estimates of diet selection, but construction of a sufficiently large database would require too much time. The present study describes the first attempt to construct fecal near-infrared reflectance spectroscopy (NIRS) calibrations of the botanical and nutritional composition of the diet, and of the total intake of free-ranging goats, based on reference values determined with bite-count procedures. Calibration of fecal NIRS was based on 43 observations encompassing 3 goat breeds and 4 periods (spring, summer, and fall of 2004, and spring of 2005). Each observation comprised 242 min of continuous recording of the species and bite-type category selected by a single animal, on each of 2 consecutive days. The mass and chemical quality of each species and bite-type category-a total of more than 200,000 bites-were determined by using the simulated bite technique. Associated feces were scanned in the 1,100- to 2,500-nm range with a reflectance monochromator. Fecal NIRS calibrations had reasonable precision for dietary percentages of the 3 main botanical components: herbaceous vegetation (as one category; R(2) = 0.85), Phillyrea latifolia (R(2) = 0.89), and tannin-rich Pistacia lentiscus (R(2) = 0.77), with SE of cross-validation (SECV) of 7.8, 6.3, and 5.6% of DM, respectively. The R(2) values for dietary percentages of CP, NDF, IVDMD, and polyethylene glycol-binding tannins were 0.93, 0.88, 0.91, and 0.74, respectively, with SECV values of 0.9, 2.1, 4.3, and 0.9% of DM, respectively. The R(2) values for intakes of herbaceous vegetation, P. latifolia, and P. lentiscus were 0.80, 0.75, and 0.65, with SECV values of 71, 64, and 46 g of DM/d, respectively. The R(2) values for the daily nutrient intakes were below 0.60. Fecal NIRS data can be used to expand the databases of botanical and nutritional dietary composition when observed and resident animals graze simultaneously, but intakes should be calculated from fecal NIRS-predicted dietary DM composition and an independent evaluation of DMI.

Energy cost of cows' grazing activity: Use of the heart rate method and the Global Positioning System for direct field estimation.

This study with grazing beef cows on the range was designed to explore the possibility of determining incremental energy expenditure (EE) in standing, traveling, and grazing relative to that in lying down, by means of continuous monitoring of EE, location, and activity by the heart-rate method, with Global Positioning System (GPS) collars, and by motion sensors in the GPS collars, respectively. Cows were observed on Mediterranean foothill rangeland covered with herbaceous vegetation through 4 seasons of the year. There were 2 stocking rate treatments, and 14 statistical models were evaluated, including one that was a stepwise model. Total daily EE (TEE) was affected by many interdependent factors apart from activity, including season, stocking rate, herbage quality, standing biomass, and reproductive state of the cow. Each model included all activity variables, plus some of the other factors. Across seasons and treatments TEE, in kJ/(kg of BW(0.75) . d), ranged from 469 in densely stocked, nonlactating cows in June to 1,092 in sparsely stocked, lactating cows in April. The cows' daily vertical and horizontal movements ranged from 75 to 174 m and from 1.5 to 4.2 km, respectively. Within a day, time spent traveling (without grazing) ranged from 0 to 32 min, and grazing time ranged from 4.4 to 12.1 h. Cows spent less time grazing (P < 0.001) in the summer, when herbage quality was low, than in winter and spring. Relative to the baseline EE while lying down, the daily increment incurred by grazing ranged from 13 to 48 kJ/(kg of BW(0.75) . d), and that incurred by grazing, standing, and traveling combined ranged from 38 to 74 kJ/(kg of BW(0.75) . d) or 5.8 to 11.4% of TEE. In conclusion, the estimates of activity costs yielded by 11 of the models were similar to one another, whereas those yielded by the stepwise model and the remaining 2 models were 20% smaller. The cost of grazing activity was estimated to be 6.14 J/(kg of BW(0.75) . m), and that of locomotion during grazing was 6.07 J/(kg of BW(0.75) . m), which agree with values obtained for animals and humans by means of a treadmill. The experimental and statistical approach tested here yielded fairly reliable estimations of energy costs of activities in grazing cows.