Effects of forage presentation and addition of molasses-based liquid feed on dairy calf dietary selection and feed sorting of mixed diets

The objective of this study was to examine the effects of including a molasses-based liquid feed on sorting of a mixed diet of starter and hay, and to compare the nutrient composition of the ration consumed by calves offered hay and starter according to different feed presentations. Holstein bull and heifer calves were exposed for the first 8 wk of life to 1 of 3 feed presentation treatments: (1) starter and hay provided in separate buckets (n = 15), (2) a mixed diet of 80% starter and 20% hay (n = 16), or (3) a mixed diet containing the same ratio of starter and hay, with inclusion of 10% (as-is basis) liquid molasses (n = 14). Calves received 8 L/d of pasteurized waste milk and were weaned over a 10-d period beginning at 42 d of age. Intake was recorded daily and calves were weighed weekly. Fresh and refused feed were sampled on 3 consecutive days during wk 4 and 6 of the preweaning period and wk 8 immediately postweaning. Sorting was assessed through nutrient analysis of the feed samples, with additional sorting indices reflective of sorting for starter and hay components calculated based on weighted averages of individual nutrient intakes as a percent of predicated intakes. Dry matter intake and average daily gain did not differ among treatments. During the preweaning period, addition of molasses to the mixed diet did not affect the extent of feed sorting, with calves provided both mixed diets sorting, on average, in favor of starter and against hay. Postweaning, addition of molasses tended to reduce the extent of feed sorting, although calves on both treatments persisted in sorting for starter and against hay. Across treatments, there was an association between the pre- and postweaning extent of feed sorting, suggesting a degree of individual consistency in sorting behavior. Calves provided starter and hay separately consumed a diet consisting of approximately 18 to 19% hay preweaning and 14% hay postweaning, and generally had greater fiber intake and lower intake of nonfiber carbohydrates compared with calves provided a mixed diet. These results indicate that addition of molasses slightly reduced sorting during the postweaning period only. On average, calves provided both mixed diets sorted their feed in favor of starter and against hay, which mirrored dietary selection exhibited by calves offered hay and starter separately.     

Evaluating effects of providing hay on behavioral development and performance of group-housed dairy calves

Providing access to forage has been shown to influence feeding behavior and non-nutritive oral behavior in individually housed calves, and these effects may be enhanced or altered in calves reared in social housing. We evaluated the effect of hay provision on the behavioral development and performance of group-housed dairy calves. Holstein calves (n = 32) were group-housed (4 calves per group) at 17 ± 3 (mean ± SD) d of age. All calves were provided milk replacer (8 L/d) via an automated milk feeder and pelleted starter and water ad libitum. Pens were randomly assigned to receive either chopped coastal Bermuda grass in buckets adjacent to the starter trough (starter and hay, STH; n = 4 pens), or no additional feed (starter only, ST; n = 4 pens). Calves were weaned through a 10-d stepdown program beginning at 46 d of age. Intake of solid feed and hay were recorded daily, and body weights were measured weekly. The behavior of 2 focal calves per pen was recorded continuously from video for 12 h on 2 consecutive days during each of wk 4, 6, and 7 of life, to measure solid feed intake time, grooming, and pen-directed sucking. Hay provision influenced total feed intake, with calves provided hay having greater total solid feed intake in the week before weaning (0.79 vs. 0.55 kg/d, STH vs. ST, respectively; SE = 0.19). Average daily gain (ADG) was similar during the pre-weaning period but tended to be greater for STH calves during weaning. Calves in pens provided hay also had fewer unrewarded visits to the milk feeder during weaning (12.5 vs. 21.1 visits per 12 h, STH vs. ST, respectively; SE = 3.59) and performed less pen-directed sucking (9.11 vs. 19.3 min per 12 h, STH vs. ST, respectively; SE = 2.86). Self-grooming time and bout characteristics evolved differently between treatments over time, with pens of calves provided hay having a greater increase in frequency and duration of self-grooming bouts during weaning. Overall, we found that providing hay to pre-weaned calves resulted in behavioral and performance benefits, including greater total feed intake and reductions in pen-directed sucking, suggesting that access to hay may improve calf welfare.     

