Number Of Feeder Visits Research Articles

159 Evaluation of Supplemental Feeding Behavior and Growth Performance in Katahdin Lambs Divergently Selected for Fecal Egg Count Estimated Breeding Value

Abstract Nutritional supplementation and genetic selection are potential methods to mitigate the impact of parasitism in sheep. Understanding feeding behavior of growing lambs divergently selected for parasite resistance using the fecal egg count (FEC) estimated breeding value (EBV) may help quantify the impact of supplementation and genetic selection on parasitism. The C-Lock, Inc Super SmartFeed system (feeder) allows measurement of individual lamb feed intake. The objective of this study was to evaluate the effect of FEC EBV selection on daily supplemental intake, average daily gain (ADG), supplemental feed:gain (S:G), frequency of feeder visits, and FEC. Over two years (Y1, Y2), Katahdin lambs divergently selected for FEC EBV (Y1: LowFEC, n = 27; HighFEC, n = 24. Y2: LowFEC, n = 37; HighFEC, n = 40) were fed for 8 weeks in Y1 and 5 weeks in Y2 at the Southwest Virginia Agricultural Research and Extension Center. Pasture-raised lambs were supplemented with a concentrate pellet (16% CP) ad libitum using the feeder with free choice hay in a dry lot post-weaning. Data analyses were performed by sampling period which was approximately every two weeks. Statistical analyses were performed using PROC Mixed SAS (SAS Institute, Cary, NC). In Y1, LowFEC lambs had less average FEC than HighFEC lambs (405.25 vs. 771.23 epg; P < 0.05). LowFEC lambs in Y2 tended to have less average FEC compared with HighFEC lambs (1,191.75 vs. 2,028.30 epg; P = 0.1). In Y1, LowFEC lambs had greater intake compared with HighFEC lambs (1.45 vs. 1.27 kg; P < 0.05). LowFEC lambs tended to have greater intake in Y2 (1.64 vs. 1.16 kg; P = 0.1). While ADG was not affected by FEC EBV type in Y1 (P > 0.70), LowFEC lambs in Y2 had increased ADG compared with HighFEC lambs (0.27 kg vs. 0.21 kg; P = 0.05). In both years, LowFEC lambs had numerically greater S:G compared with HighFEC lambs, but these differences were not significant (P > 0.1) due to greater variation around these means. Over both years, the number of feeder visits did not differ between LowFEC and HighFEC lambs (P > 0.1). Selection of sires for LowFEC EBV resulted in progeny with less FEC that had increased supplemental intake, but no difference in S:G compared with HighFEC progeny. In addition to improvements in parasite resistance, selection for FEC EBV may impact lamb feeding behavior in the post-weaning period.

Provision of lucerne in the diet or as a manipulable enrichment material enhances feed efficiency and welfare status for growing-finishing pigs

This research investigated the effects of including lucerne in a diet and as manipulable enrichment material on growing-finishing pig growth performance and behaviour. Forty-eight intact male Duroc × (Large White × Landrace) pigs with an initial live weight (LW) of 26.4 ± 2.32 kg (mean ± SD) were blocked by LW and randomly assigned to two dietary treatments (control vs lucerne), and two manipulable material treatments (without and with lucerne chaff for manipulable material). The barley and soybean meal-based control diet was formulated according to a commercial standard, while the lucerne diet replaced 100 g/kg of the barley and soybean oil in the control diet with lucerne chaff. The diets were formulated to have the same amount of digestible energy and apparent ileal digestible lysine. Manipulable material (lucerne chaff) was provided daily at 100 g/pig. Pigs had ad libitum access to diets via electronic feeders until they reached approximately 90 kg LW, at which time they were slaughtered. There were no interactions between dietary treatment and provision of manipulable material on pig production and behaviour. Feeding the lucerne diet reduced average daily feed intake, LW gain, feed intake per feeder visit, and feeding rate, but increased feed efficiency (P < 0.05). Access to manipulable material did not affect any growth traits, but the number of feeder visits per day was greater and the duration of visits to the feeder was lower in pigs that had access to lucerne chaff (P < 0.001). Compared to the other groups, pigs that consumed the lucerne diet or had access to manipulable material rested for a shorter duration but engaged in more social interactions and exploration behaviour. In conclusion, including 10% lucerne in growing-finishing diets improved feed efficiency and lucerne chaff appears to be an attractive enrichment source to pigs.

