Non-feeding Activities Research Articles

Cetacean tongue mobility and function: A comparative review.

Cetaceans are atypical mammals whose tongues often depart from the typical (basal) mammalian condition in structure, mobility, and function. Their tongues are dynamic, innovative multipurpose tools that include the world's largest muscular structures. These changes reflect the evolutionary history of cetaceans' secondary adaptation to a fully aquatic environment. Cetacean tongues play no role in mastication and apparently a greatly reduced role in nursing (mainly channeling milk ingestion), two hallmarks of Mammalia. Cetacean tongues are not involved in drinking, breathing, vocalizing, and other non-feeding activities; they evidently play no or little role in taste reception. Although cetaceans do not masticate or otherwise process food, their tongues retain key roles in food ingestion, transport, securing/positioning, and swallowing, though by different means than most mammals. This is due to cetaceans' aquatic habitat, which in turn altered their anatomy (e.g., the intranarial larynx and consequent soft palate alteration). Odontocetes ingest prey via raptorial biting or tongue-generated suction. Odontocete tongues expel water and possibly uncover benthic prey via hydraulic jetting. Mysticete tongues play crucial roles driving ram, suction, or lunge ingestion for filter feeding. The uniquely flaccid rorqual tongue, not a constant volume hydrostat (as in all other mammalian tongues), invaginates into a balloon-like pouch to temporarily hold engulfed water. Mysticete tongues also create hydrodynamic flow regimes and hydraulic forces for baleen filtration, and possibly for cleaning baleen. Cetacean tongues lost or modified much of the mobility and function of generic mammal tongues, but took on noteworthy morphological changes by evolving to accomplish new tasks.

Browse or browsing: Investigating goat preferences for feeding posture, feeding height and feed type.

Goats naturally browse different forages in various postures; this differs from typical farm practice, thus there are opportunities to improve goat welfare by understanding what and how they like to eat. We investigated if feeding preference was related to posture, feeder height relative to the ground, and type of feed. Sixteen adult, Saanen cross females participated in two experiments comparing a floor-level feeder (grazing posture; farm standard), with an elevated feeder (browsing posture; Exp1) and a platform-level feeder (raised, grazing posture; Exp2), when two forages (leaves, grass) were offered. Measurements included feed intake (g of DM/feeder), feeder switching frequency, first feeder visited, latency to visit first feeder and exploration and non-feeding activity time. Effects of posture (Exp1), height (Exp2) and feed type were analyzed. Type of feed affected preference for feeding posture and height. All goats consumed leaves over grass (Exp1: POP: 188 ± 6.52 g, GRA: 20.3 ± 7.19 g; Exp2: POP: 191 ± 6.15 g, GRA: 0.231 ± 6.91 g; P < 0.001), and the feeder containing leaves was often visited first (Exp 1: GRA/POP: 94% of visits, P < 0.001, POP/GRA: 53%, P = 0.724; Exp 2: GRA/POP: 91%, P < 0.001; POP/GRA: 69%, P = 0.041). When goats received only leaves, they consumed more from the floor-level (162 ± 22.2 g) vs. elevated level (102 ± 21.9 g) feeder (P = 0.039). When goats received only grass, there was no posture or height preference; however, they changed feeders more frequently (at least 4x (Exp1) and 2x (Exp2) more than other combinations; P > 0.01). Feed intake was negatively affected by exploring time (Exp1 only: r = -0.541; P < 0.001) and performing non-feeding activities (Exp1: r = -0.698; P < 0.001; Exp2: r = -0.673; P < 0.001). We did not identify a preference for elevated feeding posture; however, we suggest that our short test (compared to previous work) encouraged goats to make choices based on line-of-sight and also that the elevated feeder design (replicated from previous work) made leaf access harder. Nonetheless, we highlight that some goats actively used the elevated feeder; this coupled with the clear preference for leaves over grass, suggests that offering feed type and presentation diversity would allow individuals to express their natural feeding behavior more fully.