Effect of different forage sources on performance and feeding behavior of Holstein calves

One hundred seventy-nine Holstein male calves [44.7 kg of body weight (BW) and 8.3 d of age] participated in a series of 3 experiments to evaluate the effect of different forage sources on performance, apparent digestibility, and feeding behavior. Animals in each study were randomly assigned to 1 of 3 different dietary treatments: control (CON) calves were fed starter feed without any forage provision (this treatment was repeated in each of the 3 experiments), and the 2 other treatments consisted of the same starter feed plus a forage source: chopped alfalfa (AH) or rye-grass hay (RH) in the first study; chopped oat hay (OH) or chopped barley straw (BS) in the second study; corn silage (CS) or triticale silage (TS) in the third study. All calves were offered 2L of milk replacer (MR) at 12.5% dry matter (DM) twice daily via a bottle until 50 d of age, and 2L of MR at 12.5% DM during the week before weaning (57 d of age). The study finished when calves were 71 d old. Starter feed, MR, and forage intakes were recorded daily and BW weekly. Calves were individually housed and bedded with wood shavings. Compared with CON, animals receiving OH, TS, and BS consumed more starter feed (0.88 vs. 1.14, 1.17, 1.06 kg/d, respectively) and had greater average daily gain (0.72 vs. 0.93, 0.88, 0.88 kg/d, respectively). Animals in treatments RH, BS, CS, and TS consumed less forage (51 g/d) than AH (120 g/d) and OH (101 g/d) calves. Apparent organic matter, DM, and neutral detergent fiber digestibilities did not differ among treatments (81.5, 81.1, and 54.4%, respectively). Apparent crude protein digestibility was greater in RH, CS, and AH treatments than in CON (80.5 vs. 76.4%, respectively). Compared with CON calves, animals in the AH treatment spent less time eating starter feed and lying, animals in AH and RH treatments spent more time ruminating, with odds ratios (OR) of 5.24 and 5.40, respectively. The AH and RH calves devoted less time to performing nonnutritive oral behaviors (OR: 0.38 and 0.34, respectively), and TS calves tended to devote less time to perform nonnutritive oral behaviors (OR: 0.21) 1h after being offered MR and solid feed. In conclusion, free-choice provision of a forage source to young calves improves feed intake and performance without impairing digestibilities of DM, organic matter, crude protein, and neutral detergent fiber, and, depending on forage source, reduces nonnutritive oral behaviors and stimulates rumination.     

Growth performance,feeding behavior,and selected blood metabolites of Holstein dairy calves fed restricted amounts of milk: No interactions between sources of finely ground grain and forage provision

The objective of this study was to investigate the effects of grain sources and forage provision on growth performance, blood metabolites, and feeding behaviors of dairy calves. Sixty 3-d-old Holstein dairy calves (42.2 ± 2.5 kg of body weight) were used in a 2 × 3 factorial arrangement with the factors being grain sources (barley and corn) and forage provision (no forage, alfalfa hay, and corn silage). Individually housed calves were randomly assigned (n = 10 calves per treatment: 5 males and 5 females) to 6 treatments: (1) barley grain (BG) without forage supplement, (2) BG with alfalfa hay (AH) supplementation, (3) BG with corn silage (CS) supplementation, (4) corn grain (CG) without forage supplement, (5) CG with AH supplementation, and (6) CG with CS supplementation. All calves had ad libitum access to water and starter feed throughout the experiment. All calves were weaned on d 49 and remained in the study until d 63. Starter feed intake and average daily gain (ADG) was greater for calves fed barley than those fed corn during the preweaning and overall periods. Calves supplemented with CS had greater final body weight and postweaning as well as overall starter feed intake than AH and non-forage-supplemented calves. During the preweaning and overall periods, feeding of CS was found to increase ADG compared with feeding AH and nonforage diets. However, feed efficiency was not affected by dietary treatments. Calves supplemented with CS spent more time ruminating compared with AH and control groups; nonnutritive oral behaviors were the greatest in non-forage-supplemented calves. Regardless of the grain sources, the rumen pH value was greater for AH calves compared with CS and non-forage-supplemented calves. Blood concentration of BHB was greater for CS-supplemented calves compared with AH and non-forage-supplemented calves. Furthermore, body length and heart girth were greater for calves fed barley compared with those fed corn, and also in forage-supplemented calves compared with non-forage-supplemented calves. These results showed no interactions between grain sources and forage provision on calf performance; however, the inclusion of CS and barley in starter diets could enhance the growth performance of Holstein calves during the transition from liquid to solid feed.     