A New Approach to Detecting and Measuring Changes in the Feeding Behaviour Habits of Group-Housed Growing-Finishing Pigs.

Simple SummaryIt is known that feeding behaviour habits (FBHs) influence growing–finishing pigs’ performance and are modified by production conditions on a group scale. However, no methods are available to describe the evolution of the FBHs at the individual level over short- or long-term periods. This work presents two methods, i.e., repeatability (ratio between animal and total variance) and a new non-parametric approach named “maintenance”, which provides information at the individual level by typifying the individuals into classes and quantifying (%) the pigs that show similar FBHs. Both concepts were applied to six consecutive 14-day periods, throughout two trials of group-housed growing–finishing pigs under different environmental conditions and fed different physical feed forms (mash and pelleted). Both repeatability and maintenance indexes showed similar but not identical results, since they provide complementary information at the global and individual levels, respectively. The results indicate that the environmental conditions and physical feed form modified the repeatability and maintenance of most FBHs, except for the average daily feed intake. Moreover, since maintenance provides data at the individual level, this may be an interesting approach in further studies, for example, to analyse the influence of pen hierarchy on FBHs.The present work aims to estimate the methods of repeatability and of a new non-parametric approach based on typifying individuals into classes and quantifying (%) the pigs in a group that show similar feeding behaviour habits (FBHs) in consecutive periods (“maintenance”). Both methods were estimated over six consecutive 14-day periods in two trials of group-housed growing–finishing pigs (n = 60 each). The first trial started in summer and ended in autumn, and pigs were fed a pelleted diet (HT-P). The second trial started in spring and ended in summer, and the same diet was fed mash (TH-M). The average daily feed intake obtained the lowest repeatability and maintenance values, and it progressively decreased as pigs grew, independent of environmental conditions or physical feed form, whereas the maintenance and repeatability of the number of feeder visits and the visit size decreased when environmental conditions changed from temperate to hot, and mash-fed pigs had higher maintenance and repeatability values for the time spent eating than pellet-fed pigs. In conclusion, the new approach (maintenance) is a tool that is complementary to the classic repeatability concept and is useful for analysing the evolution of FBHs across periods of time at the individual level.

The effect of transition cow housing on lying and feeding behavior in Holstein dairy cows

The present study investigated the effect of straw yard housing during the dry period and 2 d of additional maternity pen housing postcalving on lying and feeding behavior and calving difficulty in Holstein dairy cows. In this study, 122 multiparous cows were moved to either a straw yard or into freestall housing 4 wk before their expected calving date. Cows that had been housed in straw yards stayed in the maternity pen for an additional 2 d after their calving day, but cows that had been housed in freestalls were moved to the general lactation group the morning after calving. Lying time, lying bouts, feeding time, number of feeder visits, feed intake, feeding rate, and assisted calvings were recorded. Observations were divided into 2 periods: precalving (the 4-wk dry period before calving) and postcalving (the day of calving and the 2 d after). During the precalving period, cows housed in straw yards showed a higher number of lying bouts but no difference in lying time compared with cows housed in freestalls. Cows that were housed longer in the straw-bedded maternity pen postcalving spent more time lying during the 2 d postcalving and had a higher number of lying bouts on the day of calving than cows moved to the freestall area on the day postcalving. Additionally, cows that were housed longer in the maternity pen had a slower feeding rate and longer total feeding time during the 2 d after calving than cows with a shorter stay in the maternity pen. We found no difference in the number of assisted calvings. This study suggests that straw yard housing during the dry period may facilitate the transition between standing and lying. Furthermore, the extended stay in the maternity pen postcalving increased lying time, the number of lying bouts, and feeding time, but decreased feeding rate compared with cows that were moved to the general lactation group on the day postcalving. These results suggest potential recovery benefits with an extended stay in a maternity pen postcalving. However, further studies are needed to separate the effects of housing in the dry period and the effects of an extended housing in individual maternity pens.