Grazing behaviour, intake, digestion, performance and endoparasitic infection of lambs raised at different stocking rates under low-input farming systems

Twenty-four Boutsiko breed lambs were allocated to three groups of equal average live weight (LW: 20.8 kg) and pastured at three stocking rates: SR1, SR2 and SR3 (representing 60, 80 and 100 lambs/ha respectively) under low-input farming practices. Animals were grazed on a semi natural sward daily, during a 60 days period. Sward height in all treatments remained above 7 cm during the trial and the herbage gross chemical composition was similar between treatments. On average, the lambs grazed 372 min, ruminated 140 min and spent 88 min on other non-feeding activities during the daily pasturing. Lambs consumed at the start and the finish of the trial 714 g and 1014 g of herbage DM/day, or 70.5 and 99.0 g/kgW0.75/day respectively. Herbage DM digestibility (in vivo) was moderate averaging 61% and no differences were observed between the three groups of lambs. The daily live weight gain of lambs (DLWG) was different (p&lt;0.01) between the stocking rates, where lambs on plot SR1 had the highest gain (0.0918 kg LW/day) and lambs on SR2 and SR3 plots the lowest gain (0.0344 and 0.0531 kg LW/day respectively). Faecal egg counts (FEC) for gastrointestinal parasites (GIN) from lambs grazing plot SR3 were low, while high numbers of Moniezia spp. eggs were present in faecal samples of all groups of lambs at the end of the experiment. It is concluded that lamb fattening on pasture can be achieved at reasonable stocking rates, without the use of anthelmintics, if a local hardy breed is used.

Larder Hoarding Versus Immediate in situ Food Consumption in Two Fiddler Crab Species: Is it an Evolutionarily Stable Strategy?

Larder hoarding behavior in central place foragers has been widely studied in vertebrates, albeit, not as extensively as scatter hoarding. However, scant information is available for the invertebrate taxa, especially aquatic species. We investigated this phenomenon via an in situ food supplementation experiment in a community of two sympatric fiddler crabs, Austruca annulipes (n = 80; 40 males and 40 females) and Gelasimus vocans (n = 60; 30 males and 30 females), in a Singapore mangrove patch with an intermediate resource level. As the semiterrestrial intertidal crabs can only forage after emergence from their burrows during exposure period, the duration of time available for feeding is finite and constitutes an important constraint in the optimization of food intake. The activity budget (in terms of time spent on feeding activities, all above-ground non-feeding activities, and burrow-sequestration) as well as the occurrence (if any) of larder hoarding behavior in these two species after they first emerged were recorded by hourly intervals (three hours of observation) to determine the effect of time left for foraging on larder hoarding. Regardless of species, A. annulipes and G. vocans spent most of the time feeding when the tide was out, despite overall significant behavioral heterogeneity (multivariate analyses using ANOSIM) indicating that both species prioritized hunger satiation over other activities. Our results also showed that although the two sympatric crabs live in the same mangrove area with similar food resource levels, only A. annulipes larder hoarded. The propensity to larder hoard did not differ significantly between the sexes, nor among the three time periods of the feeding duration. Gelasimus vocans, one of the species of crabs known to form feeding droves, did not larder hoard at all. We propose that A. annulipes is a species that can deploy larder hoarding as a foraging strategy when it encounters valuable food resources, and such a strategy is highly advantageous for the species as it generally inhabits sandy habitats that are poor in nutrient levels. Hence, larder hoarding can be considered a mixed evolutionarily stable strategy (ESS) adopted by A. annulipes. In contrast, G. vocans that commonly inhabits muddy sediments-with a high level of food resources-did not larder hoard, even when provided with supplemented food, suggesting perhaps that its mixed ESS is droving behavior.

Plant defense responses triggered by phytoseiid predatory mites (Mesostigmata: Phytoseiidae) are species-specific, depend on plant genotype and may not be related to direct plant feeding

