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Measuring foraging behaviour and pasture intake of ruminants is useful but difficult. Acoustic monitoring is one of the most promising methods for this task. In this work, we test its potential to classify jaw movements (JM) according to type (bite, chew, chew-bite), activity (grazing or rumination), and forage species being consumed. Experiments with cows and sheep grazing and ruminating several forages were conducted. First, each JM was manually identified, classified and described by two sets of sound features: i) one containing energy bands of the spectrum (EB), and ii) one containing four complementary (or global) variables (Cv). Two models were evaluated, one with EB alone and the other one combining EB and Cv. Jaw movements were correctly classified by type with 73.0% and 78.5% average accuracy. Accuracy wasbetter for cows than sheep (85 vs 66%). Simultaneous identification of the type of JM and plant species was about 78%. Classification accuracy of activity based on chews averaged 68.5% and 77.0% for rumination and grazing. Models including global variables performed better than using only the spectrum. Acoustic monitoring is a very promising method for further development, particularly to study diet selection. Fil: Galli, Julio Ricardo. Universidad Nacional de Rosario; Argentina Fil: Milone, Diego Humberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigación en Señales, Sistemas e Inteligencia Computacional. Universidad Nacional del Litoral. Facultad de Ingeniería y Ciencias Hídricas. Instituto de Investigación en Señales, Sistemas e Inteligencia Computacional; Argentina Fil: Cangiano, Carlos Alberto. Instituto Nacional de Tecnologia Agropecuaria. Centro Regional Buenos Aires Sur.; Argentina Fil: Martínez, César Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigación en Señales, Sistemas e Inteligencia Computacional. Universidad Nacional del Litoral. Facultad de Ingeniería y Ciencias Hídricas. Instituto de Investigación en Señales, Sistemas e Inteligencia Computacional; Argentina Fil: Lacambra, Emilio. University of California at Davis; Estados Unidos Fil: Chelotti, Jose Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigación en Señales, Sistemas e Inteligencia Computacional. Universidad Nacional del Litoral. Facultad de Ingeniería y Ciencias Hídricas. Instituto de Investigación en Señales, Sistemas e Inteligencia Computacional; Argentina Fil: Rufiner, Hugo Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigación en Señales, Sistemas e Inteligencia Computacional. Universidad Nacional del Litoral. Facultad de Ingeniería y Ciencias Hídricas. Instituto de Investigación en Señales, Sistemas e Inteligencia Computacional; Argentina

Accurate measurement of herbage intake rate is critical to advance knowledge of the ecology of grazing ruminants. This experiment tested the integration of behavioral and acoustic measurements of chewing and biting to estimate herbage dry matter intake (DMI) in dairy cows offered micro-swards of contrasting plant structure. Micro-swards constructed with plastic pots were offered to three lactating Holstein cows (608±24.9 kg of BW) in individual grazing sessions (n=48). Treatments were a factorial combination of two forage species (alfalfa and fescue) and two plant heights (tall=25±3.8 cm and short=12±1.9 cm) and were offered on a gradient of increasing herbage mass (10 to 30 pots) and number of bites (~10 to 40 bites). During each grazing session, sounds of biting and chewing were recorded with a wireless microphone placed on the cows? foreheads and a digital video camera to allow synchronized audio and video recordings. Dry matter intake rate was higher in tall alfalfa than in the other three treatments (32±1.6 v. 19±1.2 g/min). A high proportion of jaw movements in every grazing session (23 to 36%) were compound jaw movements (chew-bites) that appeared to be a key component of chewing and biting efficiency and of the ability of cows to regulate intake rate. Dry matter intake was accurately predicted based on easily observable behavioral and acoustic variables. Chewing sound energy measured as energy flux density (EFD) was linearly related to DMI, with 74% of EFD variation explained by DMI. Total chewing EFD, number of chew-bites and plant height (tall v. short) were the most important predictors of DMI. The best model explained 91% of the variation in DMI with a coefficient of variation of 17%. Ingestive sounds integrate valuable information to remotely monitor feeding behavior and predict DMI in grazing cows. Fil: Galli, Julio Ricardo. Universidad Nacional de Rosario; Argentina Fil: Cangiano, Carlos Alberto. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires; Argentina Fil: Pece, M. A.. Universidad Nacional de Rosario; Argentina Fil: Larripa, M. J.. Universidad Nacional de Rosario; Argentina Fil: Milone, Diego Humberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigación en Señales, Sistemas e Inteligencia Computacional. Universidad Nacional del Litoral. Facultad de Ingeniería y Ciencias Hídricas. Instituto de Investigación en Señales, Sistemas e Inteligencia Computacional; Argentina Fil: Utsumi, S. A.. Michigan State University; Estados Unidos Fil: Laca, E. A.. University of California at Davis; Estados Unidos

