Feed intake and feeding behavior traits for gestating sows recorded using electronic sow feeders

Electronic sow feeding (ESF) systems are used to control feed delivery to individual sows that are group-housed. Feeding levels for gestating sows are typically restricted to prevent excessive body weight gain. Any alteration of intake from the allocated feeding curve or unusual feeding behavior could indicate potential health issues. The objective of this study was to use data recorded by ESF to establish and characterize novel feed intake and feeding behavior traits and to estimate their heritabilities. Raw data were available from two farms with in-house manufactured (Farm A) or commercial (Farm B) ESF. The traits derived included feed intake, time spent eating, and rate of feed consumption, averaged across or within specific time periods of gestation. Additional phenotypes included average daily number of feeding events (AFE), along with the cumulative numbers of days where sows spent longer than 30 min in the ESF (ABOVE30), missed their daily intake (MISSF), or consumed below 1 kg of feed (BELOW1). The appetite of sows was represented by averages of score (APPETITE), a binary value for allocation eaten or not (DA_bin), or the standard deviation of the difference between feed intake and allocation (SDA-I). Gilts took longer to eat than sows (15.5 ± 0.13 vs. 14.1 ± 0.11 min/d) despite a lower feed allocation (2.13 ± 0.00 vs. 2.36 ± 0.01 kg/d). The lowest heritability estimates (below 0.10) occurred for feed intake traits, due to the restriction in feed allocation, although heritabilities were slightly higher for Farm B, with restriction in the eating time. The low heritability for AFE (0.05 ± 0.02) may have reflected the lack of recording of nonfeeding visits, but repeatability was moderate (0.26 ± 0.03, Farm A). Time-related traits were moderately to highly heritable and repeatable, demonstrating genetic variation between individuals in their feeding behaviors. Heritabilities for BELOW1 (Farm A: 0.16 ± 0.04 and Farm B: 0.15 ± 0.09) and SDA-I (Farm A: 0.17 ± 0.04 and Farm B: 0.10 ± 0.08) were similar across farms. In contrast, MISSF was moderately heritable in Farm A (0.19 ± 0.04) but lowly heritable in Farm B (0.05 ± 0.07). Heritabilities for DA_bin were dissimilar between farms (Farm A: 0.02 ± 0.02 and Farm B: 0.23 ± 0.10) despite similar incidence. Individual phenotypes constructed from ESF data could be useful for genetic evaluation purposes, but equivalent capabilities to generate phenotypes were not available for both ESF systems.     

Systematic analysis of feeding behaviors and their effects on feed efficiency in Pekin ducks

Background: Feeding behavior study is important for animal husbandry and production. However, few studies were conducted on the feeding behavior and their relationship with feeding efficiency in Pekin ducks. In order to investigate the feeding behavior and their relationship with feed efficiency and other economic traits in Pekin ducks, we selected 358 male Pekin ducks and recorded feeding information between 3 to 6 wk of age using automatic electronic feeders, and compared the feeding behavior under different residual feed intake(RFI) levels.Results: We observed that total feed time, daily feed intake and feed intake per meal had strong positive correlations with feed efficiency traits; moreover, strong correlation between feed intake per meal and body weight was found(R=0.32, 0.36). Daily feeding rate meal and meal duration had weak correlations with feed efficiency(R=0.14~0.15). The phenotypic correlation of between-meal pauses, with feed efficiency was not observed. When daily changes were analyzed, high RFI ducks had the highest feed consumption over all times, and obvious differences in daily visits were found among different RFI level animals during the middle period; these differences were magnified with age, but there was no difference in daily meal number. Moreover, our data indicate that high RFI birds mainly take their meals at the edge of the population enclosure, where they are more susceptible to environmental interference.Conclusions: Overal, this study suggests that the general feeding behaviors can be accurately measured using automatic electronic feeders and certain feeding behaviors in Pekin ducks are associated with improved feed efficiency.     

Detailed genetic analysis of feeding behaviour in Romane lambs and links with residual feed intake

Breeding strategies based on feed efficiency are now implemented in most animal species using residual feed intake (RFI) criteria. Although relevant, the correlated responses of feeding behaviour traits resulting from such selection on RFI are poorly documented. We report the estimated feeding behaviour at three time levels (visit, meal and day) and genetic parameters between the feeding behaviour traits and their links with RFI and its components. Feed intake, feeding duration at three time levels (per visit, meal and day), feeding rate, number of visits and time‐between‐visits were estimated for 951 Romane lambs fed via automatic concentrate feeders. Heritability estimates of feeding behaviour traits ranged from 0.19 to 0.54 with higher estimates for the day level than the visit level. Daily feed intake was not genetically linked to feed intake at the visit level, whereas feeding duration between visit and day levels was moderately correlated (R_g = +0.41 ± 0.12). RFI was not significantly correlated with feeding rate, but was positively linked to feed intake and feeding duration at the day level (+0.73 ± 0.09 and +0.41 ± 0.13, respectively) and negatively at the visit level (?0.33 ± 0.14 and ?0.22 ± 0.17, respectively). Selecting animals with lower RFI values might modify their feeding behaviour by increasing feed intake and feeding duration at the visit level but decrease the number of visits per day (+0.51 ± 0.14).     