Zoophytophagous arthropods can elicit plant defense responses affecting potential prey beyond predation. Phytophagy prevails as the main trigger for these responses, as in the case of Euseius stipulatus (Athias-Henriot) (Mesostigmata: Phytoseiidae), a predator occurring in citrus. Because other triggers cannot be excluded, our aim was to examine whether other phytoseiids co-occurring with E. stipulatus but not engaged in plant feeding [Neoseiulus californicus (McGregor) and Phytoseiulus persimilis Athias-Henriot] could induce similar responses (in terms of herbivore induced plant volatiles, HIPVs, and main defensive pathways), and how these affected the behavior of conspecifics and the shared prey, Tetranychus urticae Koch (Prostigmata: Tetranychidae). N. californicus triggered plant genotype-specific defense responses, including the production of different HIPVs compared to clean plants. However, we could not observe these effects for P. persimilis. T. urticae avoided better protected plants, because of stronger direct or indirect defense. As plants with weaker direct defense levels should offer higher prey densities, and those harboring conspecific predators represent higher risk of cannibalism, predators were expected to behave similarly. However, they did not. Our results demonstrate that plant defense triggered by phytoseiids is species-specific, depend on plant genotype and can be triggered by non-feeding activities. As N. californicus is a highly efficient predator used worldwide, further studies with this species are needed. Likewise, cineol, one of the volatiles identified in the blends triggered by this phytoseiid, could be used to manipulate the prey. These studies could pave the way for a more efficient use of phytoseiids in agroecosystems.

Male social rank and food competition in a primate multi-level society.

Social animals often have dominance hierarchies, with high rank conferring preferential access to resources. In primates, competition among males is often assumed to occur predominantly over reproductive opportunities. However, competition for food may occur during food shortages, such as in temperate species during winter. Higher-ranked males may thus gain preferential access to high-profitability food, which would enable them to spend longer engaged in activities other than feeding. We performed a field experiment with a breeding band of golden snub-nosed monkeys, a species that lives in a multi-level society in high-altitude forests in central China. We provisioned monkey's high-profitability food during winter when natural foods are limited, and then recorded the times individual adult males spent engaged in different behaviors. Higher-ranking males spent less time feeding overall and fed on provisioned foods at a higher rate than lower-ranking males. Higher-ranking males therefore had more time to spend on alternative behaviors. We found no significant difference according to rank in times spent moving or resting. However, high-ranking males spend significantly longer on affiliative behaviors with other members of their social sub-units, especially grooming and being groomed, behaviors known to promote social cohesion in primates. We show that preferential access to high-profitability foods likely relaxes time-budget constraints to higher-ranking males. High-ranking males thus spend more time on non-feeding activities, especially grooming, which may enhance social cohesion within their social sub-unit. We discuss the potential direct and indirect benefits to high-ranking males associated with preferential access to high-value food during winter.

Terrestrial threats dominate the waterbird landscape of fear in a savannah pan wetland system

Natural or anthropogenic disturbances (stimuli that trigger a behavioural response from animals) can have direct consequences on fitness and population trends. This study aimed at investigating the relative influence of three types of disturbances (mammalian herbivores, terrestrial threats from ground predators and aerial threats) on the responses by waterbirds at waterpans in Hwange National Park (HNP, Zimbabwe) and adjacent land uses. Thirteen waterpans were monitored during daylight hours between years 2015 and 2017 and responses of waterbirds to the three forms of disturbances were recorded. Logistic regressions revealed that the likelihood of responding was highest after terrestrial threats; with individuals/groups that were initially engaged in non-feeding activities that allowed vigilance, responding the most. Wildfowl species spent significantly longer time flying (compared to waders and generalists), more so in communal areas (CAs) than HNP, and after terrestrial threats compared to aerial threats and herbivore disturbances. We did not find any differences in probability of responding across land uses probably because there is less human disturbance in HNP, but predation risk is high. Further, even though there are less terrestrial predators in CAs, domestic dogs may be maintaining the stimuli. We conclude that terrestrial threats are least tolerated, with species most susceptible to human predation (i.e. wildfowl) losing more time avoiding them. Interestingly, only acute aerial threats induced departure from waterpans. Our findings have a direct implication for waterbird conservation as herbivore and human density in this area are currently increasing.