Effects of feeding different carbohydrate sources and amounts to young calves

Corn, oats, molasses, and soyhulls are commonly used carbohydrate sources in calf starters. A total of 180 calves were used in 4 studies to compare the use of these ingredients in calf starters. Study 1 compared textured starters with different amounts of molasses or sucrose. The control starter contained 5% molasses (A). The test starters contained greater concentrations of dietary sugar than starter A as either 10% molasses (B) or 5% molasses plus 1.5% granular sucrose (C). Starters B and C were equal in dietary sugar. Study 2 evaluated textured starters containing 0 or 25% whole oats for calves up to approximately 12 wk old. Study 3 evaluated pelleted starters containing 0 or 62.75% soyhulls for calves up to approximately 8 wk old. Study 4 evaluated textured starters containing 0, 14, 28, and 42% soyhulls for calves between approximately 8 and 12 wk old. Calves were housed in individual pens in an unheated nursery with curtain sides through 8 wk and then in group pens of 6 calves/pen from 8 to 12 wk. Calves were bedded with straw. In study 1, calves fed the starters with extra molasses or sucrose had an average of 9% slower average daily gain (ADG) and greater average fecal scores from 42 to 56 d and 9% slower ADG from 0 to 56 d than calves fed the textured starter with low molasses. In study 2, ADG and feed efficiency (kg of feed/kg of gain) were 22 and 20% less, respectively, in calves fed the starter without oats from 0 to 28 d, but there were no differences thereafter. In study 3, calves fed starters with soyhulls had a 10% slower ADG and 8% lower efficiency of gain from 28 to 56 d than calves fed the starters without soyhulls. In study 4, ADG declined linearly as soyhulls increased in the starter. The change in ADG was 14% from 0 to 42% soyhulls. Replacing corn in a starter with molasses, sucrose, or soyhulls reduced postweaning ADG and increased the cost of ADG. Whole oats were an acceptable substitute for corn.     

Effect of feed presentation on feeding patterns of dairy calves

The objectives of this study were to determine the effect of feed presentation on meal frequency and duration, as well as diurnal feeding patterns of dairy calves, and to assess any longer-term differences in feeding patterns resulting from previous experience. Twenty Holstein bull calves were exposed from wk 1 to 8 of life to 1 of 2 feed presentation treatments: concentrate and chopped grass hay (<2.5 cm) offered at a ratio of 7:3 as a mixture (MIX), or as separate components (COM). Feed was provided ad libitum. Calves received 8 L/d of milk replacer (1.2 kg of dry matter), with the amount progressively reduced after 5 wk to facilitate weaning by the end of wk 7. At the beginning of wk 9, all calves received the MIX diet and remained on trial for an additional 3 wk. Feeding behavior was recorded from video for 4 d during wk 6, 8, 9, and 11. In wk 6, calves fed MIX spent more time feeding than calves fed COM (56.7 vs. 46.8 min/d). In wk 8, calves fed MIX spent more time feeding (174.0 vs. 139.1 min/d) and had a lower rate of intake (11.5 vs. 14.7 g/min) compared with calves fed COM. Meal frequency was similar between treatments (12.2 meals/d). Diurnal feeding patterns in wk 8 were also affected by feed presentation, with calves fed MIX spending less time feeding at time of feed delivery and more time feeding throughout the rest of the daylight hours than calves fed COM. Diurnal feeding patterns of hay and concentrate in wk 8 differed for calves fed COM, with more time spent consuming hay at time of feed delivery and less time spent consuming hay throughout the rest of the day. Once calves previously fed COM were transitioned to the MIX diet in wk 9, meal frequency, meal duration, and diurnal feeding patterns were similar between treatments: both treatments spent similar amounts of time feeding (173.9 min/d) and had similar peaks in feeding activity at time of feed delivery, sunrise, and sunset. Provision of hay and concentrate to young calves as a mixed ration, compared with separate components, increases time spent feeding and results in more evenly distributed diurnal feeding patterns. However, differences in feeding patterns resulting from feed presentation did not persist after 8 wk of age, when all calves were fed a mixed ration.     