The relationship between herbage intake by herbivores and herbage available depends on the interaction between sward structure and animal behaviour. This relationship is a crucial component determining the stability, function and productivity of grazing systems. The present study aims at quantifying the mechanisms by which intake rate is determined in swards of contrasting structure and forage species, and it reveals the importance of animal choice in the interaction between animal and sward. We hypothesised that as sward height and herbage mass increased, bite mass and intake rate would increase. The relationship between intake rate and bite mass should exhibit a higher asymptote for the more succulent, less fibrous Avena than for Cynodon due to differences in chewing requirements per unit dry mass of intake. In four different experiments, Cynodon sp . cv. Tifton 85 and Avena strigosa cv. Iapar 61 swards of different heights were obtained by various durations of short time high-intensity grazing or by different growth periods. Bite mass and intake rate were estimated by the double-weighing technique with correction for insensible losses. Number and timing of jaw movements and bites were measured with behaviour recorders. Bite mass was the main variable determining intake rate. Contrary to expectations, bite mass first increased and then decreased with increasing sward height, a result that seems due to animal choice and not from restrictions imposed by the swards. As expected, Cynodon sp. swards required more chewing per unit DM intake due to their higher DM content (39.5 vs. 22.6, P P A. strigosa . Harvesting and chewing jaw movements, the components of total jaw movements and time per bite, had different time costs, and values were remarkably similar to previously published values. On average, each harvesting jaw movement took 1s and a chewing jaw movement took 0.68s. The reduction in bite mass with increasing sward height in tall swards is discussed as a destabilising mechanism that generates spatial heterogeneity in sward height and mass.

Information about ingestive events like chewing and biting is useful for estimation of intake and monitoring of grazing behaviour. We present an automatic tool to decode ingestive sounds of cattle into ingestive events. Ingestive sounds can be recorded easily and without alteration of normal grazing behaviour by placing a microphone on the forehead of the animal. However, recorded sound need to be decoded automatically for the method to be of practical use. Hidden Markov models have been successfully used to segment and classify acoustic signals. In this work we extend the use of hidden Markov models to recognise ingestive sounds of cattle. We present new findings about the spectral content of the acoustic signals and a novel language model for the recognizer. Three types of ingestive events (bites, chews and chewbites) by cows grazing tall (24.5+/-3.8cm) or short (11.6+/-1.9cm) alfalfa or fescue were successfully recognised. Recognition rates were 84% for tall alfalfa, 65% for short alfalfa, 85% for tall fescue and 84% for short fescue. These levels of correct classification are suitable for quantification of grazing behaviour.

The productivity and survival of alfalfa (Medicago sativa L.) is strongly influenced by cutting frequency (CF), but there is a lack of knowledge of how cultivar differences in fall dormancy (FD) respond to CF. The yield components of alfalfa also are affected by CF, but it remains unclear which of the components are most affected and if this effect is similar between cultivars differing in FD. Our objectives were: (i) to evaluate the FD × CF interaction on alfalfa productivity (forage yield and yield components), and (ii) to determine relative importance of yield components in response to CF and FD. Treatments were a factorial combination of three alfalfa cultivars with different FD (3, 6 and 10) and three CF (20, 30 and 40 days intervals). Cultivars were sown on August 24, 2006 in rows 30-m long and 0.5-m apart in a randomized complete block with three replicates. The experimental period was two years where cutting frequencies were applied during 120 days of each year. At the end of each regrowth, forage yield, shoots m−2, mass shoot−1, height shoot−1, mass of shoots per centimeter and stage of maturity by the mean stage count (MSC) were measured. In both years, the FD × CF interaction on forage yield was not significant. Of the two factors used in this experiment, FD and CF, the latter had a greater effect on alfalfa performance reducing forage yield, yield components and survival at the 20-day CF. FD treatment had no effect on two-year total forage yield and alfalfa survival. Plants in the CF 20 treatment always had lower MSC than CF 40 and CF 30 treatments and FD 3 plants were always less mature at cutting than FD 6 and FD 10 plants. Our study provides evidence that: (i) in temperate areas, cutting management recommendations can be advocated for short-term stands of dormant, semidormant and nondormant cultivars alike; and (ii) the choice of cutting frequency by the farmer compared to the choice of FD is more important on productivity and survival of alfalfa. Shoot height−1 was the yield component that had the most impact on forage yield; therefore management practices, genetic improvements, and environment conditions that increase this yield component could improvement alfalfa productivity.

