Effects of auditory, visual and chemical stimuli on the ingestive behavior of newly weaned piglets

Effects of milk replacer acidification and free-access feeding on early life feeding, oral, and lying behavior of dairy calves

Acidification is a practical way of preserving the bacteriological quality of milk so that it can be fed to calves under free-access conditions. The objectives of this study were to evaluate how milk replacer acidification and free-access feeding affect dairy calf behavior during the first week of life. Sixteen Holstein male calves were purchased at birth and transported to the University of Guelph Kemptville Campus Dairy Education and Research Centre. Calves were randomly assigned to 1 of 4 milk feeding programs: (1) free-access (ad libitum) feeding of acidified milk replacer (22% crude protein and 17% fat, 150 g/L; FA); (2) restricted (6 L/d, 150 g/L) feeding of acidified milk replacer (RA); (3) free-access feeding of nonacidified milk replacer (FN); and (4) restricted feeding of nonacidified milk replacer (RN). Formic acid was used to acidify milk replacer to a target pH between 4.0 and 4.5. Video recordings of each calf at 1, 2, and 6 d were analyzed continuously over 24 h for all occurrences of each behavior in the ethogram. Feeding behavior observations were organized into sucking bouts, from which feeding behavior outcome variables were calculated. Calves consuming acidified milk replacer demonstrated more fragmented feeding patterns, characterized by more pauses within a sucking bout (FA, FN, RA, and RN calves = 12.4, 4.4, 13.7, and 11.9 pauses/bout, respectively) and longer sucking bout duration (FA, FN, RA, and RN calves = 8.8, 5.2, 9.3, and 8.1 min/bout, respectively), than calves fed nonacidified milk replacer. Restricted-fed calves tended to have longer sucking bouts and performed more within-bout sucks (FA, FN, RA, and RN calves = 10.7, 5.8, 13.5, and 14.1, respectively) and pauses than free-access calves. Acidification and free-access feeding did not affect lying duration. Calves assigned to the acidified feeding treatments tended to perform more grooming behavior than those fed nonacidified milk replacer (FA, FN, RA, and RN calves = 0.9, 0.5, 0.8, and 0.6 h/d, respectively). Free-access feeding did not affect grooming duration. The observed differences in feeding and grooming behavior suggest that acidification to a pH between 4.0 and 4.5 may have altered the palatability of milk replacer. Calves assigned to the acidified milk replacer feeding treatments did not, however, show avoidance toward this feedstuff during the first week of life.

Review: Quantifying animal feeding behaviour with a focus on pigs

The study of animal feeding behaviour is of interest to understand feeding, to investigate the effect of treatments and conditions or to predict illness. This paper reviews the different steps to undertake when studying animal feeding behaviour, with illustrations for group-housed pigs. First, one must be aware of the mechanisms that control feeding and the various influences that can change feeding behaviour. Satiety is shown to largely influence free feeding (ad libitum and without an operant condition) in animals, but 'free' feeding seems a very fragile process, given the many factors that can influence feeding behaviour. Second, a measurement method must be chosen that is compatible with the goal of the research. Several measurement methods exist, which lead to different experimental set-ups and measurement data. Sensors are available for lab conditions, for research on group-housed pigs and also for on-farm use. Most of these methods result in a record of feeding visits. However, these feeding visits are often found to be clustered into meals. Thus, the third step is to choose which unit of feeding behaviour to use for analysis. Depending on the situation, either meals, feeding visits, other raw data, or a combination thereof can be suitable. Meals are more appropriate for analysing short-term feeding behaviour, but this may not be true for disease detection. Further research is therefore needed. To cluster visits into meals, an appropriate analysis method has to be selected. The last part of this paper provides a review and discussion of the existing methods for meal determination. A variety of methods exist, with the most recent methods based on the influence of satiety on feeding. More thorough validation of the recent methods, including validation from a behavioural point of view and uniformity in the applied methods is therefore necessary.