Genetic variation in residual feed intake is associated with body composition, behavior, rumen, heat production, hematology, and immune competence traits in Angus cattle1.

This experiment was to evaluate a suite of biological traits likely to be associated with genetic variation in residual feed intake (RFI) in Angus cattle. Twenty nine steers and 30 heifers bred to be divergent in postweaning RFI (RFIp) and that differed in midparent RFIp-EBV (RFIp-EBVmp) by more than 2 kg DMI/d were used in this study. A 1-unit (1 kg DM/d) decrease in RFIp-EBVmp was accompanied by a 0.08 kg (SE = 0.03; P < 0.05) increase in ADG, a 0.58 kg/d (0.17; P < 0.01) decrease in DMI, a 0.89 kg/kg (0.22; P < 0.001) decrease in FCR, and a 0.62 kg/d (0.12; P < 0.001) decrease in feedlot RFI (RFIf). Ultrasonically scanned depths of subcutaneous fat at the rib and rump sites, measured at the start and end of the RFI test, all had strong positive correlations with RFIp-EBVmp, DMI, and RFIf (all r values ≥0.5 and P < 0.001). Variation in RFIp-EBVmp was significantly correlated (P < 0.05) with flight speed (r = -0.32), number of visits to feed bins (r = 0.45), and visits to exhaled-emission monitors (r = -0.27), as well as the concentrations of propionate (r = -0.32) and valerate (r = -0.31) in rumen fluid, white blood cell (r = -0.51), lymphocyte (r = -0.43), and neutrophil (r = -0.31) counts in blood. RFIp-EBVmp was also correlated with the cellular immune response to vaccination (r = 0.25; P < 0.1) and heat production in fasted cattle (r = -0.46; P < 0.001). Traits that explained significant variation (P < 0.05) in DMI over the RFI test were midtest metabolic-BW (44.7%), rib fat depth at the end of test (an additional 18%), number of feeder visits (additional 5.7%), apparent digestibility of the ration by animals (additional 2.4%) and white blood-cell count (2.1%), and the cellular immune response to vaccine injection (additional 1.1%; P < 0.1), leaving ~23% of the variation in DMI unexplained. The same traits (BW excluded) explained 33%, 12%, 3.6%, 3.7%, and 3.1%, and together explained 57% of the variation in RFIf. This experiment showed that genetic variation in RFI was accompanied by variation in estimated body composition, behavior, rumen, fasted heat production, hematology, and immune competence traits, and that variation in feedlot DMI and RFIf was due to differences in BW, scanned fatness, and many other factors in these cattle fed ad libitum and able to display any innate differences in appetite, temperament, feeding behavior, and activity.

Relationship between inclusion level of Vachellia tortilis leaf meal and behavioral activities of finishing pigs.