In this work we propose a novel method to analyze and recognize automatically sound signals of chewing and biting. For the automatic segmentation and classification of acoustical ingestive behaviour of sheep the method use an appropriate acoustic representation and statistical modelling based on hidden Markov models. We analyzed 1813 seconds of chewing data from four sheep eating two different forages typically found in grazing production systems, orchardgrass and alfalfa, each at two sward heights. Because identification of species consumed when in mixed swards is a key issue in grazing science, we tested the possibility to discriminate species and sward height by using the proposed approach. Signals were correctly classified by forage and sward height in 67% of the cases, whereas forage was correctly identified 84% of the time. The results showed an overall performance of 82% for the recognition of chewing events. Fil: Milone, Diego Humberto. Universidad Nacional del Litoral. Facultad de Ingeniería y Ciencias Hídricas. Departamento de Informática. Laboratorio de Investigaciones en Señales e Inteligencia Computacional; Argentina Fil: Rufiner, Hugo Leonardo. Universidad Nacional de Entre Ríos. Facultad de Ingeniería; Argentina Fil: Galli, Julio Ricardo. Universidad Nacional del Litoral. Facultad de Ingeniería y Ciencias Hídricas. Departamento de Informática. Laboratorio de Investigaciones en Señales e Inteligencia Computacional; Argentina Fil: Laca, E.A.. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias; Argentina Fil: Cangiano, Carlos Alberto. University of California; Estados Unidos

The effect of different levels of daily allowance and supplementation on intake, milk production and composition and per hectare productivity was studied. Pasture consisted of an association of alfalfa (Medicago sativa), tall fescue (Festuca arundinacea) and prairie grass (Bromus wildenowii) and high moisture corn was used as supplement. 32 cows were allocated to four levels of pasture allowance (NA) and two levels of energy supplementation (SE). Pasture intake and individual and per hectare production were affected by NA, but SE had no signifi cant effect. No interactions were detected between any of the variables. Milk composition were not affected by NA, whereas only non fat solids were affected by SE. Liveweight change and condition score did not show differences among treatments. Urea level in both, plasma and milk, was not affected by NA, whereas the level of urea in plasma showed a trend to be different and the level of urea in milk was signifi cantly different for SE. Critical levels of pasture allowance which directly affect the productivity per hectare, need to be reached in order to perform a signifi cant increase of individual production. Milk fat and protein concentration did not appear to be responsive variables to different levels of supplementation and allowance, whereas the little variation in urea levels, as a response to a greater level of supplementation, did not make this a valuable tool to improve the milk protein constituents. Se estudio el efecto que distintos niveles de asignacion diaria y suplementacion producen sobre el consumo, la produccion y composicion de la leche y la productividad por hectarea. La pastura utilizada fue una asociacion de alfalfa (Medicago sativa), festuca (Festuca arundinacea) y cebadilla criolla (Bromus wildenowii) y el suplemento fue grano de maiz humedo. Se utilizaron 32 vacas y se establecieron cuatro niveles de asignacion de pastura (NA) y dos niveles de suplementacion energetica (SE). El consumo de pastura y la produccion individual y por hectarea fueron afectados por NA y no por SE. Al igual que para el resto de las variables, no se detectaron interacciones entre NA y SE. La composicion de la leche no fue afectada por NA, mientras que SE solo tuvo efecto sobre los solidos no grasos. La evolucion del peso vivo y del estado corporal no mostraron diferencias entre tratamientos. Los niveles de urea en plasma y leche no difi rieron signifi cativamente para NA, no ocurriendo lo mismo para SE, donde el nivel de urea en plasma tendio a diferir y el nivel de urea en leche difi rio signifi cativamente. Se concluyo que para conseguir aumentos signifi cativos en la produccion individual es necesario ofrecer niveles de asignacion que afectan negativamente la produccion por hectarea. La concentracion de grasa y proteina de la leche no parecieron ser variables sensibles a distintos niveles de suplementacion y asignacion, mientras que la escasa variacion en los niveles de urea, debida al mayor nivel de suplementacion, relativizo el valor de esta herramienta para mejorar la composicion de la proteina lactea.

