Variation In Feeding Behaviour Research Articles

PSXV-23 Effects of a nutritional packet composed of live yeast, vitamins, and electrolytes on the feeding behavior of intensively managed beef steers

Abstract The effect of a nutritional-packet was evaluated on time spent ruminating, eating, and chewing (ruminating + eating) by intensively managed beef steers consuming a finishing diet during the final 65 d of feeding prior to slaughter. Furthermore, the influence of behavior on CH4 production was determined. Twenty-four Angus-crossbreed steers were distributed into pens with SmartFeed (C-Lock) technology in which they were treated with: control or nutritional-packet [0.29% DM basis; live yeast (8.7 Log CFU/g); Vitamin C (5.4 g/kg); Vitamin B1 (13.33 g/kg); NaCl (80 g/kg); KCl (80 g/kg)]. An ear tag containing multiple accelerometers (CowManager) was placed on steers, and such device continuously recorded rumination and eating time (min/day). Enteric CH4 emissions were measured for 15 d using the SF6 tracer technique. Feeding behavior data were analyzed as a randomized complete block design using the MIXED procedure of SAS. The model included the fixed effect of treatment and the random effect of block. Steer was considered experimental unit. The GLM procedure of SAS was used for regressing behavior and CH4 production data. There were no differences between treatments for time (within 24 h) spent ruminating, eating, or chewing (P ³ 0.197). When nutrient intake was taken into account, no differences (P ³ 0.139) were observed between treatments for time spent ruminating, eating, and chewing per kg of dry matter, organic matter, neutral detergent fiber intake, and acid detergent fiber intakes. The production of CH4 was not affected by time spent ruminating (0.93 g/min; R2 = 0.0003; P = 0.935), eating (3.34 g/min; R2 = 0.03; P = 0.409), or chewing (0.69 g/min; R2 = 0.006; P = 0.728). The feeding behavior of intensively managed beef steers during the final 65-d of feeding was not driven by the nutritional-packet supplied, neither was CH4 production associated with feeding behavior variables measured.

Investigating the Effects of Distillers Grains on Heifer Feeding Behavior in the Finishing Phase.

Simple SummaryDried distillers grains (DDG), a corn by-product of the ethanol industry, are a common feedstuff in cattle diets. Distillers can be used in diets as an effective source of protein and can reduce risk of acidosis by reducing the highly fermentable carbohydrate of starch. However, the price and availability of distillers grains are variable based on droughts, energy prices, and other factors. When inclusion of distillers grains in diets becomes uneconomical or is not possible, diets may decrease in crude protein and increase in starch-altering rumen fermentation parameters and feeding behavior. The effect of distillers grains on cattle growth performance and carcass traits has been studied extensively, but little is known about how distillers inclusion affects feeding behavior. Therefore, the objective of this experiment was to determine the effect of low inclusion levels of DDG on feeding behavior in heifers consuming a high-moisture corn-based diet in the finishing phase. This study demonstrated that low inclusion levels of distillers grains has little effect on growth performance, but can alter feeding behavior and reduce variability in feeding behavior traits.The objective was to determine the effect of low inclusion levels of dried distillers grains (DDG) on feeding behavior in heifers consuming a high-moisture corn-based diet in the finishing phase. Simmental × Angus heifers (N = 90; 323 ± 50 kg) were fed for 180 d. Heifers were blocked by initial body weight (BW) into two groups, stratified by sire, and assigned to 15 pens with six heifers each. Pens were randomly assigned to one of three dietary treatments: 0% DDG inclusion (0DG), 7% DDG inclusion (7DG), or 14% DDG inclusion (14DG). Treatments did not affect (p > 0.59) BW, average daily gain, and gain:feed. Although there was a treatment × time effect (p = 0.05) for dry matter intake (DMI), with 0DG having greater DMI during the last 70 d, no differences in overall DMI were detected. Treatment affected (p < 0.01) bunk visit duration and head down duration, with 7DG and 14DG having less minutes per day. Bunk visit frequency (p = 0.02) was less variable for heifers fed 14DG and DMI tended (p = 0.08) to be less variable for both distillers treatments. While dietary inclusion of DDG has minimal effects on overall heifer performance, low levels of DDG inclusion can affect feeding behavior and intake variation.