Effects of protein source and lipid supplementation on conservation and feed value of total mixed ration silages for finishing beef cattle

The objective of this study was to examine the conservation process and feed value of total mixed ration (TMR) silages. In exp. 1, we evaluated the fermentation pattern and aerobic stability of TMR silages containing different protein and lipid supplementations. In exp. 2, we compared the performance of finishing beef heifers fed those TMR silages. In both experiments, treatments were as follows: ensiled TMR with urea (U); ensiled TMR without a protein supplement at ensiling, but soybean meal supplemented at feeding to balance diet crude protein (CP) in exp. 2 (SMnf; where the acronym nf indicates nonfermented); ensiled TMR with soybean meal (SM); and ensiled TMR with rolled soybean grain (SG). Thirty-two Nellore heifers (313 ± 8.8 kg shrunk body weight [SBW]) were blocked by initial SBW, housed in individual pens, and enrolled in exp. 2 for 82 d. In exp. 1, treatment without a protein supplement (SMnf) had a lower content of CP, soluble CP, NH₃-N, pH, and Clostridium count compared with U (P ≤ 0.03). Lactic acid concentrations tended to be reduced for SMnf compared with U (P = 0.09). Ethanol concentration was reduced in SG compared with SM (P < 0.01). 1,2-Propanediol concentration was increased in SMnf compared with U (P < 0.01), reduced in SM compared with SMnf (P = 0.02), and increased in SG compared with SM (P = 0.02). Dry matter (DM) loss during fermentation was low and similar among treatments (~3.7%). All silages remained stable during 10 d of aerobic exposure after feed out. Considering fermentation traits, such as pH (≤4.72), NH₃-N (<10% of N, except for U treatment), butyric acid (<0.05 % DM), and DM losses (<3.70% DM), all silages can be considered well conserved. In exp. 2, diets were isonitrogenous because soybean meal was added to SMnf before feeding. Compared with SM, cattle fed SG made more meals per day (P = 0.04) and tended to have a decreased intermeal interval (P = 0.09). DM intake, average daily gain, final SBW, hot carcass weight, Biceps femoris fat thickness, and serum levels of triglycerides and cholesterol were increased for SG compared with SM (P ≤ 0.05). In brief, TMR silages exhibited an adequate fermentation pattern and high aerobic stability. The supplementation of true protein did not improve animal performance, whereas the addition of soybean grain as a lipid source improved the performance of finishing cattle fed TMR silages.     

Estimation of heritability of feeding behaviour traits and their correlation with production traits in Finnish Yorkshire pigs

A major proportion of the costs of pork production is related to feed. The feed conversion rate (FCR) or residual feed intake (RFI) is thus commonly included in breeding programmes. Feeding behaviour traits do not directly have economic value but, if correlated with production traits, can be used as auxiliary traits. The aim of this study was to estimate the heritability of feeding behaviour traits and their genetic correlations with production traits in the Finnish Yorkshire pig population. The data were available from 3,235 pigs. Feeding behaviour was measured as the number of visits per day (NVD), time spent in feeding per day (TPD), daily feed intake (DFI), time spent feeding per visit (TPV), feed intake per visit (FPV) and feed intake rate (FR). The test station phase was divided into five periods. Estimates of heritabilities of feeding behaviour traits varied from 0.17 to 0.47. Strong genetic correlations were obtained between behaviour traits in all periods. However, only DFI was strongly correlated with the production traits. Interestingly, a moderate positive genetic correlation was obtained between FR and backfat thickness (0.1–0.5) and between FR and average daily gain (0.3–0.4), depending on the period. Based on the results, there is no additional benefit from including feeding‐related traits other than those commonly used (FCR and RFI) in the breeding programme. However, if correlated with animal welfare, the feeding behaviour traits could be valuable in the breeding programme.     