ObjectiveThe study was conducted to establish a relationship between inclusion level of Vachellia tortilis (V. tortilis) leaf meal and time spent on different behavioral activities by finishing pigs.MethodsA total of forty-eight male Large White×Landrace finishing pigs with a mean (±standard deviation) body weight of 63.8±3.28 kg aged 14 wks were assigned to individual pens in a completely randomized design. Pigs were fed on diets containing 0, 30, 60, 90, 120, and 150 g/kg dry matter of V. tortilis leaf meal ad libitum with fresh water provided throughout the trial. There were eight pigs in each experimental diet. The behavior of pigs was observed for three wks twice a wk from 0600 to 1800 h using six closed circuit television cameras.ResultsIncreasing levels of V. tortilis leaf meal caused a linear decrease (p<0.05) in time spent eating, lying down and the number of visit to the feeder. Time spent standing and biting objects increased linearly (p<0.05) with increasing inclusion level of V. tortilis leaf meal. The was a negative linear relationship (p<0.05) between condensed tannins versus time spent eating, lying down and number of feeder visits. Condensed tannins showed a positive linear relationship (p<0.05) with time spent standing and biting objects. Neutral detergent fiber caused a linear decrease (p<0.05) in number of feeder visits, time spent eating, time spent standing.ConclusionInclusion level of V. tortilis leaf meal reduces time spent eating, lying down and the number of feeder visit while prolonging time spent standing and biting of objects. Condensed tannins and dietary fiber are among nutritional factors affecting behavioral activities displayed by finishing pigs.

The effect of deep straw versus cubicle housing on behaviour during the dry period in Holstein cows

The present observational study assessed the effect of deep straw bedding compared to cubicles during the dry period on lying-, feeding- and agonistic behaviour in Holstein cows. A total of 74 primi- (heifers) and multiparous cows were moved either onto deep straw bedding (DS) or into cubicle housing (CS) 4 wk before the expected calving date and were observed for 21 consecutive days. Throughout the 21 d lying time and the number of lying bouts were recorded using automated accelerometers while feeding time, the number of feeder visits and feed intake was recorded using automatic feed bins. All variables were averaged by week. The transition time from lying to standing was obtained by averaging five randomly selected standing up events on d 7 prior to the actual calving date while the number of failed standing attempts was obtained by following the cows standing up bouts throughout all of d 7 prior to the actual calving date. The frequency of agonistic behaviour was obtained from 7 h of continuous video recordings on d 21 and 7 (or 8) before the actual calving date. Lying time was not affected by treatment but DS cows had a higher number of lying bouts and a shorter transition time between lying and standing compared to CS cows. Primiparous cows had a higher number of lying bouts compared to multiparous cows. There were no treatment differences in feeding behaviour but multiparous cows spent more time feeding and increased their feed intake more across weeks compared to primiparous cows. Cows housed in DS initiated more agonistic behaviour compared to CS cows at d 7 (or 8) before calving while no difference between treatments was seen at 21 d before calving. These results suggest that deep straw bedding facilitates the transition between lying and standing but may increase agonistic behaviour.

Sex differences in cattle feed consumption during winter by the Spotless Starling (Sturnus unicolor)

The Spotless Starling (Sturnus unicolor) is considered to be a pest in several areas within its geographical range, because it feeds on large amounts of cattle feed in farms, causing important economic losses. In order to better understand the bird's behaviour in relation to this food resource, we studied individuals that exploited cattle feed in a commercial cattle farm over the winter season (December to March). The number of visits by the birds to feeders and the amount of feed consumed gradually increased from December to February. Between February and March, when the starlings prepare for the breeding season and build their nests, both the number of feeder visits and the rate of cattle feed consumption increased. These increases were greatest among female starlings, probably because females must consume more food to meet the energy demands of reproduction. The economic losses caused by the starlings during winter could be reduced by: (i) increasing efforts to restrict access to cattle feed, especially during the pre-reproductive period (February to March) and/or (ii) controlling the starling population, focusing on females, as they cause more damage than males.