Predicting feed intake using modelling based on feeding behaviour in finishing beef steers

Current techniques for measuring feed intake in housed cattle are both expensive and time-consuming making them unsuitable for use on commercial farms. Estimates of individual animal intake are required for assessing production efficiency. The aim of this study was to predict individual animal intake using parameters that can be easily obtained on commercial farms including feeding behaviour, liveweight and age. In total, 80 steers were used, and each steer was allocated to one of two diets (40 per diet) which consisted of (g/kg; DM) forage to concentrate ratios of either 494:506 (MIXED) or 80:920 (CONC). Individual daily fresh weight intakes (FWI; kg/day) were recorded for each animal using 32 electronic feeders over a 56-day period, and individual DM intakes (DMI; kg/day) subsequently calculated. Individual feeding behaviour variables were calculated for each day of the measurement period from the electronic feeders and included: total number of visits to the feeder, total time spent at the feeder (TOTFEEDTIME), total time where feed was consumed (TIMEWITHFEED) and average length of time during each visit to the feeder. These feeding behaviour variables were chosen due to ease of obtaining from accelerometers. Four modelling techniques to predict individual animal intake were examined, based on (i) individual animal TOTFEEDTIME relative expressed as a proportion of the dietary group (GRP) and total GRP intake, (ii) multiple linear regression (REG) (iii) random forests (RF) and (iv) support vector regressor (SVR). Each model was used to predict CONC and MIXED diets separately, giving eight prediction models, (i) GRP_CONC, (ii) GRP_MIXED, (iii) REG_CONC, (iv) REG_MIXED, (v) RF_CONC, (vi) RF_MIXED, (vii) SVR_CONC and (viii) SVR_MIXED. Each model was tested on FWI and DMI. Model performance was assessed using repeated measures correlations (R2_RM) to capture the repeated nature of daily intakes compared with standard R2, RMSE and mean absolute error (MAE). REG, RF and SVR models predicted FWI with R2_RM = 0.1–0.36, RMSE = 1.51–2.96 kg and MAE = 1.19–2.49 kg, and DMI with R2_RM = 0.13–0.19, RMSE = 1.15–1.61 kg and MAE = 0.9–1.28 kg. The GRP models predicted FWI with R2_RM = 0.42–0.49, RMSE = 2.76–3.88 kg and MAE = 2.46–3.47 kg, and DMI with R2_RM = 0.32–0.44, RMSE = 0.32–0.44 kg, MAE = 1.55–2.22 kg. Whilst more simplistic GRP models showed higher R2_RM than regression and machine learning techniques, these models had larger errors, likely due to individual feeding patterns not being captured. Although regression and machine learning techniques produced lower errors associated with individual intakes, overall precision of prediction was too low for practical use.

A novel feeding behavior index integrating several components of the feeding behavior of finishing pigs

Describing the feeding behavior of pigs is difficult given the large day-to-day variations observed for a given animal. The objectives of this study were to create an index that integrates the information from several components of feeding behavior in order to account for intra-animal variation within a day and between days, and to evaluate the capability of this index to study the impact of relevant nutritional factors affecting feeding behavior. Feed intake information from 160 pigs during the last 28 d of the growing phase from three studies was used. For each pig, the sum of the absolute values of the deviation areas between the regression line of the relative cumulative feed intake and the observed cumulative feed intake was used to calculate the weekly index measuring the irregularity of feed intake (IIFI). Spearman’s correlations of IIFI with the number of daily meals (r = −0.42; P < 0.001), meal duration (r = 0.38; P < 0.01), and feed intake per meal (r = 0.41; P < 0.01) indicate that pigs with high IIFI have fewer meals of longer duration and higher feed intake compared to pigs with low IIFI. This shows that IIFI captures information from several components of feeding behavior. Analysis of variance showed no effect of treatment on feeding behavior for datasets 1 and 2. However, the correlation between IIFI and dietary levels of CP (r = 0.34) indicates that diets high in CP were associated with pigs having more irregular meals. In dataset 3, pig feeding behavior was more regular in control diets than in pigs fed fibrous diets (IIFI; 164 vs. 197, respectively; P < 0.05). Additionally, IIFI was smaller in pigs fed canola by-product diets than in pigs fed wheat by-product diets, indicating that the source of fiber may also influence the feeding behavior of pigs. In most cases, IIFI was more effective at identifying differences in feeding behavior between dietary treatments than conventional feeding behavior variables. These results show the ability of IIFI to integrate information from several conventional components of the feeding behavior of pigs and its potential to successfully evaluate the effect of nutritional factors on feeding behavior.