The relationship between meal composition and long-term diet choice

When animals are offered a choice of feeds that are nutritionally complementary, they are able to select a consistent combination of these feeds over long periods of time. Analysis of how such consistent diet choice is achieved, in terms of short-term feeding behavior, may further our knowledge of how animals regulate nutrient intake. Previous work, on meal pattern analysis and on nutrient synchronization, led us to hypothesize that animals may select a consistent diet within a meal. In three experiments cows were offered a choice between high- (H) and low- (L) protein feeds and short-term feeding behavior data were collected using computerized feeders. Feeding behavior was first analyzed in terms of visit characteristics. A greater average daily intake of H, relative to L, was more closely related to the ratio of H visits to L visits than to differences in the intake per visit to feeders supplying H or L. Individual meal criteria were estimated using a mixed-distribution model, and visits were clustered into meals. Cows typically had approximately six meals per day. The observed frequency distribution of meal composition, in terms of the proportion of visits to H feeders, was determined. Subsequently, the observed visits were randomly reclustered into bouts consisting of the same number of visits as were observed in meals, and the frequency distribution of random bout composition was calculated. If frequency distributions of meals and random bouts coincide, then this is evidence that cows do not regulate diet choice within a meal. Comparison of the frequency distributions of meals and random bouts provided no evidence that cows attempted to achieve their long-term average diet composition within a meal. We also investigated whether cows tried to achieve a consistent diet choice within a meal by adjusting their intake per visit, depending on the feed type visited and the proportion of visits to H feeders in a meal. There was no evidence that this occurred. In conclusion, our analyses have shown that cows did not attempt to select within a meal a consistent diet in terms of protein to energy ratio. Indeed, our data and the literature suggest that the timeframe over which the intake of energy and protein is regulated must be greater than a meal in a number of animal species.     

Effect of selection for residual feed intake on feeding behavior and daily feed intake patterns in Yorkshire swine

Residual feed intake (RFI) is a measure of feed efficiency defined as the difference between observed and predicted feed intake based on average requirements for growth and maintenance. The objective of this study was to evaluate the effect of selection for decreased RFI on feeding behavior traits and to estimate their relationships with RFI. Three data sets from the 4th and 5th generations of a selection experiment with a line selected for reduced RFI (LRFI) and a randomly selected control line (CTRL) were analyzed. Lines were mixed in pens of 16 and evaluated for feeding behavior traits obtained from a single-space electronic feeder over a growing period of ~3 mo before ~115 kg. The following traits were evaluated as averages over the entire test period and over the first and second half of the test period: number of visits per day and hour; occupation time per day, visit, and hour; feed intake (FI) per day, visit, and hour; and FI rate per visit. Models used included fixed effects of line and feeder, covariates of on-test age and FI per day, and random effects of pen, on-test group, sire, and litter. Repeated measures models were used to analyze feeding patterns during the day. The LRFI pigs had significantly less FI per day than CTRL pigs for all 3 data sets. With adjustment for FI per day, line differences of all traits were in the same direction for all 3 data sets but differed in significance and size. Feed intake per visit and hour and visits per day and hour did not differ between lines, but the trend was for LRFI pigs to have fewer visits, in particular during peak eating times. The LRFI pigs had a greater feeding rate and less occupation time per day, visit, and hour than CTRL pigs, but this was not significant for all data sets. Correlations of RFI with FI per day and visit and visits per day were positive. Average daily gain was positively correlated with FI per day and visit and occupation time per visit but negatively correlated with visits per day. Feed intake per day was positively correlated with backfat. In conclusion, feed efficiency may be affected by FI behavior because selection for decreased RFI has resulted in pigs that spend less time eating and eat faster.     

The effect of feeding time (day versus night) and feeding frequency on pancreatic exocrine secretion in pigs

The effect of night feeding and feeding frequency on exocrine pancreatic secretion was studied in five chronically catherized growing pigs (16 to 31 kg). Feeding during the night (2200 to 2400 h) as compared to the day (1000 to 1200 h) tended to stimulate cholesterol ester lipase activity and tended to lower the colipase : lipase ratio in the pancreatic juice, but no effect on volume output, protein output and the activities of trypsin, chymotrypsin, amylase, lipase and colipase could be demonstrated. Feeding 12 small meals between 0800 and 2000 h as compared to one large meal (1000 to 1200 h) daily, altered the pattern of exocrine pancreatic secretion, tended to stimulate protein output by 44 %, chymotrypsin activity by 29 % and lipase activity by 46 %. These observations strengthened the theory that exocrine pancreatic secretion is partly regulated by feed intake per se and does not only depend on the amount of feed consumed. Feeding 12 small meals versus one large meal, compared at the same total daily feed intake, lowered the colipase : lipase ratio by 32 %. It can be concluded that feed intake pattern affected exocrine pancreatic secretion.     