Body size and competitor identity modulate prey consumption and feeding behaviour in a slow-moving benthic predator (Asterias rubens, Linneaus)

Understanding interactive effects of body size and competition on predator-prey relationships is key to predicting shifts in marine communities, particularly under accelerating pace of introductions of non-native species on a global scale. The common sea star, Asterias rubens (Linneaus), is a dominant indigenous predator in rocky subtidal habitats in eastern Canada, affecting community structure through sustained consumption of bivalve prey, mainly blue mussel, Mytilus edulis (Linneaus). Yet, considerable spatial and dietary overlaps with the indigenous rock crab, Cancer irroratus (Say), and introduced green crab, Carcinus maeneas (Linneaus), together with comparatively lower mobility in A. rubens, suggest the latter is poorly fit to compete with both crabs for M. edulis. A laboratory mesocosm experiment was used to examine competitive interactions for variably-sized M. edulis between small and large, 3-week starved A. rubens, and large C. irroratus or C. maenas (in one-on-one sea star versus crab face-offs) from southeastern Newfoundland. Mussel consumption in starved A. rubens, as well as four components of its natural feeding behaviour, were quantified over 75-h trials in relatively cold (~4 to 5.5 °C) seawater representative of the current northern limit of C. maenas' distribution in the northwestern Atlantic. Results showed that starved A. rubens (1) prioritizes consumption, upon contacting mussel prey, over non-feeding activities such as responding to physical contacts initiated by crabs; (2) alters consumption and feeding behaviour under prolonged exposure to C. irroratus; and (3) increases movement in presence of green crab, more so in large than small sea stars. Overall, findings demonstrate that A. rubens' foraging decisions vary ontogenetically and with competitor's identity. Observed differences in consumption and feeding behaviour in A. rubens exposed to familiar (rock crab) or unfamiliar (green crab) competitors also suggest timing and frequency of encounters with competitors have the potential to alter feeding patterns throughout an organism's lifetime.

Use of Wild Foods During the Rainy Season by a Reintroduced Population of Scarlet Macaws (Ara Macao Cyanoptera) in Palenque, Mexico

The scarlet macaw ( Ara macao cyanoptera) is an endangered species in Mesoamerica due to illegal traffic, habitat loss, and hunting. In Mexico, its range has been reduced by 98%. Between April 2013 and June 2014, a population of 96 individuals of A. m. cyanoptera was reintroduced (six releasing events), in the tropical rainforests of Palenque, southeast Mexico, where this macaw had been extinct for the last 70 years. This study documents the use of wild foods and range use by the reintroduced macaws for the rainy season period June to November, 2014. The macaws used 140 trees of 31 species (19 families; 84% native species) as a source of food. Seeds and fruit accounted for 70% of their diet. The remaining 30% consisted of bark, stems, leaves, insect galls, flowers and shoots. A subset of five tree species was highly dominant in their diet (regarding number of trees used, months used and feeding records). Spatial data showed that food trees used by the macaws were dispersed over 36 ha and had a highly clumped distribution. The macaws used an additional 23ha for non-feeding activities. The dietary diversity and breadth (as indicated by Levin's Index) of the reintroduced macaws closely approaches that of wild macaws. The capacity of the reintroduced macaws to use wild foods, a very low mortality in the released population (9%), and the occurrence of nine successful nesting events, attests to a short-term success of the reintroduction. We discussed the observed patterns of use of wild foods and habitat by the reintroduced scarlet macaws in the context of the soft-release protocol used and of behavioral flexibility, accumulated social learning and a high cognitive capacity typical of psittacines, aspects essential for a successful adaptation to the wild.

Observations on the feeding behaviour of late-instar larvae ofChoristoneura fumiferana

AbstractLaboratory observations revealed that late-instar larvae of the eastern spruce budworm (Choristoneura fumiferana(Clemens)) (Lepidoptera: Tortricidae) spend most of their time spinning, wandering, and resting; less than 10% is spent feeding. Larvae feed in a discontinuous pattern of short feeding bouts separated by much longer intervals of nonfeeding activity. Over a 2 h observation period, feeding bouts averaged 2.2 min and were separated by 17.4 min intervals for 4th-instar larvae as compared to 3.3 min bouts separated by 33.4 min intervals for 5th-instar larvae. The duration of a feeding bout was positively correlated with the duration of the subsequent interval, not with the duration of preceding intervals, suggesting that feeding-bout frequency is governed primarily by post-ingestion processes. It is postulated that short feeding bouts followed by long intervals limit the window for ingesting an efficacious dose of aerially applied insecticides such asBacillus thuringiensis.