Predicting body weight in growing pigs from feeding behavior data using machine learning algorithms

A timely and accurate estimation of body weight in finishing pigs is critical in determining profits by allowing pork producers to make informed marketing decisions on group-housed pigs while reducing labor and feed costs. This study investigated the usefulness of feeding behavior data in predicting the body weight of pigs at the finishing stage. We obtained data on 655 pigs of three breeds (Duroc, Landrace, and Large White) from 75 to 166 days of age. Feeding behavior, feed intake, and body weight information were recorded when a pig visited the Feed Intake Recording Equipment in each pen. Data collected from 75 to 158 days of age were split into six slices of 14 days each and used to calibrate predictive models. LASSO regression and two machine learning algorithms (Random Forest and Long Short-term Memory network) were selected to forecast the body weight of pigs aged from 159 to 166 days using four scenarios: individual-informed predictive scenario, individual- and group-informed predictive scenario, breed-specific individual- and group-informed predictive scenario, and group-informed predictive scenario. We developed four models for each scenario: Model_Age included only age, Model_FB included only feeding behavior variables, Model_Age_FB and Model_Age_FB_FI added feeding behavior and feed intake measures on the basis of Model_Age as predictors. Pearson’s correlation, root mean squared error, and binary diagnostic tests were used to assess predictive performance. The greatest correlation was 0.87, and the highest accuracy was 0.89 for the individual-informed prediction, while they were 0.84 and 0.85 for the individual- and group-informed predictions, respectively. The least root mean squared error of both scenarios was about 10 kg. The best prediction performed by Model_FB had a correlation of 0.83, an accuracy of 0.74, and a root mean squared error of 14.3 kg in the individual-informed prediction. The effect of the addition of feeding behavior and feed intake data varied across algorithms and scenarios from a small to moderate improvement in predictive performance. We also found differences in predictive performance associated with the time slices or pigs used in the training set, the algorithm employed, and the breed group considered. Overall, this study’s findings connect the dynamics of feeding behavior to body growth and provide a promising picture of the involvement of feeding behavior data in predicting the body weight of group-housed pigs.

Feeding Behavior of Lactating Dairy Cattle Fed Sorghum-Based Diets and Increasing Levels of Tannic Acid

Tannins have been used to trigger positive effects on ruminal metabolism and increase ruminant production efficiency, since they increase the supply of dietary protein in the small intestine. Increasing levels of tannic acid in a sorghum-based diet on the feeding behavior of five Holstein/Zebu crossbred lactating dairy cows was evaluated. They were subjected to a 5 × 5 Latin square experimental design, with fivelevels of tannin as dry matter (DM) in the diet (0.46, 1.30, 2.60, 3.90, and 5.20%). The levels of the tannic acid added were established based on the quantity of condensed tannin in high-tannin sorghum. Thus, diets 2, 3, 4 and 5 were supplemented with 1.5 g (13% DM), 79.5 g (2.6% DM), 157.5 g (3.9% DM), and 235.5 g (5.2% DM) of tannic acid, totaling 0.078, 0.156, 0.234, and 0.321 kg of tannin/day, respectively. Feeding behavior variables included the following states and events: feeding, drinking, rumination, and inactivity; the frequency of visiting the feed and water troughs; and the occurrence of urination and defecation. Water was provided ad libitum, and its intake was measured during periods of behavioral data collection. The use of two tannin sources (hydrolysable and condensed) corresponding to the total level of 5.20% (on a DM basis) in the diet of lactating dairy cattle does not affect the animals’ health. Tannic acid can be included in the diet of lactating dairy cattle at a level of 3.93% (on a DM basis) without inducing variation in the total time spent daily on feed intake. Dairy cows dilute the effects of dietary tannin (5.20%) through greater fragmentation of food consumption in the hours following its supply (180 min). The astringent effects caused by tannin intake in lactating dairy cows are mitigated by increasing the daily water intake as the amount of tannin in the diet increases, starting at a level of 3.90% tannin (on a DM basis).

Behavior of horses kept in different types of stalls in the semiarid region of Minas Gerais, Brazil

The objective of this study was to evaluate the feeding and agonistic behavior of Quarter Horses kept in different types of stalls in the semiarid region of Minas Gerais. A completely randomized design with two treatments (two types of stalls) and seven replicates (seven days of evaluation) was used. Four Quarter Horse mares and four stallions were used per treatment. Behavioral observations were made at 10-minute intervals for 24 hours. The stall environment was characterized by the following variables: air temperature, relative humidity, and black globe temperature for subsequent estimation of the wet-bulb globe temperature. Feeding behavior variables included: time spent eating concentrate and time spent eating roughage (hours), bite rate (bites/min), and the number of daily bites (bites/day). Zinc-roofed stalls had higher air temperatures than clay-roofed stalls and the external environment, averaging 28.2, 27.0, and 27.4 ºC, respectively, while relative humidity was significantly lower in the external environment (65.80%). Horses housed in zinc-roofed stalls had longer feeding times (8.32 h) than animals kept in clay-roofed stalls (7.22 h). Approximately 94% of the total feeding time was spent eating roughage and 73% of the time was spent resting and walking, regardless of the covering type. Although environmental variables showed thermal discomfort, the roofing material did not alter the feeding behavior of stabled horses in the semiarid region of Minas Gerais, suggesting an adaptation to the studied conditions. The feeding frequency should be increased to avoid a long resting time.