Increasing daily feeding occasions in restricted feeding strategies does not improve performance or well being of fattening pigs

Background

The natural feeding behaviour of the pig is searching for feed by rooting activities throughout the day; self-feeding pigs randomly space their eating and drinking periods throughout the day consuming ten to twelve meals per day. Pigs in conventional fattening pig production are normally fed 2–3 times daily with the feed consumed within 15 minutes. The aim of this study was to determine if more frequent feedings could improve the performance of conventionally kept fattening pigs.

Methods

The experiment was carried out on 360 fattening pigs (27–112 kg live weight), weighed and assigned to pens stratified by weight and sex. Each treatment group consisted of 180 pigs, allocated to 20 pens with nine pigs in each pen. To evaluate how more feeding occasions affects performance and well-being the pigs were divided into two groups and fed three (control group) or nine (treatment group) times daily. The same total amount of liquid feed was fed to each group and the feed ration was correlated to the live weight of the pigs. All weight and slaughter recordings were made individually and recordings of feed consumption were made pen-wise. At slaughter the stomach of each pig was examined for lesions in the pars oesophagea and scored on a scale from 1–6.

Results

Frequent feeding occasions influenced both performance and status of gastric lesions of the pigs adversely. Pigs in the treatment group grew slower compared to pigs in the control group; 697 g/day (± 6.76) versus 804 g/day (± 6.78) (P < 0.001) with no difference in within-pen variation. There was also a lower prevalence of gastric lesions within pigs in the control group (2.4 (± 0.12) compared to 3.0 (± 0.12) (P < 0.01)). There was a positive correlation between gastric lesions in the treatment group and daily weight gain (r = 0.19; P < 0.01).

Conclusion

Increased daily feeding occasions among group housed pigs resulted in a poorer daily weight gain and increased mean gastric lesion score as compared with pigs fed three times daily. This may be a consequence of more frequently occurring competition for feed in the treatment group. The present study does not support increased daily feeding occasions in fattening pigs.     

A comparison of indoor and outdoor calf housing systems using automated and manual feeding methods and their effect on calf health,behavior, growth,and labor

Housing and feeding are integral to calf rearing, and must meet calf needs while remaining functional for the farmer. This study compared health, behavior, growth, and labor requirements of calves housed in groups indoors and fed via an automatic or manual milk feeding system compared to calves manually fed in individual or group hutches outdoors. Seventy-six (49 Holstein Friesian [HF] and 27 HF × Jersey) dairy heifer calves were balanced for birth weight (35.2 ± 4.95 kg), birth date (1 February ± 7.2 d) and breed. The experiment was a randomized block design with four treatments; 1) indoor group housing with automated feeding (IN_AUTO; 12 calves per pen), 2) indoor group housing with manual feeding (IN_MAN; 12 calves per pen), 3) outdoor group hutch with manual feeding (OUT_G_MAN; 8 calves per pen), and 4) outdoor individual hutch with manual feeding (OUT_I_MAN; 6 calves: 1 per pen). Calves in OUT_treatments moved outdoors at 18 d (± 5.9 d). Each treatment was replicated once. Milk allowance increased gradually from 6 to 8 L/day (15% reconstitution rate) with ad libitum fresh water, concentrates, and hay offered from 3 d old. Gradual weaning occurred at 8 wk old. Measurements were divided into period 1; before movement outdoors, and period 2; after movement outdoors. Health was similar among treatments, regardless of period, with the most frequent score being zero (i.e., healthy). Summarized, standing and lying were observed 24.3% and 29.8%, respectively, in OUT_I_MAN calves, compared to 8.0% and 49.1%, for the other systems, which were similar. No difference in bodyweight (BW) existed between treatments, except at weaning where BW was lower for OUT_I_MAN (67.4 ± 2.84 kg) compared to IN_MAN (74.2 ± 2.01 kg), and day 102 where OUT_I_MAN (94.1 ± 2.85 kg) were lighter than IN_AUTO (101.1 ± 2.10 kg) (P = 0.047). Total labor input was greatest for OUT_I_MAN (00:02:02 per calf per day; hh:mm:ss) and least for IN_AUTO (00:00:21 per calf per day) (P < 0.001). The labor for feeding (00:00:29 per calf per day), feeding inspection (00:00:10 per calf per day), and cleaning equipment (00:00:30 per calf per day) was greatest for OUT_I_MAN. All calves showed good health and growth patterns. Differences in behavior expressed by calves in the OUT_I_MAN, compared to other treatments may indicate compromised welfare. Thus, although outdoor group hutches do not negatively impact calves, indoor housing, particularly using automated feeders, can improve labor efficiency.     