Patterns of daily activity of Meyer's Parrot (Poicephalus meyeri) in the Okavango Delta, Botswana

Most parrots from Africa, Australasia and the Neotropics have bimodal patterns of daily activity owing to physiological restrictions (e.g. crop-size) and climatic constraints (e.g. seasonal fluctuations in temperature and rainfall). We monitored the daily patterns of flight, feeding and non-feeding activities of Meyer's Parrots (Poicephalus meyeri) over 24 months at two study sites for correlation with climatic conditions, availability of food, and mean rates of protein and energy acquisition from these food resources. Feeding activity between 0830 and 1100 hours was likely to be obligate, whereas feeding between 1600 and 1830 hours was seasonally needed to achieve daily protein requirements. This weak bimodality was supported by daily nutritional requirements and midday digestive restrictions (e.g. fixed crop-size). Feeding activity patterns of Meyer's Parrots at population level were significantly influenced by high and low temperatures throughout the year. A bimodal pattern of daily flight-activity was, however, a function of communal roosting and dispersal for foraging as central-place foragers. The patterns of daily activity of other parrots that rely on seeds may also be constrained by similar physiological, behavioural and climatic factors. Counting Meyer's Parrots in the late morning, between 0830 and 1100 hours, would yield the highest minimum population estimate for a given area.

A taste of the deep-sea: The roles of gustatory and tactile searching behaviour in the grenadier fish Coryphaenoides armatus

The deep-sea grenadier fishes ( Coryphaenoides spp.) are among the dominant predators and scavengers in the ocean basins that cover much of Earth's surface. Baited camera experiments were used to study the behaviour of these fishes. Despite the apparent advantages of rapidly consuming food, grenadiers attracted to bait spend a large proportion of their time in prolonged periods of non-feeding activity. Video analysis revealed that fish often adopted a head-down swimming attitude (mean of 21.3° between the fish and seafloor), with swimming velocity negatively related to attitude. The fish also swam around and along vertical and horizontal structures of the lander with their head immediately adjacent to the structure. We initially hypothesised that this behaviour was associated with the use of the short chin barbel in foraging. Barbel histology showed numerous taste buds in the skin, and a barbel nerve with about 20,000 axons in adult fish. A tracing experiment in one undamaged animal revealed the termination fields of the barbel neurons in the trigeminal and rhombencephalic regions, indicating both a mechanoreceptory and a gustatory role for the barbel. Our conclusion was that olfactory foraging becomes ineffective at close ranges and is followed by a search phase using tactile and gustatory sensing by the barbel. The development of this sensory method probably co-evolved alongside behavioural changes in swimming mechanics to allow postural stability at low swimming speeds.

Predator avoidance behavior in the pea aphid: costs, frequency, and population consequences

Induced prey defenses can be costly. These costs have the potential to reduce prey survival or reproduction and, therefore, prey population growth. I estimated the potential for predators to suppress populations of pea aphids (Acyrthosiphon pisum) in alfalfa fields through the induction of pea aphid predator avoidance behavior. I quantified (1) the period of non-feeding activity that follows a disturbance event, (2) the effect of frequent disturbance on aphid reproduction, and (3) the frequency at which aphids are disturbed by predators. In combination, these three values predict that the disturbances induced by predators can substantially reduce aphid population growth. This result stems from the high frequency of predator-induced disturbance, and the observation that even brief disturbances reduce aphid reproduction. The potential for predators to suppress prey populations through induction of prey defenses may be strongest in systems where (1) predators frequently induce prey defensive responses, and (2) prey defenses incur acute survival or reproductive costs.

Interspecific Differences in Feeding Behavior and Survival Under Food-Limited Conditions for Larval &lt;I&gt;Aedes albopictus&lt;/I&gt; and &lt;I&gt;Aedes aegypti&lt;/I&gt; (Diptera: Culicidae)