Feeding behaviour and activity as early indicators of disease in pre-weaned dairy calves

Across the industry, there is large variation in health status of dairy calves and as a result, disease incidence and antibiotic use is high. This has significant implications for animal welfare, productivity and profitability of dairy and dairy-beef production systems. Technology-based early detection systems could alleviate these issues; however, methods of early detection of disease in dairy calves have not been widely explored. This study aimed to determine whether changes in activity and feeding behaviour can be used as early warning indicators of respiratory disease in calves. In total, 100 pre-weaned male Holstein calves (age: ~8−42 days) were used. Calves were group-housed and provided with starter diet, straw bedding and ad libitum water. Calves were fed milk replacer ad libitum through an automatic calf feeder, and each calf was fitted with a leg-mounted activity monitor. Daily activity and feeding behaviour variables were calculated for each calf. Each calf was assessed daily using a modified version of the Wisconsin Scoring System to assess respiratory disease status. Calves were classed as ‘Diseased’, ‘Intermediate’ or ‘Healthy’ based on their cumulative health score. The peak day of the most extreme illness event was identified for each calf. Data from Diseased and Healthy calves were paired for analysis based on age and BW. Data were compared for the day of peak illness, and for the 3 days previous and post. Compared to healthy calves, diseased calves lay for longer and tended to have longer lying bouts (daily lying: 17.6 ± 0.3 vs 16.7 ± 0.2 h, P < 0.01; bout length: 74.8 ± 10.6 vs 56.0 ± 3.7 min, P = 0.09 for diseased and healthy calves, respectively). Diseased calves fed for a shorter time and had fewer feeder visits (with intake) each day compared to healthy calves (feeding time (min): 19.3 ± 1.4 vs 22.8 ± 1.5; P < 0.05; visits: 2.1 ± 0.2 vs 3.2 ± 0.4; P < 0.05). Importantly, differences between diseased and healthy calves were evident in both activity and feeding behaviour on the days prior to the peak day of disease. Lying bout length was greater in diseased calves for the 2 days prior to the peak day (P < 0.05), lying time was longer on day −1 (P < 0.05) and feeder visits with milk intake were less frequent on day −3 (P < 0.05). Thus, measurement of feeding and activity using precision technology within early detection systems could facilitate early intervention and optimized treatment.

229 The effects of direct-fed microbial with and without monensin plus tylan on performance, feed efficiency and feeding behavior patterns in feedlot steers

Abstract Objectives of this study were to evaluate the effects of DFM with and without Monensin plus Tylan on feed efficiency and feeding behavior patterns in steers. Crossbred steers (n = 125; BW = 303 kg) were randomly assigned to 1 of 4 treatments in a 2 x 2 factorial design: (1) control (no feed additives), (2) DFM only (25 g/d; Natur’s Way), (3) Monensin (40 g/ton) plus Tylan only (MON) and (4) DFM and MON. In pens with GrowSafe feedbunks, steers were fed the grower diet for 14 d and transitioned to a finisher diet on 16 d. During the grower/transition phase, MON-fed steers had 9.5% higher (P &amp;lt; 0.05) ADG and improved F:G (7.8 vs 8.94; P = 0.06) and RFI (-0.28 vs 0.27 kg/d; P &amp;lt; 0.01) vs CON-fed steers. DFM-fed steers had lower (P &amp;lt; 0.01) ADG, but similar F:G and RFI than CON-fed steers. Daily variances of bunk-visit event frequencies were reduced (P &amp;lt; 0.01) in MON- vs CON-fed steers. During the finisher period, MON x DFM interactions (P &amp;lt; 0.10) were observed for ADG and F:G. MON-fed steers had numerically improved F:G (5%) when DFM was excluded, but not when DFM was included. MON-fed steers had lower RFI (P &amp;lt; 0.01; -0.23 vs 0.23 kg/d), whereas DFM-fed steers had higher RFI (P &amp;lt; 0.01) compared to respective controls. MON-fed steers ate less (P &amp;lt; 0.01) DMI, spent 9% more (P &amp;lt; 0.05) time consuming meals and had 14% slower (P &amp;lt; 0.01) meal eating rate then CON-fed steers. The DFM did not positively affect feed efficiency. Although the magnitude of improvement in feed efficiency due to MON was small, results demonstrated that MON may minimize digestive upsets by reducing daily variation in feeding behavior during diet transition and slow meal-eating rate on high-grain diets.