Effects of continuous and periodic feeding by electronic feeders on accuracy of measuring feed intake information and their genetic association with growth performances

The objective of the study was to analyse the effects of different feeding and recording regimes by electronic feeding stations on growth rate, feed intake and feed intake behaviour. A total of 563 boars of three dam lines were group‐penned and fed ad libitum during an age‐dependent performance test. Of this total, 219 were fed during the entire performance test period of 10 weeks by electronic feeding stations (continuous feeding regime). Based on this feeding regime, no differences were found in feed intake and feed intake behaviour when considering information from either all weeks or every second week. A second group of 344 boars was fed during test weeks 1, 3, 5, 7 and 9 by electronic feeding stations and in the remaining weeks feed was supplied using conventional feeders without recording feed intake (periodic feeding regime). Growth rate and backfat thickness were non‐significantly different between feeding regimes, but significant differences were found between the periodic and continuous feeding regime in daily feed intake (2218 versus 2544 g) and behavioural traits such as visits per day (5.4 versus 7.2), time per day (57.1 versus 63.5 min), time per visit (12.5 versus 11.4 min), and feed intake rate (41.5 versus 43.4 g). Furthermore, the effect of test days on estimation of feed intake was analysed. In the periodic feeding regime, only the exclusion of the first 2 days of each week with recording showed a significant improvement of prediction of feed intake. Based on this daily information, differences in feed intake between feeding regimes decreased (2492 versus 2592 g), whereas visits per day, time per visit and feed intake per visit still differed significantly between periodic and continuous feeding regimes (5.7 versus 7.2; 13.5 versus 11.6 min; and 541 versus 467 g, respectively). Differences were also observed for genetic correlations among behavioural traits between the periodic and continuous feeding regimes, e.g. for daily feed intake and feed intake rate with time per visit (0.47 versus –0.07; –0.16 versus –0.57) and with feed intake per visit (0.81 versus 0.17; 0.58 versus –0.08). Based on the present results a continuous feeding regime was recommended in order to avoid the effect of repeated adaptation. This feeding regime also delivers a greater amount of reliable information and increases the accuracy of prediction of feed intake capacity. In case of limited test capacities and measuring feed intake in particular periods, the first two test days of each period with recording should be excluded to obtain more reliable feed intake information.     

Estimates of genetic parameters for feed intake, feeding behavior, and daily gain in composite ram lambs

Our objective was to estimate genetic parameters for feed intake, feeding behavior, and ADG in composite ram lambs ((1/2) Columbia, (1/4) Hampshire, (1/4) Suffolk). Data were collected from 1986 to 1997 on 1,239 ram lambs from approximately 11 to 17 wk of age at the U.S. Meat Animal Research Center near Clay Center, NE. Feeding equipment consisted of an elevated pen with an entrance chute that permitted access to the feeder by only one ram lamb at a time, with disappearance of feed measured by an electronic weighing system. Ram lambs were grouped 11 per pen from 1986 to 1989, and nine per pen from 1990 to 1997. Data were edited to exclude invalid feeding events, and approximately 80% of the data remained after edits were applied. Traits analyzed were daily feed intake (DFI), event feed intake (EFI), residual feed intake (RFI), daily feeding time (DFT), event feeding time (EFT), number of daily feeding events (DFE), and ADG. Feed intake traits of DFI and EFI had estimated heritabilities of 0.25 and 0.33, respectively, whereas estimated heritability of RFI was 0.11. Heritability estimates for feeding behavior traits, including DFT, EFT, and DFE, ranged from 0.29 to 0.36. Average daily gain had an estimated heritability of 0.26. Genetic correlations were positive between all pairs of traits, except for RFI and ADG, and that estimate was essentially zero. Phenotypic correlations were generally similar to genetic correlations. Genetic correlations were large (0.80) between DFI and ADG, intermediate between DFI and RFI (0.61) and between DFT and DFE (0.55), and low (0.17 to 0.31) for the other pairs of traits, with the exception of RFI and ADG (-0.03). Genetic correlations between behavioral traits were greater than correlations between behavioral traits and measures of feed intake or ADG; however, selection for ADG and/or feed intake would be expected to cause some changes in feeding behavior.     