Interaction between the physical forms of starter and forage source on growth performance and blood metabolites of Holstein dairy calves

The objective of this study was to investigate the effects of the physical forms of starter and forage sources on feed intake, growth performance, rumen pH, and blood metabolites of dairy calves. Forty male Holstein calves (41.3 ± 3.5 kg of body weight) were used (n = 10 calves per treatment) in a 2 × 2 factorial arrangement of treatments with the factors being physical forms of starter (coarse mash and texturized) and forage source [alfalfa hay (AH) and wheat straw (WS)]. Individually housed calves were randomly assigned to 1 of the 4 dietary treatments, including (1) coarsely mashed (CM; coarse ground grains combined with a mash supplement) starter feed with AH (CM-AH), (2) coarsely mashed starter feed with WS (CM-WS), (3) texturized feed starter (TF; includes steam-flaked corn, steam-rolled barley combined with a pelleted supplement) with AH (TF-AH), and (4) TF with WS (TF-WS). Both starters had the same ingredients and nutrient compositions but differed in their physical forms. Calves were weaned on d 56 and remained in the study until d 70. All calves had free access to drinking water and the starter feeding at all times. No interaction was detected between the physical forms of starter feeds and forage source concerning starter intake, dry matter intake, metabolizable energy (ME) intake, average daily gain (ADG)/ME intake, ADG, and feed efficiency (FE). The preweaning and overall starter feed intake, dry matter intake, and ME intake were greater for calves fed TF starter diets than those fed CM starter diets. The ADG/ME intake was greater for calves fed TF starter diets than that fed CM starter. The FE was greater for calves fed TF starter diets compared with those fed CM starter during the preweaning, postweaning, and overall periods. The WS improved FE during the postweaning period compared with AH. The physical form of starter, forage source, and their interaction did not affect plasma glucose, triglycerides, and very low-density lipoprotein concentrations. Ruminal pH was greater for calves fed TF starter diets than those fed CM starter on d 30 of life. An interaction was observed between the physical forms of starter diets and forage source for β-hydroxybutyrate on d 28. These results showed that when starter diets contained similar ingredients and nutrient contents, processing calf starters to reduce the number of fine particles can improve the growth performance in dairy calves. Furthermore, the provision of WS improved FE and ADG of calves during the postweaning period.     

Effects of corn processing, particle size, and diet form on performance of calves in bedded pens

In a series of 5 trials, Holstein calves from zero to 12 wk old were housed in pens bedded with straw and fed diets to evaluate physical form of starters containing different processed corn on calf performance. Starters were formulated to have similar ingredient and nutrient compositions. Calves, initially less than 1 wk old, were housed in individual pens through 8 wk and weaned at 6 wk in trial 1 and at 4 wk in trials 2 and 3. In trials 4 and 5, calves initially 8 wk old were housed in group pens (6 calves/pen) from 8 to 12 wk. Trial 1 compared feeding calves a pelleted versus textured starter. Trial 2 compared feeding calves a textured starter versus feeding half meal starter with half textured starter. Trial 3 compared feeding calves textured starters containing whole, steam-flaked, or dry rolled corn. Trial 4 compared feeding calves textured starters containing steam-flaked versus dry rolled corn. Trial 5 compared feeding calves textured starters containing whole or dry rolled corn. Measurements included average daily gain (ADG), starter intake, feed efficiency, hip width change, body condition score change, fecal scores, and medical treatments. Physical form of starter feed did not affect any measurements in trials 1, 3, 4, and 5. In trial 2, calves fed starters manufactured with large amounts of fines had 11% less feed intake and 6% slower ADG than calves fed a textured starter. When starters contained similar ingredient and nutrient contents, manufacturing processes did not affect calf performance unless the diet contained a significant amount of fines, which reduced intake and ADG.     