Effect of thyme essential oil supplementation on feed intake, apparent digestibility, rumen fermentation, blood parameters and in vitro methane yield of Nellore cattle

The objective of this study was to evaluate the effects of thyme essential oil (TEO) supplementation, which has recognized antimicrobial and antioxidant activity, on feed intake, feeding behavior, ruminal fermentation and blood parameters of feedlot Nellore cattle, aiming to indicate the ideal TEO dose. Four ruminally-cannulated Nellore steers (500 ± 44 kg body weight) were randomly assigned in a 4 × 4 Latin square design and received one of the following experimental treatments: CON = control, with no TEO (423 g thymol/kg DM); T2 = 2 mL/d of TEO; T4 = 4 mL/d of TEO; and T8 = 8 mL/d of TEO. Each experimental period lasted 21 d (14 d for adaptation and 7 d for data collection). Dry matter (DM) intake and digestibility were not affected by TEO infusion (P≥0.11). Among feeding behavior variables, only “standing still” activity differed with TEO inclusion (Linear, P=0.03), with greater values observed when greater TEO doses were used. The in vitro total gas production was quadratically affected by TEO infusion (P=0.05). Ruminal pH tended to increase linearly from CON to T8 (P=0.09), while ammonia nitrogen concentrations tended to be quadratically affected (P=0.09). No TEO effect was observed for short-chain fatty acids (P≥0.11). TEO also did not affected blood parameters evaluated in this trial (erythrogram, leucogram, metabolites and liver enzymes [P≥0.11]). The TEO infusion of up to 8 mL/d did not promote deleterious effects on in vitro and in vivo nutritional and metabolic parameters of feedlot Nellore cattle. Further studies should be conducted to investigate the ideal TEO dose to improve beef cattle efficiency.

Inter- and intra-individual variability of feeding behaviour in group housed dairy goats

The emergence of precision livestock farming (PLF), and with it the increasing capacity to record behaviour and production parameters automatically, makes it possible to monitor feeding behaviour of individual animals over time. This study reports some of the first quantifications of feeding behaviour variables for individual dairy goats whilst group housed. The feeding behaviour of 16 non-lactating goats (NoLact), 32 goats in the middle of their first lactation (MidLact) and 24 goats (including 20 goats from MidLact) at the end of their first lactation (EndLact) from two breeds (Alpine and Saanen) was recorded. The goats were housed in groups of four individuals and each had access to one weight-monitored feeding station where they received a total mixed ration ad libitum twice a day. Following a habituation period, feeding behaviour was measured for nine days (NoLact), 10 days (MidLact) and six days (EndLact). After merging feeder visits into meals (≥8-min inter-meal-interval), six variables were calculated for each individual: meal frequency (number of daily meals, NDM), size (feed intake per meal, FIM) and duration (DUM), as well as feeding rate (FR), daily feeding time (DFT) and daily feed intake (DFI). The inter- and intra-individual variabilities of these six variables were investigated and the intra-class correlation coefficients calculated. Particular attention was paid to the first meal following feed distribution and to the stability of individual feeding behaviour between lactation stages. Effects of body weight, breed, and stage of lactation on the six feeding behaviour variables were analysed using a general linear model. Our study confirmed previous findings from individually housed dairy goats that feeding behaviour variables are relatively stable within an individual but show greater variability between individuals. Although there were differences between the lactation stages studied, the feeding behaviour of individuals tested in two lactation stages (mid- and end of lactation) remained relatively stable. The feeding behaviour variables were normally distributed, and smaller meals were linked with a higher meal frequency and vice versa. The first meal after a feed distribution, in addition to being positively correlated with the DFI, appeared to be stable in size for individual goats with a larger variability among individuals and could potentially be used to characterize the individuals, whereas time-related feeding behaviour variables appeared less useful for this purpose. Characterization of individuals based on their feeding behaviour can potentially be used to refine individual management for disease prevention or as a trait used in genetic selection.

Personality of dairy goats affects competitive feeding behaviour at different feeder heights

The feed bunk is a place of high competition for dairy goats, and high variability in feeding behaviour occurs; thus, it is necessary to understand why individuals respond differently when experiencing different feeding conditions. The objective of this study was to determine how personality traits affect competitive feeding behaviours of goats when feeding at a range of heights. Thirteen goats were provided one of three feeder heights (floor-, head-, and elevated-level) daily in a group pen under competitive feeding conditions and behaviours after feed delivery were recorded. Personality traits were assessed from behavioural responses toward two novelty and two fear tests; principal component analysis revealed four personality traits that were consistent over time: bold, fearful, exploratory and active-escape. These personality traits affected competitive behaviours, and often depended on feeder height. ‘Bold’ goats initiated more aggressive interactions, especially behind the floor-level feeder, and had greater feeding times; the opposite was observed in ‘fearful’ goats, which more often waited for access to the feeder. ‘Exploratory’ goats were less involved in aggressive interactions and spent less time feeding at the floor-level feeder, and more time feeding at the elevated-level feeder. While the findings are limited to a single group of goats, our pilot study suggests that personality traits may explain variability in feeding aggression and feeding time of goats under competitive feeding conditions, and that these differences may be promoted by feed offered at different heights. Further work is needed in larger groups of goats to understand why individuals appear to cope with competitive feeding practices in different ways.