Tits recognize the potential dangers of predators and harmless birds in feeder experiments

Accurate recognition of a predator is the necessary precondition for adequate antipredatory behaviour. We used feeder experiments to examine whether birds adopt the appropriate antipredatory response according to the level of threat posed by predators. The results support the idea that the tits made a decision on the threat level. The tits distinguished among equally sized obligatory predators (sparrowhawk, kestrel), an occasional predator (jay) and a harmless bird of similar size (pigeon) and a smaller harmless bird (thrush). The presence of both birds of prey was associated with a considerable reduction in the number of feeder visits when compared with the harmless birds. The number of visits to the feeder that had a dummy jay positioned on it did not significantly differ for harmless birds or for predators. Different sizes of harmless birds did not influence the tits’ behaviour. The increasing risk lowered not only the number of visits to the feeder but also the success of the visit, pecking rate, and the direction of arrival to the feeder. Generally, birds assessed the risk during food searching, evaluated the situation, and adapted their behaviour accordingly.

Invited review: Feeding behavior of goats1,2

Factors influencing the feeding behavior of goats include grazing management practices, type of vegetation and season, breed and stage of production, group size, and properties of diets fed in confinement. Considerable information has been gathered from visual observation during daylight. However, tools are now available to characterize the feeding behavior of goats while grazing and while in confinement throughout the day. Global positioning system collars can be used to assess horizontal and vertical distances traveled, up or down position of the head, and movement within pasture or rangeland areas. A commercially available leg activity monitor allows estimation of the number of steps and time spent standing, lying, and moving rapidly without grazing. However, these measurements do not directly determine grazing. Therefore, prediction equations based on visual observation must be developed. Classification tree analysis is a robust method in developing these equations because the decision tree can be pruned or expanded to provide the best fit. Another equipment system determines time spent eating, ruminating, and remaining idle from the pattern of jaw movement. In addition to use of n-alkanes as internal markers to estimate digestibility, their profile can provide an indication of the botanical composition of the selected diet. Automated feeding systems for confined goats permit determinations such as number of feeder visits and meals, eating time, and rate and pattern of feed intake. Heart rate measured while goats are in normal production settings can be used to predict total energy expenditure through multiplication by energy expenditure per heartbeat of individual animals. To partition the activity energy cost, an estimate of ME intake or measures of changes in body energy status and milk energy yield are needed to determine other sources of heat to be subtracted from total energy expenditure. These methods create the opportunity to gain a fuller understanding of factors influencing the feeding behavior of goats and the relationships with levels and efficiencies of production.

Effects of feeding method, diet nutritive value and physical form and genotype on feed intake, feeding behavior and growth performance by meat goats

Thirty-two F1 Boer × Spanish (28.7 ± 0.49 kg) and 40 3/4 Boer–1/4 Spanish (31.9 ± 0.47 kg) wethers, approximately 5 months of age, were used to compare feeding systems with different dietary treatments. Feeding systems were Calan gates and automated feeding units allowing one animal to consume feed at a time. Two diets included concentrate (C) and two were dehydrated alfalfa (A), fed pelletized (P) or loose (L). The main effect of feeding method was not significant for any variable. There was an interaction in DM intake (DMI) involving feeding method, diet, and genotype, which indicated that with a concentrate diet, regardless of physical form, DMI was not influenced by feeding method. Main effect dietary treatment means (1.78, 1.67, 2.04, and 1.70 kg for C-P, C-L, A-P, and A-L, respectively; S.E. = 0.030) indicated that pelletizing had a slightly greater effect on DMI with A versus C. ADG was lowest among treatments for A-L (212, 205, 190, and 157 g for C-P, C-L, A-P, and A-L, respectively; S.E. = 8.9), and ADG:DMI was greater for C versus A (127, 120, 94, and 94 g/kg for C-P, C-L, A-P, and A-L, respectively; S.E. = 7.8). Both ADG and ADG:DMI were similar between genotypes. For wethers subjected to automated feeding units, the number of feeder visits was lowest among diets ( P < 0.05) for C-P (23.1, 31.2, 35.7, and 35.7 per day; S.E. = 2.00); total feeder occupancy time per animal ranked ( P < 0.05) C-P < A-P < C-L and A-L (74, 130, 105, and 122 min/day; S.E. = 6.8), and rate of DMI was greater for P than for L diets (24.6, 12.9, 22.0, and 13.7 g/min for C-P, C-L, A-P, and A-L, respectively; S.E. = 3.89). In summary, meat goats can markedly vary feeding behaviors in response to different diet types and forms; however, there appear limits to such changes, as exemplified by lowest ADG for A-L. Calan gates and automated feeding systems appear similar in the ability to compare growth performance with treatments such as the concentrate-containing diets and genotypes of this experiment. Pelletizing does not seem to affect growth performance with diets consisting of appreciable concentrate. Effects of pelletizing on growth performance of meat goats consuming forage diets may be attributable to change in level of feed intake, without impact on efficiency of feed utilization.