Relationship between feeding behaviour and feed intake of dairy cows depending on their parity and milk yield

To investigate the relationship between the parameters of feeding behaviour and feed intake, 70 lactating dairy cows (23 primiparous and 47 multiparous) were monitored from the 2nd to 15th week of lactation. Data were collected by using an automatic feeder and electronic identification of individual cows from 10 July 2005 to 16 January 2006. The resulting data of the cows in primiparous and multiparous condition were categorised into groups based on the mean of their milk yield over the first 15 weeks of lactation: primiparous cows with below-average milk yield (LP) and above-average milk yield (HP) with an average of 28.44 and 34.31 kg energy-corrected milk (ECM) per day, respectively, and multiparous cows with below-average milk yield (LM) and above-average milk yield (HM) with an average of 38.70 and 44.49 kg ECM per day, respectively. The parameters of feeding behaviour were calculated based on the estimated meal criterion from pooled data. Parity, level of milk yield, and day had significant effects on some of characteristics of feeding behaviour and feed intake parameters. There was no significant difference in meal duration either between primiparous and multiparous cows or between LP and HP. However, a significant difference between LM and HM was observed. Cows in HM had shorter feeding times but a larger meal size, higher DMI, and feeding rate. Moreover, these cows displayed a stronger correlation between meal duration, daily mealtime and daily feed intake (r = 0.37 and 0.50, P < 0.001, respectively) than any other cow or group of cows of the study. Meal duration, daily mealtime, meal size and daily DMI increased on average about 32%, 20%, 35%, and 22% respectively, considering all milk yield groups from the 2nd to 15th week of lactation.     

Feeding behavior in primiparous lactating sows: impact of a high-fiber diet during pregnancy

Voluntary feed intake of hyperprolific sows can be insufficient to cover the requirements for milk production and maintenance of body condition. A bulky diet fed during pregnancy is known to prepare sows for an ad libitum feed supply after parturition as shown by the increased feed intake during lactation. The aim of this study was to investigate the feeding behavior of young sows during their first lactation to evaluate the further impact of the feeding experience acquired during pregnancy, through the addition of dietary fiber in the diet. Analysis of the feeding pattern and the profile of feed intake tested the hypothesis that lactating sows would exhibit different feeding strategies depending on the diet during pregnancy. During pregnancy, 24 primiparous sows (Large White x Landrace) were offered either 2.4 kg of a control diet/d containing 3.16% crude fiber or 2.8 kg of a high-fiber diet/d containing 12.42% crude fiber. All sows received 33 MJ of DE/d. From the first day postpartum until weaning, all sows were offered the same lactation diet ad libitum. The feeding pattern during lactation was recorded as ADFI, meal frequency, and meal size. In lactation, the ADFI did not differ according to the treatment. Compared with control sows, high-fiber sows consumed their diet in more (P < 0.05) but smaller meals (P < 0.05). In both treatments, ADFI and the number of daily meals increased over weeks of lactation (P < 0.001). All sows presented a strong diurnal and bimodal feeding activity evolving toward 2 distinct feeding periods occurring from 0500 to 0900 and from 1400 to 1800 and accounting for 0.64 of the total daily feed intake during the third week of lactation. The provision of a fibrous diet during pregnancy pointed out the role of an early feeding experience on the development of feeding behavior during the first reproductive cycle.     

Robustness scores in fattening pigs based on routinely collected phenotypes: determination and genetic parameters

The objective was to determine operational proxies for robustness based on data collected routinely on farm that allow phenotyping of these traits in fattening pigs, and to estimate their genetic parameters. A total of 7,256 pigs, from two Piétrain paternal lines (Pie and Pie NN), were tested at the AXIOM boar testing station (Azay-sur-Indre, France) from 2019 to 2021. During the fattening period (from 75 to 150 d of age), individual performance indicators were recorded (growth, backfat, loin depth, feed intake, and feed conversion ratio [FCR]) together with indicators such as insufficient growth, observable defect, symptoms of diseases, and antibiotic and anti-inflammatory injections. These indicators were combined into three categorical robustness scores: R1, R2, and R3. Genetic parameters were estimated using an animal linear model. The robustness score R2 (selectable or not selectable animal) that combined information from status at testing and mortality had the highest heritability estimates of 0.08 ± 0.03 for Pie NN line and a value of 0.09 ± 0.02 for Pie line, compared with traits R1 and R3. The score R3 that combines information from the score R2 with antibiotic and anti-inflammatory injections presented slightly lower heritability estimates (0.05 ± 0.02 to 0.07 ± 0.03). Genetic correlations between R2 and R3 were high and favorable (0.93 ± 0.04 to 0.95 ± 0.03) and R2 and R3 can be considered identical with regard to the confidence interval. These two robustness scores were also highly and favorably genetically correlated with initial body weight and average daily gain, and unfavorably correlated with daily feed intake (ranging from 0.73 ± 0.06 to 0.90 ± 0.08). Estimates of genetic correlations of R2 and R3 with backfat depth and raw FCR (not standardized between starting and finishing weights) were moderate and unfavorable (0.20 ± 0.13 to 0.46 ± 0.20). A part of these genetic correlations, that are of low precision due to the number of data available, have to be confirmed on larger datasets. The results showed the interest of using routine phenotypes collected on farm to build simple robustness indicators that can be applied in breeding.     