Substituting corn silage with reconstituted forage or nonforage fiber sources in the starter feed diets of Holstein calves: Effects on intake,meal pattern,sorting, and health

We examined the effect of replacing corn silage (CS) with reconstituted alfalfa hay (RAH) or reconstituted beet pulp (RBP) in the starter diets on feeding behavior, sorting, and health criteria using 54 neonatal female Holstein calves that were assigned randomly to 3 groups receiving starter diets containing CS (10% on a dry matter basis), RAH, or RBP. The starter diets had the same nutrient composition and moisture level but differed in particle size distribution. Calves fed CS tended to have a lower intermeal interval compared with calves fed RAH before weaning; however, meal frequency and duration, eating rate, and meal size were not affected by treatment before and after weaning, which resulted in no changes in feed intake and time spent eating. Rumination frequency was higher for calves fed CS than for calves fed RAH or RBP after weaning. Feeding RBP decreased rumination duration compared with CS and RAH after weaning; however, calves fed RBP had a higher rumination bout interval compared with calves fed CS. Calves fed CS spent more time ruminating compared with calves fed RAH or RBP after weaning. Feeding CS tended to decrease and decreased time devoted to standing and lying, respectively, compared with calves fed RBP; however, calves fed RBP tended to spend more time on nonnutritive oral behaviors compared with calves fed RAH. Calves fed CS sorted against particles retained on the 8-mm sieve of the Penn State Particle Separator (PSPS) and for particles retained on the 1.18-mm sieve of the PSPS. Feeding RAH increased sorting for particles retained on the 8- and 1.18-mm sieves of the PSPS. Calves fed RBP sorted only for particles retained on the 1.18-mm sieve of the PSPS. Calves fed RBP tended to be more susceptible to developing pneumonia compared with calves fed CS or RAH; however, frequency and duration of diarrhea and pneumonia or number of days needed to medicate the diseases were unchanged across treatment groups. Initial (d 3) blood total protein concentration was similar (6.51 g/dL) across treatment groups. Overall, replacing CS with RAH or RBP did not affect time devoted to eating and feed intake due to no significant changes in meal size or intermeal interval before and after weaning. Calves showed feed sorting at the extent to which they balanced intake of nutrients and met their nutritional needs. Calves in general were healthy; therefore, CS, RAH, or RBP can be used interchangeably based on availability and competitive feed price.     

Competition during the milk-feeding stage influences the development of feeding behavior of pair-housed dairy calves

This study investigated how the feeding behavior of pair-housed calves develops in response to reduced teat and feed place availability. Twenty Holstein bull calves were pair housed and provided with milk replacer (MR) and grain concentrate ad libitum via either (1) 1 teat and feed bucket/pen, such that calves could not feed simultaneously [competitive feeding (CF)] or (2) 2 teats and feed buckets/pen [noncompetitive feeding (NCF)]. The calves were weaned during wk 7 of life by incrementally diluting the MR. Postweaning, all pens were managed identically and offered a complete pelleted diet ad libitum via 2 feed buckets/pen (NCF) in period 1 (wk 8 and 9) and period 3 (wk 12 and 13) and exposed to a competitive challenge with CF in period 2 (wk 10 and 11). Feeding times and competitive interactions were recorded from video for 3 d/wk in wk 2, 4, and 6 and 2 d/wk in wk 8 to 13. Meal criteria were used to calculate daily meal frequency, meal time, and synchronized meal time (the percentage of meal time when calves within the pen were engaged in simultaneous meals). Milk replacer intake was subject to a treatment × week interaction, with calves in CF pens having lower MR intake (wk 2: 8.3 vs. 10.0 L/calf per day for CF vs. NCF), but compensating by increasing intake to a greater extent over time (wk 4–5: 13.3 vs. 11.7 L/d for CF vs. NCF). Corresponding to MR intake, meal frequencies and feeding times evolved differently over this period, increasing in CF pens and decreasing in NCF pens (wk 2: 5.8 vs. 11.1 and wk 4–6: 6.2 vs. 5.1 meals/d for CF vs. NCF). Calves in CF pens also spent less time engaged in synchronized meals (28 vs. 51% of meal time; standard error = 7.1) and displaced each other 5 times more frequently during synchronized eating. Postweaning, calves in previously CF pens maintained 5 times greater displacement frequencies and had fewer overlapping meals than calves in previously NCF pens (34.5 vs. 40.7% of meals, respectively). Postweaning, when calves were all fed noncompetitively (2 buckets/pen in periods 1 and 3), calves previously fed CF had greater intakes in period 3 (4.87 vs. 4.44 kg/d) and a tendency for greater intake in period 1 (2.80 vs. 2.63 kg/d), greater rates of intake in period 3 (87.8 vs. 72.0 g/min) and a tendency for greater rates of intake in period 1 (44.3 vs. 38.9 g/min), and greater meal frequencies in both periods (11.1 vs. 9.9 meals/d). In the competitive challenge period (1 bucket/pen in period 2), intake, rates of intake, and meal frequencies were subject to treatment × week interactions: calves in NCF pens had lower intake and meal frequencies, but increased meal frequency, intake, and rate of intake over time to a greater extent than calves previously in CF pens. These results indicate that calves are able to adapt to moderate competition by increasing meal frequency and that behavioral responses to competition persist postweaning.     