Effects of the number of yearling Boer crossbred wethers per automated feeding system unit on feed intake, feeding behavior and growth performance

Thirty-six growing Boer × Spanish wethers (initial BW of 30 ± 0.7 kg) were used in an 82-day experiment to determine effects of the number of animals per automated feeding system (NPF; 6, 8, 10 and 12), allowing consumption by only one animal at a given time, on intake of a 50% concentrate pelletized diet (9.2 MJ/kg ME, DM basis), feeding behavior and growth performance. During the entire experiment DM intake (1454, 1513, 1596 and 1374 g/day) and BW gain (156, 167, 181 and 136 g/day for 6, 8, 10 and 12 NPF, respectively) were affected by NPF quadratically ( P < 0.05), although gain efficiency (ADG:DM intake) was similar among NPF. The number of feeder visits (17.5, 17.1, 17.9 and 18.7) and meals (8.9, 9.0, 9.3 and 8.9) were similar among NPF, although feeder occupancy per day (97.8, 73.2, 83.0 and 71.7 min), visit (5.8, 4.4, 5.0 and 3.8 min) and meal (11.2, 8.2, 9.2 and 8.1 min for 6, 8, 10 and 12 NPF, respectively) decreased linearly with increasing NPF ( P < 0.05). The rate of DM consumption relative to feeder occupancy time plateaued as NPF increased to 8 (linear and quadratic changes, P < 0.05; 14.6, 24.9, 21.5 and 23.1 g/min for 6, 8, 10 and 12 NPF, respectively). In conclusion, with these diet and animal characteristics, 8 or 10 wethers per automated feeder appear appropriate for achieving unrestricted growth performance.

Weighing affects short-term feeding patterns of growing-finishing pigs

Data from two experiments were analyzed to determine the effect of weighing on the feeding patterns of growing-finishing pigs. Pigs had reduced feed intake on the day of weighing compared to before and after the weigh day through reduction in either feed intake per visit or number of feeder visits. Key words: Pig, feeding patterns, weighing

Effect of group size and feeder type on growth performance and feeding patterns in finishing pigs.

The effects of four group sizes (2, 4, 8, and 12 pigs per pen) and two single-space feeder types (conventional and electronic feed intake recording equipment [FIRE]) on feed intake, growth performance, and feeding patterns were determined in 208 crossbred finishing pigs (equal numbers of barrows and gilts) between 84.4 (SD = 0.81) to 112.8 (SD = 1.08) kg BW over a 4-wk period. Pigs were given ad libitum access to a corn-soybean meal-based diet (15.9% CP; 0.79% lysine; 3,328 kcal ME/kg). The floor space allowance was 0.9 m2/pig for all treatments. Growth rates were not different for the two feeder types; however, feed intake was lower and gain:feed ratio higher for pigs on the FIRE feeders (P < 0.01). Feed intake, growth rate, and gain:feed ratio were not different (P > 0.05) among the group sizes. Number of feeder visits per day decreased and feed intake per visit, feeder occupation time per visit, feed consumption rate, and percentage of time the feeder was occupied increased with group size (P < 0.05). Feed intake per visit had the strongest correlation with daily feed intake (r = 0.54; P < 0.01) and was negatively correlated with gain:feed ratio (r = -0.38; P < 0.01). However, the correlations between growth performance and other feeding pattern traits were relatively weak (r < or = 0.30). As group size increased, diurnal variation in number of feeder visits and feed consumed per hour decreased. There was no difference in time spent sitting and standing between the two feeder types. The proportion of time spent eating was generally lower for the larger groups on both feeders. The proportion of time spent lying was similar across group sizes for pigs on the conventional feeders but was greater for pigs in the larger groups on the FIRE feeders. This study suggests that finishing pigs can maintain feed intake and growth rate by changing feeding behavior as group size increases from 2 to 12.