Aedes albopictus has replaced Aedes aegypti in much of the latter species' historic range within the United States. The leading hypothesis for this displacement is exclusion via resource competition; however, the proximate mechanism producing a competitive advantage for A. albopictus over A. aegypti has not been identified. We performed laboratory experiments to test the hypotheses that these species differ in feeding behavior, and that these differences result in differences in survival when resources are scarce. Differences in feeding behavior were assessed in three environments with food (growing microorganisms) available: 1) in fluid only; 2) on leaf surfaces only; 3) or both in fluid and on leaf surfaces. We determined behavior of larvae in these environments, recording their positions (bottom, wall, leaf, top, or middle) and activities (browsing, filtering, resting, or thrashing) using instantaneous scan censuses. A. albopictus spent significantly more time at leaf surfaces, whereas A. aegypti spent more time engaging in nonfeeding activities. Both species showed a significant shift in foraging activity toward leaves when leaves were available. In a second experiment, we recorded survivorship for individuals raised in two treatment combinations: whole or half 17-mm disks of live oak leaves, with or without direct access to the leaf surface (controlled using nylon mesh, which allowed movement of microscopic organisms, but prevented mosquito larva movement between container sides). After 31 d, survivorship of A. albopictus was significantly greater than that of A. aegypti regardless of treatments. Moreover, A. albopictus showed significantly greater survivorship compared with A. aegypti when deprived of access to leaf surfaces and in whole leaf disk treatments, suggesting superior resource-harvesting ability for A. albopictus. Our experiments suggest that differences in foraging behavior contribute to the competitive advantage of A. albopictus over A. aegypti that has been observed in North America.

Tomato psyllid behavioral responses to tomato plant lines and interactions of plant lines with insecticides.

Adult tomato psyllid, Bactericerca (Paratrioza) cockerelli (Sulc) (Homoptera: Psyllidae), behavioral responses were evaluated for five tomato plant lines and for the interactions of insecticides with four commercial cultivars. Plant lines tested included the commercial 'Shady Lady', 'Yellow Pear', '7718 VFN', 'QualiT 21', and the plant introduction line PI 134417. Insecticides included a kaolin particle film, pymetrozine, pyriproxyfen, spinosad, and imidacloprid. Psyllids spent significantly more time feeding on 'Yellow Pear' than all other plant lines except '7718 VFN'. In comparisons among plant lines, psyllids exposed to the wild accession PI 1.34417 showed a 98% reduction in feeding, a significant increase in jumping behavior, and a significant tendency to abandon the leaves, thereby demonstrating repellency, not just an antixenosis response. Interactions between plant lines and insecticides influenced behavioral responses. All insecticides tested significantly reduced feeding durations on all cultivars except the preferred 'Yellow Pear'. However, nonfeeding activities such as walking, probing, resting, and jumping varied substantially with chemical and cultivar combination. The behavior assay results offered insight into host resistance mechanisms, provided a useful technique for measuring effects of interaction of plant lines with insecticides, and generated information for selecting insecticides for specific cultivars used in integrated pest management program for the tomato psyllid.

Tomato Psyllid Behavioral Responses to Tomato Plant Lines and Interactions of Plant Lines with Insecticides

Adult tomato psyllid, Bactericerca (Paratrioza) cockerelli (Sulc) (Homoptera: Psyllidae), behavioral responses were evaluated for five tomato plant lines and for the interactions of insecticides with four commercial cultivars. Plant lines tested included the commercial 'Shady Lady', 'Yellow Pear', '7718 VFN', 'QualiT 21', and the plant introduction line PI 134417. Insecticides included a kaolin particle film, pymetrozine, pyriproxyfen, spinosad, and imidacloprid. Psyllids spent significantly more time feeding on 'Yellow Pear' than all other plant lines except '7718 VFN'. In comparisons among plant lines, psyllids exposed to the wild accession PI 1.34417 showed a 98% reduction in feeding, a significant increase in jumping behavior, and a significant tendency to abandon the leaves, thereby demonstrating repellency, not just an antixenosis response. Interactions between plant lines and insecticides influenced behavioral responses. All insecticides tested significantly reduced feeding durations on all cultivars except the preferred 'Yellow Pear'. However, nonfeeding activities such as walking, probing, resting, and jumping varied substantially with chemical and cultivar combination. The behavior assay results offered insight into host resistance mechanisms, provided a useful technique for measuring effects of interaction of plant lines with insecticides, and generated information for selecting insecticides for specific cultivars used in integrated pest management program for the tomato psyllid.