Modelling feeding behaviour, rate of feed passage and daily feeding cycles, as possible causes of fatigued pigs

This study was initiated to understand whether feeding behaviour and physiology may contribute to the rate of fatigued pigs at processing plants. Specifically, this study sought to determine: (1) how often pigs eat during the day, (2) the times of the day they eat and (3) a first approximation of the time from feed consumption to excretion (rate of passage) when housed in a group in conventional finishing facilities. Finally, models were constructed to try to predict the percentage of pigs with empty/diminished gastrointestinal (GI) tracts depending on the time of day of truck loading and transport durations. Pigs were randomly selected, weighed and selected for behavioural observations. From video records and live observations, the number of meals (feeding bouts) per day and the time of the day meals took place were recorded. Feed containing chromic oxide was fed to determine when a given meal was excreted. With the feeding times of day determined, models were constructed of the percentage of pigs that would have empty stomachs depending on the time of day pigs were removed from the barn and the length of transport/lairage. Finishing pigs housed in groups ate 5.6 ± 0.6 meals per day with an average feeding bout (meal) length of 11.3 ± 1.1 min. Many pigs fed ad libitum ate most of their meals during the afternoon and evening. The rate of passage of feed was 20.5 h (range = 18 to 24 h). Because fewer pigs ate in the late evening through morning, if pigs were shipped at these times they would have an increased risk of arriving at the stun at a plant with an empty GI tract. Some of the variation in rates of fatigued pigs and pork quality may be explained by times of day taken off feed and transport duration. Shipping in the afternoon or early evening may result in fewer pigs with empty/diminished GI tracts at processing which may influence the rate of fatigued pigs and pork quality.

Assessing pharmacokinetic variability directly induced by drug intake behaviour through development of a feeding behaviour-pharmacokinetic model

Variability in drug intake is increasingly recognized as a major source of variability in drug response. The non-uniform access to medicated feed, influenced by swine individual feeding behaviour, is a determinant of antibiotic exposure, recalling the intrinsic similarity with human compliance to drug regimens. In this paper, we developed a feeding behaviour-pharmacokinetic (FBPK) model of in-feed chlortetracycline (CTC) and established, in a definite way, the effect of feeding behaviour and its induced pharmacokinetic (PK) variability. Based on reported animal behaviour, we mathematically formulated swine feeding behaviour by incorporating its main characteristics: intense feeding periods that repeat on a daily basis and random feeding periods of free access to feed, along with growth stage factors. This behaviour model was then integrated into a PK model of CTC. Moreover, we analysed the effect of each feeding behaviour component and assessed the corresponding PK variability. We have been able to delineate the impact of different feeding behaviour components and characterize the induced PK variability. We have compared different therapeutic assumptions to our model and shown that random features underlying the feeding behaviour have dramatic influence on the PK variability. A practical tool to adopt the dosing regimen in terms of dose and age has been proposed. The method developed here can be generalized to other therapeutic contexts and incorporated into medical practice, particularly to make long-term projections of drug-intake behaviour, to explain possible treatment failure and guide practitioners in adjusting the dosing regimen.

Effect of drinker type and sound stimuli on early-weaned pig performance and behavior

Early-weaned pigs appear to be highly motivated to engage in motor patterns associated with nursing, which is thought to lead to the development of abnormal ingestive behaviors. If performance of these behaviors is related to sucking motivation, then the normal stimuli associated with nursing should stimulate pigs to perform these abnormal behaviors, specifically belly nosing. The goal of this study was to determine whether belly nosing could be affected by sow nursing vocalizations and whether the style of the drinker device influenced early-weaned pig behavior. Over six trials, 352 Yorkshire pigs were weaned at 15 d and assigned to pens (n = 44) of eight pigs based on litter, weight, and sex. Four pens in each of two rooms were outfitted with either a water nipple drinker or a drinker bowl. Rooms either had recorded sow vocalizations broadcast at hourly intervals or no sound (control). Pig behaviors were videotaped in a sample of pens (n = 32) on d 0, 1, 2, 5, 9, 11, 13, 16, and 18 after weaning. On d 0 to 2, pigs were observed continuously for feeding and drinking behaviors. On d 5 to 18, pigs were observed by scan sampling every 5 min for time budgets. Pigs with drinker bowls had higher apparent feed intakes during the first 2 d after weaning (P = 0.024), whereas they spent less time engaged in drinking behavior (P = 0.001). This coincided with an overall lower water use (P = 0.001) than that of pigs with nipple drinkers. Pigs with bowl drinkers also spent less time belly nosing than those with access to a nipple drinker (P = 0.012). Pigs in the sow vocalization treatment tended to have a higher ADG (P = 0.075), whereas they spent less time performing feeding behavior (P = 0.064). However, there was no effect of sow nursing grunts on belly nosing. These results suggest that there is a complex relationship between feeding, drinking and sucking, and belly nosing is not controlled by the same external stimuli as sucking. Because drinker type and the motor patterns that it accommodates affect belly nosing, it may be that the internal stimuli associated with nursing, such as the actual act of sucking, play a large role in the development of abnormal oral-nasal behaviors.