Effects of fat inclusion in starter feeds for dairy calves by mixing increasing levels of a high-fat extruded pellet with a conventional highly fermentable pellet

The objective of this study was to evaluate the effect of inclusion of an extruded high-fat pellet mixed with a conventional pelleted calf starter on energy intake and performance around weaning in calves. To this end, 75 female Holstein newborn calves (41.0 ± 4.98 kg) were randomly assigned to 1 of 5 iso-nitrogenous solid feed treatments consisting of 4 levels of fat inclusion by mixing a low-fat highly fermentable control pellet with 3 different levels of inclusion of an extruded high-fat pellet [control (100:0), 90:10, 80:20, and 70:30], and a high-fat single pellet (HFSP). The HFSP was equivalent iso-energetic and iso-nitrogenous, although it had almost 1 percentage point difference in fat relative to the 80:20 treatment, to contrast the effect of the dual-component pellet mixture. The extruded high-fat starter feed contained a high proportion of fat (38%), mainly from hydrogenated palm fatty acids. Calves were offered a milk replacer up to 900 g/d, and then pre-weaned at 49 d of age by halving milk allowance until 56 d when calves were weaned. Calves had ad libitum access to the starter diets, chopped straw, and water. Individual milk replacer and starter intakes were recorded daily and BW was determined weekly. A glucose tolerance test was performed at 49 and 84 d of age to evaluate blood glucose homeostasis. Apparent total-tract digestibility was determined from 70 to 75 d of age. Calves on the 90:10 treatment had greatest starter feed intake mainly due to a marked increase in solid feed intake around weaning. Metabolizable energy intake was increased when the extruded pellet was included in the starter. No differences were present in digestibility of ether extract among solid feed treatments. The area under the curve of blood glucose concentration after the glucose tolerance test was greatest in 80:20; intermediate in 70:30, HFSP, and control; and lowest in 90:10 calves. No differences were observed for insulin or other parameters related to blood glucose homeostasis. Delivering dietary fat by mixing an extruded high-fat pellet with a conventional highly fermentable pellet to reach a total fat content of 7% results in increased starter intake, energy intake, and body weight gain until 84 d of age compared with a conventional low-fat pellet, or a single pellet with increased fat content.     

Reconstituted versus dry alfalfa hay in starter feed diets of Holstein dairy calves: Effects on feed intake,feeding and chewing behavior,feed preference,and health criteria