Adaptive changes in the appetite, growth and feeding behaviour of pony mares offered ad libitum access to a complete diet in either a pelleted or chaff-based form

AbstractSeven, 3-year-old pony mares (~230 kg) were used in a cross-over study to compare the appetite, energy and nutrient digestibilities, growth rate and feeding behaviour, when a complete diet was offered ad libitum in either the original loose-chaff mix (C), or as a more convenient, milled and pelleted preparation (P). Ad libitum access to the study diet (gross energy = 17·2 MJ/kg dry matter (DM)) was attained over 2 weeks. In the following 4 weeks, groups 1 (no. = 3) and 2 (no. = 4) received pelleted and chaff-based diets respectively. Dietary forms were exchanged during week 5 and ad libitum provision continued for a further 4 weeks. Behaviour and apparent nutrient digestibilities were assessed in weeks 3 and 4 of each period. Pelleted food had a lower proportion of water (P, 0·12; C, 0·22), but relative proportions of oil (0·04), crude protein (0·08), crude fibre (0·29), neutral-detergent fibre (NDF; 0·53) and gross energy (GE) were neither altered by food processing nor time. Apparent digestibilities (DM, 0·49; GE, 0·50; NDF, 0·40 in period 1) of the pelleted and chaff-based diets were similar within periods but decreased (P 0·01) to a similar extent for both diet types (proportional changes: DM, –0·14; GE, –0·16; NDF, –0·28) in period 2. Overall, mean intakes of digestible energy (DE) for chaff-fed animals during period 1 were 0·73 (P 0·001) of pellet DE intake (DEI). Mean DEI of pellets increased (P 0·001) during period 1 to attain 1·76 (s.e. 0·25) MJ/kg M0·75 on day 25. Following transfer from pellets to chaff, DEI decreased (P 0·001) to 0·68 (s.e. 0·07) MJ/kg M0·75 by the end of period 2. In contrast, DEI of animals which progressed from chaff to pellets remained relatively constant between periods. Oestrous behaviour caused no detectable change in the appetite of individual mares. Irrespective of differences in DEI, average daily gain (ADG) in body weight and condition score (CS) did not differ between groups. Overall, mean ADG decreased (P 0·01) from 1·54 (s.e. 0·17) kg/day in period 1 to 0·26 (s.e.0·08) kg/day in period 2. Changes in body weight were associated with CS (R2 = 0·72). Each CS point represented a 53·4 (s.e. 4·8) kg gain in body weight. Chaff meals were longer (30·6 (s.e. 1·6) min, P 0·001), less frequent (23·8 (s.e. 1·4) per day, P 0·001) and associated with a lower bite rate (3·8 (s.e.0·2) per min, P 0·001) and increased chewing requirement (23 (s.e. 1·2) per bite, P 0·001), which decreased the rate of DM intake (17·0 (s.e. 0·9) g/min, P 0·0.01). Overall, chaff-fed animals spent more time feeding (0·50 (s.e. 1·3) of the time; P 0·0.01), primarily at the expense of non-feeding activity and rest. The ad libitum feeding regime enabled stabled ponies to re-establish natural feeding patterns and offers a viable alternative to meal and forage feeding. The more slowly ingested chaff form maximized time spent feeding and limited changes in DEI during the introductory period. Although CS and ADG increased over the first 4 weeks, growth and appetite returned to near maintenance values within 9 weeks in association with a decrease in dietary energy intake and nutrient digestibility.

Validation of a radio frequency identification system for monitoring the feeding patterns of feedlot cattle