Heat production, eating behavior and milk yield of lactating cows fed two rations differing in roughage content and digestibility under heat load conditions

The objective of this study was to measure the effect of feeding two total mixed rations (TMRs), differing in their roughage content and in vitro dry matter digestibility, on the respiratory rate, body temperature, eating behavior and energy balance of lactating cows. The partitioning of metabolizable energy intake (MEI) between heat production (HP) and retained energy (RE) of cows held under heat load conditions was measured. Forty-two lactating cows were divided into two similar sub-groups, each of 21 animals, and were fed either a control (CON) ration containing 18% roughage neutral detergent fiber (NDF) or an experimental (EXP) TMR that contained 12% roughage NDF and used soy hulls as partial wheat silage replacer. The in vitro DM digestibility of the CON and EXP TMRs was 75.3 and 78.6%, respectively (P < 0.05). The EXP diet reduced rectal temperature and respiratory rate of the cows while increasing their number of meals per day by 32.7% as compared with the CON fed cows, and these meals were shorter in duration and were eaten faster. The EXP diet increased total DM intake from 19.6 to 21.5 kg/cow/d, milk yield from 32.3 to 34.6 kg, and yield of energy corrected milk from 30.9 to 32.2 kg, as compared with the CON group. Cows fed the EXP TMR had increased RE in milk and body tissue, as compared with the CON group, but the diets had no effect on the measured HP that was maintained similar (121 vs. 127 MJ/cow/d) in the two groups. The measured MEI (MEI = RE + HP) and the efficiency of MEI utilization for RE production, were similar in the two dietary groups.     

Genetic parameters for dry matter, energy and protein intake, and their relationships with performance and carcass traits in Japanese Black cattle

Genetic parameters for feed intake and performance traits of 514 bulls and carcass traits of 22 099 of their progeny, and the relationships of measures of feed intake with performance and carcass traits were estimated. Feed intake traits were dry matter intake (DMI), concentrate intake (CONI), roughage intake, ratio of roughage intake to DMI, metabolizable energy intake (MEI) and digestible crude protein intake (DCPI). Performance traits included daily gain, metabolic weight, live weight at the end of test, dry matter conversion ratio and residual feed intake. Progeny carcass traits were carcass weight, percentage of meat yield, rib eye area (REA), subcutaneous fat, marbling score, meat colour (MCS), fat colour (FCS) and meat quality grade. All the feed intake and performance traits were moderately heritable. The heritabilities for REA and MCS were moderate, and that for FCS was low, while those for the other carcass traits were high. Selection against DMI, CONI and DCPI would reduce excessive intake of feed, but would have undesirable effects on growth and most of the carcass traits. Selection against MEI would lead to improvements in feed efficiency and growth traits. Selection against DCPI would also improve feed efficiency; however, responses in growth traits would decrease. Results indicate that selection against MEI might be better than any other measures of feed intake to improve feed efficiency with simultaneous improvement in growth and most of the carcass traits.     

Genetic analysis of behavior traits in swine production

Estimates of genetic parameters related to pig behavior under stressful situations are required before selection programs can be designed to produce more docile pigs. Pig behavior was evaluated in a pedigreed Landrace–Duroc–Yorkshire composite population. Piglets were evaluated for their response to handling at 1 d of age (n=11069), being placed on their back for 60 s at ~24 d of age (n=975), and being confined in a scale while backfat measurements were being collected (n=9035). Feeding behavior was monitored in a growing–finishing facility (n=1162) including preferences for feeding positions. Feeders were placed along a fence with one end adjacent to a gate (gate-end) and the other end open. An animal model was fitted to the data using WOMBAT where litter was included for d 1 activity scores and backtest traits. Fixed effects of sex, pen/year-season/date of collection in all analyses along with scorer (d 1 activity score) and a covariate of age (d 154 weight and backfat). Multiple trait models were fit to estimate genetic covariances among traits. All estimates of heritability were significantly different than zero. Activity scores and backtest traits had the lowest estimates of heritability (0.15–0.19), measures of feeding behavior were more variable (0.16–0.60) while production data had high heritabilities (>0.5). Genomic heritability estimates were similar to standard heritability estimates for most traits, except traits measured at a young age. All traits measured during the backtest had strong genetic correlations and similar estimated heritability. Among feeding behavior traits, number of meals/d and average meal length were highly correlated with total daily meal time. In addition, animals that preferred to eat alone avoided the open-end position at the feeder. The only behavioral traits with genetic correlations significantly different from zero with production traits were associated with feeding behavior where animals that ate longer meals and spent more time at the feeder/d tended to be heavier and fatter at 154 d. In addition, animals that ate more meals/d were fatter and animals that preferred the gate-end position of the feeder were heavier. Pigs with more reactive personalities tended to eat fewer meals/d, each longer in duration, and they preferred the gate-end feeder position. The measures of pig behavior studied were heritable and selection for more docile pigs should not have large detrimental effects on performance.     