We investigated the effect of reconstitution of alfalfa hay on feeding and chewing behavior, sorting activity, and health status using 20 neonate Holstein male calves (3 d of age; 40.3 ± 1.30 kg of body weight) that were assigned randomly to 2 treatments, a starter feed containing either 10% dry (AH) or reconstituted alfalfa hay (RAH), each consisting of 10 calves. Alfalfa hay was reconstituted with water 24 h before feeding to achieve a theoretical dry mater (DM) content of 20%. Both starter diets had the same ingredients and nutrient compositions but differed in their DM content (90.9 vs. 66.6% DM for AH vs. RAH, respectively). Calves were weaned on d 50 and remained in the study until d 70. Reconstitution of alfalfa hay increased the percentage of particles retained on 8- and 1.18-mm sieves, but reduced feed materials retained on the bottom pan. Feeding RAH tended to increase meal frequency (preweaning) and increased meal duration (pre- and postweaning), and thereby increased time devoted to eating without affecting nutrient intake. Calves fed RAH tended to have lower eating rate during the pre- and postweaning periods. Tendencies to concurrent increase in rumination frequency and rumination duration in calves fed RAH increased time devoted to ruminating during the preweaning period; however, a tendency to longer rumination duration did not affect ruminating time during the postweaning period. Calves fed RAH spent less time resting and standing and more time drinking during the postweaning period. Non-nutritive oral behaviors were not affected by treatment during the pre- and postweaning period. Feeding RAH decreased sorting of particles retained on 8-mm sieve compared with AH; however, calves in both treatment groups sorted for particles retained on 8- and 1.18-mm sieves and against the feed materials retained on the bottom pan. Crude protein and neutral detergent fiber intakes of particles retained on the both 8- and 1.18-mm sieves increased in calves fed RAH versus AH, with no changes in intake of nutrients retained on the bottom pan. Calves fed AH were more susceptible to develop diarrhea (odds ratio = 2.02) and pneumonia (odds ratio = 4.74) and thereby had lower chances of being treated. We found no difference between treatment groups for frequency and medication days of diarrhea; however, calves fed RAH experienced fewer days with diarrhea. Furthermore, frequency and number of days with pneumonia and administration of medication were greater for calves fed AH compared with calves fed RAH. Blood concentrations of total protein and globulin tended to be higher in calves fed RAH compared with calves fed AH. Overall, feeding RAH increased time devoted to eating by increasing meal frequency and meal duration but did not affect feed intake due to lower eating rate. Calves in both treatment groups exhibited feed sorting at the extent to which they balanced intake of nutrients and met their nutritional needs. Calves, in general, were healthy, but it seems that feeding a diet containing reconstituted alfalfa hay has a potential health-promoting effect, possibly through reducing diet dustiness and improving immune status.     

Effects of forage provision to dairy calves on growth performance and rumen fermentation: A meta-analysis and meta-regression

A meta-analysis of the potential effect of forage provision on growth performance and rumen fermentation of dairy calves was conducted using published data from the literature (1998–2016). Meta-regression was used to evaluate the effects of different forage levels, forage sources, forage offering methods, physical forms of starter, and grain sources on the heterogeneity of the results. We considered 27 studies that reported the effects of forage provision to dairy calves. Estimated effect sizes of forage were calculated on starter feed intake, average daily gain (ADG), feed efficiency (FE), body weight (BW), and rumen fermentation parameters. Intake of starter feed, ADG, BW, ruminal pH, and rumen molar proportion of acetate increased when supplementing forage but FE decreased. Heterogeneity (the amount of variation among studies) was significant for intake of starter feed, ADG, FE, final BW, and rumen fermentation parameters. Improving overall starter feed intake was greater in calves offered alfalfa hay compared with those offered other types of forages. During the milk feeding and overall periods, improving ADG was greater for calves fed a high level of forage (>10% in dry matter) compared with those fed a low level of forage (≤10% in dry matter) diets. The advantages reported in weight gain at a high level of forage could be due to increased gut fill. Improving overall ADG was lower for calves offered forages with textured starter feed compared with ground starter feed. The meta-regression analysis revealed that changes associated with forage provision affect FE differently for various forage sources and forage offering methods during the milk-feeding period. Forage sources also modulated the effect of feeding forage on ruminal pH during the milk-feeding period. In conclusion, forage has the potential to affect starter feed intake and performance of dairy calves, but its effects depend on source, level, and method of forage feeding and physical form of starter feed independently of grain sources included in the starter feed.     

The effects of forage provision and group size on the behavior of calves

The effects of providing alternative forages to individual or group-reared calves on their behavior were examined in 2 experiments. In experiment 1, 24 calves were reared in groups of 3 or individually in straw-bedded pens from age 1 to 7 wk. One-half of the calves in each treatment were provided with ad libitum cut perennial ryegrass herbage. Grass intakes and time spent eating grass were greater for grouped calves than for individual calves. Providing grass reduced concentrate intake of grouped calves and reduced the time that all calves, but particularly individual calves, spent eating straw bedding. Ruminating time was increased by offering grass to grouped calves compared with individual calves. Grass reduced the frequency of calves licking their buckets and their pen, vocalizing, and investigating their pen. Particularly for grouped calves provision of grass reduced all grooming. Group rearing reduced the frequency of calves licking their bucket, vocalizing, and investigating their pen, but had no effect on the frequency of pen licking. Calves were weaned at wk 7 and transferred to indoor silage feeding or grazing. Most effects of group rearing and grass provision were not maintained after weaning, but calves that had received grass ate for longer periods when turned out to pasture. In experiment 2, 72 calves were offered a mixture of straw, molasses, and pot ale syrup or grass hay. Calves offered the straw mixture ate more forage and concentrates and grew faster than calves offered hay. It was concluded that nontraditional forages, such as fresh grass and straw mixtures, could benefit the behavior and growth of calves compared with hay and straw.     