Assessing feed attractability in Pacific white shrimp (Litopenaeus vannamei) using an automated tracking software

In shrimp farming, there has been a considerable focus on the development of novel additives that might reduce costs associated with the time taken by shrimp to locate and ingest feed. However, within these trials there has been little consideration of the role that feeding behaviour of individuals can play in assessing the attractability of additives. As such, the use of tracking technologies in the development of automated protocols is beginning to gain attention as an important tool for monitoring associated behaviours. Therefore the objective of the present study was to validate an automated tracking software (EthoVision) for assessing feed attractability in Pacific white shrimp (Litopenaeus vannamei). Twenty-seven juvenile shrimp (5.54 ± 1.37 g) were used to test three experimental diets with different theoretical levels of attraction; negative (0.07 M quinine-HCl), control, and positive diet (3% attractant). Shrimp were individually video recorded in test arenas for 20 min with each one of the diets. Recordings were also carried out at two times of day (morning and afternoon) to evaluate the effect of time of day on shrimp feeding behaviour. The behaviour of each individual was recorded three times per diet to determine levels of individual variation. Comparison between manual and automated observations validated the reliability of EthoVision in analysing L. vannamei feeding behaviour and the software detected clear differences in feeding behaviour according to diet. Shrimp provided with the positive diet (i.e. 3% attractant) arrived faster and spent longer on the feeding area. In contrast, with the negative diet (i.e. 0.07 M quinine-HCl), shrimp spent more time moving around the test arena and less time interacting with the feed. Time of day also had an effect on several behaviours, but not on the time spent on the feeding tray. Less individual variation in feeding behaviours was found when shrimp were fed the positive diet, suggesting attractive diets can decrease variability in feeding behaviour with potential applications to commercial ponds. Distribution heatmaps provided by EthoVision offered a quick and reliable assessment of feed attractability. The results of this study highlight the use of tracking technologies to assess feed attractability in L. vannamei and the feasibility of automated protocols for the industry.

Large variability in feeding behavior among crossbred growing cattle.

The purpose of this study was to define an extensive suite of feeding behavior traits in growing crossbred cattle and to investigate their phenotypic inter-relationships as well as relationships with other performance and efficiency traits. Time-series feeding behavior data, as well as feed intake and liveweight records, were available for 624 growing crossbred cattle, of which 445 were steers and 179 were heifers. Feeding behavior repeatability estimates were calculated using linear mixed models. Additionally, partial Spearman correlations were estimated among 14 feeding behavior traits, as well as between feeding behavior with both performance and feed efficiency traits, using residuals retained from linear mixed models. The marginal contribution of several feeding behavior traits to the variability in metabolizable energy intake (MEI) was also determined. Repeatability estimates of 0.57, 0.36, and 0.48 were calculated for the number of feed events per day, the total time spent feeding per day, and the feeding rate, respectively. Cattle that ate more frequently each day, ate at a faster rate and consumed less energy in each visit to the feed bunk. More efficient cattle fed less often per day and fed for a shorter duration per day; they also had a slower feeding rate and fed for longer in each visit to the feed bunk. Moreover, heavier cattle fed for a longer duration per day had a faster feeding rate, but fed less often per day; heavier animals also fed first in the pen after the fresh feed was offered. The number of feed events per day and feeding time per day together explained an additional 13.4 percentage points of the variability in MEI above that already explained by all of growth rate, liveweight, and backfat depth. The results from the present study suggest that several repeatable time-series-related feeding behavior traits, that are less resource intensive to measure, may have a role as useful predictor traits of important but relatively difficult to record traits, such as feed intake and efficiency.

Seasonal variation in feeding behaviour and foraging success of Indian pond heron (Ardeola grayii) in different habitats

Objectives: The present study was focused on feeding behaviour and foraging success of Indian pond heron (Ardeola grayii) in different seasons and habitats. Methods: The study was carried out in three habitats, lake, pond and marshy area from September 2016 to December 2017. All activities such as feeding behaviour, foraging success, prey abundance, success ratio, feeding frequency (foraging attempt and success) of A. grayii were compared in three habitats with three seasons by using binocular and video recorder. Statistical analysis: Data were analysed by SPSS (21 version) and graph pad prism. In this study, prey abundance and foraging success in three habitats and season differed statistically significant (p < 0.05). By using non-linear regression on foraging attempt and success in three habitats three curve (exponential, cubic, growth and power) best fitted to analyzed data sets. These curve shows variation in feeding pattern. Findings: Stand and wait is dominant feeding behaviour followed by walk slowly and walk quickly in all three habitats and season. Prey was abundantly present during monsoon, as a result feeding frequency and success ratio maximized. Structure of habitats, vegetation, and water depth also influenced foraging success of Ardeola grayii. Thus, overall finding showed that Indian pond heron feeding behaviour and foraging success affected by structure of habitats and seasons. Keywords: Habitat; season; feeding; frequency; behaviour; prey