Genetic and phenotypic relationships of feeding behavior and temperament with performance, feed efficiency, ultrasound, and carcass merit of beef cattle

Feeding behavior and temperament may be useful in genetic evaluations either as indicator traits for other economically relevant traits or because the behavior traits may have a direct economic value. We determined the variation in feeding behavior and temperament of beef cattle sired by Angus, Charolais, or Hybrid bulls and evaluated their associations with performance, efficiency, and carcass merit. The behavior traits were daily feeding duration, feeding head down (HD) time, feeding frequency (FF), and flight speed (FS, as a measure of temperament). A pedigree file of 813 animals forming 28 paternal half-sib families with about 20 progeny per sire was used. Performance, feeding behavior, and efficiency records were available on 464 animals of which 381 and 302 had records on carcass merit and flight speed, respectively. Large SE reflect the number of animals used. Direct heritability estimates were 0.28 +/- 0.12 for feeding duration, 0.33 +/- 0.12 for HD, 0.38 +/- 0.13 for FF, and 0.49 +/- 0.18 for FS. Feeding duration had a weak positive genetic (r(g)) correlation with HD (r(g) = 0.25 +/- 0.32) and FS (r(g) = 0.42 +/- 0.26) but a moderate negative genetic correlation with FF (r(g) = -0.40 +/- 0.30). Feeding duration had positive phenotypic (r(p)) and genetic correlations with DMI (r(p) = 0.27; r(g) = 0.56 +/- 0.20) and residual feed intake (RFI; r(p) = 0.49; r(g) = 0.57 +/- 0.28) but was unrelated phenotypically with feed conversion ratio [FCR; which is the reciprocal of the efficiency of growth (G:F)]. Feeding duration was negatively correlated with FCR (r(g) = -0.25 +/- 0.29). Feeding frequency had a moderate to high negative genetic correlation with DMI (r(g) = -0.74 +/- 0.15), FCR (r(g) = -0.52 +/- 0.21), and RFI (r(g) = -0.77 +/- 0.21). Flight speed was negatively correlated phenotypically with DMI (r(p) = -0.35) but was unrelated phenotypically with FCR or RFI. On the other hand, FS had a weak negative genetic correlation with DMI (r(g) = -0.11 +/- 0.26), a moderate genetic correlation with FCR (r(g) = 0.40 +/- 0.26), and a negative genetic correlation with RFI (r(g) = -0.59 +/- 0.45). The results indicate that behavior traits may contribute to the variation in the efficiency of growth of beef cattle, and there are potential correlated responses to selection to improve efficiency. Feeding behavior and temperament may need to be included in the definition of beef cattle breeding goals, and approaches such as the culling of unmanageable cattle and the introduction of correct handling facilities or early life provision of appropriate experiences to improve handling will be useful.     

Direct and maternal genetic parameters for measures of feed consumption and feed efficiency in young male Japanese Black cattle

Direct and maternal genetic parameters for measures of feed consumption and feed efficiency were estimated using data recorded on 514 performance tested young male Japanese Black cattle during the period from 1978–2004. Measures of feed consumption were daily feed intake, concentrate intake, ratio of roughage intake to feed intake, total digestible nutrient intake, digestible crude protein intake (DCPI) and metabolizable energy intake. Feed efficiency traits included feed conversion ratio (FCR), total digestible nutrient conversion ratio (TCR), digestible crude protein conversion ratio (DCR) and residual feed intake. Data were analyzed using three alternative animal models (including direct and direct plus maternal genetic effects (including or excluding covariance between direct and maternal genetic effects)). The direct heritability estimates for all the measures of feed consumption and feed efficiency were moderate to high, suggesting that sufficient genetic variation exists in these traits which should respond to selection. All the measures of feed consumption were genetically more strongly correlated with residual feed intake than with other measures of feed efficiency. Maternal heritability estimates for DCPI, FCR and TCR were not significantly different from zero, while the corresponding estimates for all the studied traits were low (ranged from 0.07 to 0.24). The estimates of direct heritability for measures of feed consumption were reduced up to 34% when maternal genetic effect was considered in the model. An antagonistic relationship existed between direct and maternal genetic effect (r_am) for FCR and DCR, which biased the estimates of direct heritability downwards. The results indicate that maternal effects play an important role in measures of feed consumption and most of the feed efficiency traits, which should be accounted for these traits in genetic evaluation system.