The feed bunk attendance patterns of six crossbred beef heifers (averaging 481±22 kg) and six crossbred beef steers (averaging 471±44 kg) being fed an 80% steam-rolled barley grain:15% barley silage and 5% supplement diet were monitored for 52 days using a radio frequency (RF) system (GrowSafe ® Systems Ltd., Airdrie, AB). The system was validated by three methods: (1) comparing the duration and frequency of feeding visits recorded by the RF system against those calculated from video surveillance data; (2) comparing the bunk attendance data provided by two separate RF transponders carried by a single animal; and (3) documenting the relationship between bunk attendance and actual feeding time. When one considered the ability of the RF system to monitor the presence or absence of an animal, total daily error in the RF system was 6% as compared to the videotaped data. Incidence of errors due to RF interference and false antennae readings were 2.4 and 3.6%, respectively. The RF system was concluded to be a highly effective tool for documenting bunk attendance. Feeding durations documented by animals bearing two transponders were highly correlated, averaging 88.4±1.5 and 84.5±1.5 min day −1 ( R 2=0.96). Frequency of bunk visits was also highly correlated ( R 2=0.96). Approximately 84% of total bunk attendance time was spent consuming feed; 16% was spent on non-feeding activity. On average, the cattle made 29±11.8 visits day −1, with 55.8% of visits associated with feeding activity and 44.2% with non-feeding activity. These observations suggest that attendance duration may be a better indicator of an animal’s feed intake than frequency of attendance at the bunk. Future studies with GrowSafe ® or other RF systems that do not automatically record feed intake should incorporate a correction factor to relate attendance to feeding time. Factors were identified that could introduce errors with the GrowSafe ® system. These include non-grounded, metal material (connected in a loop configuration), particularly when associated with the feed bunk area.

Eating behavior of lactating sows receiving growth hormone-releasing factor: effect of meal frequency and high-fiber gestation diets

Forty-eight Yorkshire × Landrace gilts were used in an experiment with a factorial design (2 × 2 × 2). The treatments were control or bulky diet during gestation (4.1 vs. 15.3% crude fiber), the number of meals served daily in lactation (2 or 4) and three daily s.c. injections of saline or of 1 mg of a human growth hormone-releasing factor analog (GRF) from day 3 to day 29 of lactation. The animals were video-recorded for 30 s every 5 min over a 24-h period and observed continuously at feeding time at weeks 2 and 4 of lactation. Injections of GRF to lactating sows decreased the time spent eating after feed distribution (P = 0.007) but not eating frequency over 24 h. GRF-treated sows performed more oral non-feeding activities after feed distribution and over 24 h (P &lt; 0.05). Sows fed four times a day spent less time eating and more time lying per feeding period than sows fed twice (P &lt; 0.05) but the total eating time over the day was similar. Lying frequency did not decrease in GRF-treated sows fed at 23:15 h, contrary to saline-injected sows (P = 0.02). Feeding high-fiber diets during gestation had no effect on eating behavior during lactation. In conclusion, GRF injections during lactation modified the eating behavior of sows. However, using a bulky diet during gestation or increasing meal frequency during lactation did not counteract the decrease in eating time due to GRF. Key words: Meal frequency, fiber, growth hormone-releasing factor, eating behavior, sows

The 5-HT 1B receptor agonist CP-94,253 reduces food intake and preserves the behavioural satiety sequence

The 5-HT IB receptor has been proposed as a link in the relationship between serotonin and satiety. However, the anorexia induced by RU-24969, a 5- HT 1 A 1 B agonist, has been shown to delay behaviours associated with the onset of satiety, increase the frequency of intake and increase some nonfeeding activities. CP-94,253 is a highly selective agonist at the 5-HT 1B receptor site with less affinity for other receptor sites, and has been used in this study to determine if agonism of 5-HT 1B receptor sites adjust the behavioural satiety sequence in a way consistent with satiety. The effects of an ED 50 of dose of CP-94,253 (5.0 mg/kg, IP) on eating behaviour of the fasted rat were monitored. Temporal profiles of behaviour duration and frequency were generated. Food intake was reduced 57% by CP-94,253 ( p < 0.005). Analysis confirmed that CP-94,253 reduced rearing ( p < 0.05) and increased resting ( p < 0.05) but preserved the overall pattern of the satiety sequence. Increased locomotion was not significant and caused no gross disruption of the behavioural repertoire. Such changes are also produced by prefeeding. In a second experiment, RU-24969 (1.0 mg/kg, IP) reduced food intake by only 30% ( p < 0.05) However, RU-24969 markedly disrupted the satiety sequence profile, which did not resemble the profile produced by prefeeding. RU-24969 presumably induces this disruption via a mechanism other than 5-HT 1B activation. The use of CP-95,253 demonstrates that selective activation of 5-HT IB receptor sites is sufficient to reduce food intake and enhance satiety as represented by the behavioural satiety sequence.