Efficacy of statistical process control procedures to identify deviations in continuously measured physiologic and behavioral variables in beef steers experimentally challenged with Mannheimia haemolytica.

The objective of this experiment was to determine if statistical process control (SPC) procedures coupled with the remote continuous collection of feeding behavior patterns, accelerometer-based behaviors, and rumen temperature can accurately differentiate between animals experimentally inoculated with Mannheimia haemolytica (MH) or PBS. Thirty-six crossbred steers (BW = 352 ± 23 kg) seronegative for MH were randomly assigned to bronchoselective endoscopic inoculation with MH (n = 18) or PBS (n = 18). Electronic feed bunks were used to measure DMI and feeding behavior traits, accelerometer-based neck collars measured feeding- and activity-behavior traits, and ruminal thermo-boluses measured rumen temperature. Data were collected for 28 d prior to and following inoculation. Steers inoculated with MH exhibited elevated (P < 0.02) levels of neutrophils and rumen temperature indicating that MH challenge effectively stimulated immunologic responses. However, only nine of the MH steers exhibited increased serum haptoglobin concentrations indicative of an acute-phase protein response and one displayed clinical signs of disease. Shewhart charts (SPC procedure) were used for two analyses, and sensitivity was computed using all MH-challenged steers (n = 18), and a subset that included only MH-challenged haptoglobin-responsive steers (n = 9). Specificity was calculated using all PBS steers in both analyses. In the haptoglobin-responsive only analysis, DMI and bunk visit (BV) duration had the greatest accuracy (89%), with accuracies for head-down (HD) duration, BV frequency, time to bunk, and eating rate being less (83%, 69%, 53%, and 61%, respectively). To address the diurnal nature of rumen temperature, data were averaged over 6-h intervals, and quarterly temperature models were evaluated separately. Accuracy for the fourth quarter rumen temperature was higher (78%) than the other quarterly temperature periods (first = 56%, second = 50%, and third = 67%). In general, the accelerometer-based behavior traits were highly specific ranging from 82% for ingestion to 100% for rest, rumination, and standing. However, the sensitivity of these traits was low (0% to 50%), such that the accuracies were moderate compared with feeding behavior and rumen temperature response variables. These results indicate that Shewhart procedures can effectively identify deviations in feeding behavior and rumen temperature patterns to enable subclinical detection of BRD in beef cattle.

Repeatability of traits for characterizing feed intake patterns in dairy goats: a basis for phenotyping in the precision farming context

In ruminants, feeding behaviour variables are parameters involved in feed efficiency that show variation among individuals. This study aimed to evaluate during the first two production cycles in ruminants the repeatability of feed intake pattern, which is an important aspect of feeding behaviour. Thirty-five dairy goats from Alpine or Saanen breeds were housed in individual pens at four periods (end of first gestation, middle of first and second lactations and middle of second gestation which is also the end of first lactation) and fed a total mixed ration (TMR) ad libitum. Individual cumulative dry matter intake (DMI) was automatically measured every 2 min during the last 4 days of each period. Feed intake pattern was characterized by several measures related to the quantity of feed eaten or to the rate of intake during the 15 h following the afternoon feed delivery. Two main methods were used: modelling cumulative DMI evolution by an exponential model or by a segmentation-clustering method. The goat ability to sort against dietary fibre was also evaluated. There was a very good repeatability of the aggregate measures between days within a period for a given goat estimated by the day effect within breed and goat, tested on the residual variance (P > 0.95). The correlations between periods were the highest between the second and either the third or fourth periods. With increasing age, goats sorted more against the fibrous part of the TMR and increased their initial rate of intake. Alpine goats ate more slowly than Saanen goats but ate during a longer duration. Principal component analysis (PCA) was performed on all the aggregate measures of feed intake patterns. The factor score plots generated by the PCA highlighted the opposition between the different measures of feed intake patterns and the sorting behaviour. The projection of the animals on the scoring plots showed a breed effect and that there was a continuum for the feed intake pattern of goats. In conclusion, this study showed that the feed intake pattern was highly repeatable for an animal in a given period and between periods. This means that phenotyping goats in a younger age might be of interest, either to select them on feeding behaviour and choose preferentially the slow eaters or to adapt the quantity offered and restrict feed delivery to the fast eaters in order to increase feed efficiency and welfare by limiting the occurrence of acidosis, for example.