The effects of changing straw provision on the feeding behaviour and activity of growing pigs given food through single-space feeders

AbstractIn a previous experiment the provision of straw to group-housed pigs increased the number of daily feeder visits. This effect of straw is comparable with conditions of reduced social competition for access to the feeder. The aim of this experiment was to investigate if changing straw provision within a pen resulted in similar and reversible effects in this behaviour. One hundred and twenty male pigs (41·1 (s.e. 0·43) kg) were used in three blocks each of four pens of 10 pigs. In each block of 42 days duration one pen had no straw throughout (treatment 1); one pen had no straw for 21 days (period 1) followed by straw for 21 days (period 2) (2); one pen had straw followed by no straw (3) and one pen had straw throughout (4). The pens were situated in a naturally ventilated building with light from 06.00 to 20.00 h. Each pen had a kennel, a lying area and a single-space computerized feeder for recording feeding behaviour. The pigs’ activity was recorded on video in the 2nd and 5th weeks of each block. The number of feeder visits was slightly higher for pigs with straw (1: 9·69 v. 4: 10·46) but this was not significant (P &gt; 0·05). The effect was more marked for treatment 2 where the visits increased (P &lt; 0·01) from period 1 (8·52) to period 2 (10·64) and for treatment 3 where they decreased (11·20 v. 10·10). Pigs without straw (treatment 1) spent more time in the kennel than those with straw (treatment 4) (P &lt; 0·05). For treatment 2 the proportion of time spent in the kennel fell from 0·607 in period 1 to 0·288 in period 2 (P &lt; 0·01). There was a general trend for more activity and more lying outside the kennel when straw was provided. The effect of straw provision was not as marked as that seen previously; nevertheless changing straw provision (treatments 2 and 3) did result in an increase in feeder visits with straw, probably related to the increase in general activity and lying outside in the area adjacent to the feeder.

Evaluation of Systems for Feeding Supplemental Concentrate to Cows in Groups

A herd of 211 Holstein cows plus heifers calving subsequently was stratified into equal performance groups that were assigned randomly to three feeding system subherds fed for 68 wk: 1) bunk-fed silage mixture plus concentrate individually via transponder control; 2) one-group total mixed ration; and 3) a two-group total mixed ration system with respective ratios of forage: concentrate: 1) 48:52, 2) 56:44, and 3) 55:45 with 42:58 for the first 24 wk of lactation and 72:28 for the remainder. Respective average dry matter intakes (kg/cow per day) for the three feeding systems were forage 8.6, 10.3, and 10.1 and concentrate 9.3, 8.0, and 8.3.Cows fed concentrate via transponder control produced significantly more milk than cows in the one- or two-group total mixed ration systems, 2.7 and 3.8 kg/cow per day. Calculated intakes of net energy lactation (Meal/cow per day) were 29.0, 28.8, and 29.1 for the three subherds, but relative to milk energy output, corresponding efficiencies were 61.0, 54.4, and 51.0%.Cows averaged 14 daily visits to the feeders with a range of 2 to 32. There were low correlations between concentrate allocation and number of feeder visits and concentrate allocation and total time spent in feeder.Returns over feeding system costs were $4.15, $4.03, and $3.71/cow per day for the three subherds.