The goal was to evaluate acoustic analysis as a means to monitor and quantify chewing behaviour, and to estimate DM intake of forages with a wide range of water and fibre content. Each of three Angus steers (284–316 kg of body weight) was fed 32 treatments resulting from the factorial combination of four amounts ( i.e. 75, 150, 225 and 300 g dry matter, DM), two particle lengths ( i.e. chopped or whole), two water contents ( i.e. fresh or hay), and two species ( i.e. grass or alfalfa). Behaviour was videotaped and chewing sound was recorded using a microphone attached to the steers foreheads. Intake rate of DM was higher for alfalfa versus grass higher (33.0 ± 2.03 versus 28.7 ± 2.04 g DM/min), and lower in fresh forages versus hays (28.0 ± 2.04 versus 33.7 ± 2.04 g DM/min). Fresh forage was chewed more than hay (3.1 ± 0.19 versus 2.4 ± 0.19 chews/g DM) demonstrating that chewing was primarily affected by water content of forage. Alfalfa hay was chewed less than grass hay, but fresh grass and fresh alfalfa did not differ from each other and required more chewing than fresh forages. The impact of forage internal water in chewing was clear, since chews per g of neutral detergent fibre (NDF) differed among the forages, but for fresh alfalfa (the forage with the most water and the least NDF), it was much higher than for the rest. There was little evidence of an impact of particle size on chewing behaviour, probably because all forages had very long particles. Of the variation of energy in chewing sound (E), 66% was explained by DM intake (DMI). The relationship between E and DMI was linear, and the slope was 28% higher for fresh forages versus hays (P=0.033). Volume of chewing sound explained the most variation in E/DMI, and it was higher for fresh forage versus hays, whereas chews/DMI was the component of E/DMI most affected by forage characteristics. The DMI was estimated accurately based on easily observable behavioural and acoustic variables. Number of chews, cumulative sound energy and forage moisture ( i.e. fresh versus hay) were the most important predictors. The prediction error in cross-validation was 27.3 g DM (coefficient of variation = 16%, R 2 = 0.89). Acoustic analysis yields more useful information than simple the number and rate of chewing, and should be further developed as method to research and monitor chewing behaviour of ruminants.

Acoustic monitoring of the ingestive behavior of grazing sheep was used to study the determinants of intake rate and to estimate dry matter intake (DMI) based on biting and chewing sounds. Each of three crossbred ewes (85±6.0kg body weight) were tested in 16 treatments resulting from the factorial combination of two forage species (orchardgrass and alfalfa), two levels of biomass depletion (tall=30±0.79cm and short=14±0.79cm) and four numbers of bites (20, 40, 60 and 80 bites). During each grazing session biting and chewing sounds were recorded with a wireless microphone placed on the ewe's forehead and connected to a digital video camera for synchronized audio and video recording of ingestive behavior. Dry matter (DM) intake rate was higher for alfalfa than orchardgrass (9.4±0.64 vs. 7.8±0.58g/min, P0.05), because sheep increased biting rate (from 17±1.6 to 28±1.6 bites/min, P

Ecology Letters (2010) 13: 311–320 Abstract Herbivores forage in spatially complex habitats. Due to allometry and scale-dependent foraging, herbivores are hypothesized to perceive and respond to heterogeneity of resources at scales relative to their body sizes. This hypothesis has not been manipulatively tested for animals with only moderate differences in body size and similar food niches. We compared short-term spatial foraging behavior of two herbivores (sheep and cattle) with similar dietary niche but differing body size. Although intake rates scaled allometrically with body mass (mass0.75), spatial foraging strategies substantially differed, with cattle exhibiting a coarser-grained use of the ‘foodscape.’ Selectivity by cattle (and not sheep) for their preferred food was more restricted when patches were smaller (

Background Understanding the mechanisms that influence grazing selectivity in patchy environments is vital to promote sustainable production and conservation of cultivated and natural grasslands. To better understand how patch size and spatial dynamics influence selectivity in cattle, we examined grazing selectivity under 9 different treatments by offering alfalfa and fescue in patches of 3 sizes spaced with 1, 4, and 8 m between patches along an alley. We hypothesized that (1) selectivity is driven by preference for the forage species that maximizes forage intake over feeding scales ranging from single bites to patches along grazing paths, (2) that increasing patch size enhances selectivity for the preferred species, and that (3) increasing distances between patches restricts selectivity because of the aggregation of scale-specific behaviours across foraging scales. Results Cows preferred and selected alfalfa, the species that yielded greater short-term intake rates (P < 0.0001) and greater daily intake potential. Selectivity was not affected by patch arrangement, but it was scale dependent. Selectivity tended to emerge at the scale of feeding stations and became strongly significant at the bite scale, because of differences in bite mass between plant species. Greater distance between patches resulted in longer patch residence time and faster speed of travel but lower overall intake rate, consistent with maximization of intake rate. Larger patches resulted in greater residence time and higher intake rate. Conclusion We conclude that patch size and spacing affect components of intake rate and, to a lesser extent, the selectivity of livestock at lower hierarchies of the grazing process, particularly by enticing livestock to make more even use of the available species as patches are spaced further apart. Thus, modifications in the spatial pattern of plant patches along with reductions in the temporal and spatial allocation of grazing may offer opportunities to improve uniformity of grazing by livestock and help sustain biodiversity and stability of plant communities.