Feedlot performance and rumen morphometrics of Nellore cattle adapted to high-concentrate diets over periods of 6, 9, 14 and 21 days

The energy content of finishing diets offered to feedlot cattle may vary across countries. We assumed that the lower is the energy content of the finishing diet, the shorter can be the adaptation period to high-concentrate diets without negatively impacting rumen health while still improving feedlot performance. This study was designed to determine the effects of adaptation periods of 6, 9, 14 and 21 days on feedlot performance, feeding behaviour, blood gas profile, carcass characteristics and rumen morphometrics of Nellore cattle. The experiment was designed as a completely randomised block, replicated 6 times, in which 96 20-month-old yearling Nellore bulls (391.1 ± 30.9 kg) were fed in 24 pens (4 animals/pen) according to the adaptation period adopted: 6, 9, 14 or 21 days. The adaptation diets contained 70%, 75% and 80.5% concentrate, and the finishing diet contained 86% concentrate. After adaptation, one animal per pen was slaughtered (n = 24) for rumen morphometric evaluations and the remaining 72 animals were harvested after 88 days on feed. Orthogonal contrasts were used to assess linear, quadratic and cubic relationships between days of adaptation and the dependent variable. Overall, as days of adaptation increased, final BW (P = 0.06), average daily gain (ADG) (P = 0.07), hot carcass weight (P = 0.04) and gain to feed ratio (G : F) (P = 0.07) were affected quadratically, in which yearling bulls adapted by 14 days presented greater final BW, ADG, hot carcass weight and improved G : F. No significant (P > 0.10) days of adaptation effect was observed for any of feeding behaviour variables. As days of adaptation increased, the absorptive surface area of the rumen was affected cubically, where yearling bulls adapted by 14 days presented greater absorptive surface area (P = 0.03). Thus, Nellore yearling bulls should be adapted by 14 days because it led to improved feedlot performance and greater development of rumen epithelium without increasing rumenitis scores.

Widespread infection of Areospora rohanae in southern king crab (Lithodes santolla) populations across south Chilean Patagonia.

Cottage cheese disease is caused by microsporidian parasites that infect a wide range of animal populations. Despite its potential to affect economically important activities, the spatial patterns of prevalence of this disease are still not well understood. Here, we analyse the occurrence of the microsporidian Areospora rohanae in populations of the king crab Lithodes santolla over ca 800 km of the southeastern Pacific shore. In winter 2011, conical pots were deployed between 50 and 200 m depth to capture crabs of a wide range of sizes. The infection was widely distributed along the region, with a mean prevalence of 16%, and no significant association between prevalence and geographical location was detected. Males, females and ovigerous females showed similar prevalence values of 16.5 (13–18.9), 15 (9.2–15) and 16.7% (10–19%), respectively. These patterns of prevalence were consistent across crab body sizes, despite the ontogenetic and sex-dependent variations in feeding behaviour and bathymetric migrations previously reported for king crabs. This study provided the first report of the geographical distribution of A. rohanae infecting southern king crabs.

Feeding behaviour and pre-prandial status affect post-prandial plasma energy metabolites and insulin kinetics in growing pigs fed diets differing in fibre concentration.

Variations in feeding behaviour between animals result from individual variations in their metabolism as affected by diet composition. The study aimed to link the within-day dynamics of voluntary feed intake and those of blood metabolites and insulin in growing pigs having ad libitum access to feed and receiving diets differing in dietary fibre levels and aleurone supplementation. A total of forty pigs (body weight: 35 kg) had access to diets provided ad libitum, which differed by fibre content (13 or 18 % neutral-detergent fibre) and aleurone supplementation (0, 2 or 4 g/kg). Feeding behaviour was individually recorded for 1 week.The kinetic of plasma metabolites and insulin was followed for 1 h after a voluntary test meal. Dietary fibre level did not affect the daily feed intake but increased meal size and meal duration. Aleurone supplementation (4 g/kg) decreased the daily feed intake and number of meals. Dietary fibre level only decreased insulin concentration measured 15 min after meal beginning. Aleurone supplementation (4 g/kg) decreased glycaemia in the first hour after the meal and insulinaemia 15 min after the meal. Free access to feed led to high variability in pre-prandial metabolites and insulin concentrations, resulting in different test meal size irrespective of diet composition. Animals were then spread over different profiles combining feeding behaviour and fasted status to explain different profiles of regulation of feed intake. Plasma metabolites and insulin kinetics were affected by diet composition but also by animal characteristics. Individual variability should be considered when diet composition is used to modulate feeding behaviour.