Growth performance,feeding behavior,health status,and blood metabolites of environmentally heat-loaded Holstein dairy calves fed diets supplemented with chromium

We investigated the effect of Cr supplementation on growth performance, feeding behavior, health status, and blood metabolites of summer-exposed dairy calves during the pre- and postweaning periods. A total of 24 newborn Holstein female calves (1 d of age; 42.1 ± 0.89 kg of body weight) were assigned randomly to a control group (no Cr supplement; Cr?) or a Cr group (Cr+) receiving 0.05 mg of Cr/kg of body weight^0.75. During the study period, the average maximum temperature-humidity index was 81.3 units, indicating a high environmental heat load. Chromium was provided in colostrum and milk during the preweaning period, and in the starter feed during the postweaning period. Calves had free access to fresh water and starter feed throughout the experiment and were weaned on d 63. Starter feed intake and total dry matter intake were greater in Cr+ calves. Despite decreased meal frequency in Cr+ calves, during the preweaning period the starter feed intake increased due to increases in meal duration and meal size and a tendency for greater meal interval. Increased postweaning starter intake in Cr+ calves was attributed to a tendency for an increase in meal duration. Chromium-supplemented calves had greater overall weight gain, but their feed efficiency and rectal temperature were not affected by Cr treatment. Chromium supplementation tended to increase the heart girth during the preweaning and overall periods and increased the hip width during the postweaning and overall periods. Respiration rates were lower in Cr+ calves than Cr? calves during the preweaning and overall periods. During the preweaning period, the time spent in eating and ruminating per 12-h period was not affected by Cr treatment. During the postweaning period, the rumination time (min per 12-h period) was unaffected but total eating time (min per 12-h period) increased in Cr+ calves. Times spent resting, drinking, standing, lying, and in nonnutritive oral behaviors were not affected by treatments during the pre- and postweaning periods. Chromium supplementation had no effects on serum concentrations of cortisol, triiodothyronine, and thyroxine measured at weaning or the end of the trial. The Cr+ calves tended to have higher serum concentrations of glucose and a higher ratio of insulin to glucose measured at the end of the trial. In conclusion, Cr supplementation of both liquid and solid feeds improved growth performance in summer-exposed calves as a result of reduced respiration rate and increased feed intake; however, no beneficial effects were found on feed efficiency and insulin metabolism.     

The effect of milk-feeding method and hay provision on the development of feeding behavior and non-nutritive oral behavior of dairy calves

We investigated the interactive effects of common feeding management factors on the development of feeding and non-nutritive oral behaviors in preweaned calves through the weaning transition. Calves were randomly assigned to 1 of 3 treatments that differed by milk-feeding method (teat or bucket) and ad libitum access to chopped timothy hay: control, milk provided by bucket and no access to hay (CON; n = 10); milk provided by bucket and access to hay (H; n = 10); milk provided via a teat and access to hay (TH; n = 10). Calves had ad libitum access to concentrate and water, and were fed 6 L/d of pasteurized waste milk, divided into 2 meals. All calves were weaned by removing the second milk meal for 9 ± 2 d, beginning at 36 d of age. Daily concentrate and hay intake were recorded, and calves were weighed weekly to measure growth. We recorded the behavior of all calves using 2 s time-lapse video during time periods that encompassed milk meals, from 6000 h to 1000 h and 1600 h to 2000 h, on 2 consecutive focal days in wk 2 and 4. We continuously monitored lying time and activity using electronic data loggers. During the preweaning period, hay selection by H and TH calves was subject to a treatment × week interaction, with TH calves increasing hay intake to a greater extent over time. Similarly, we observed a tendency for a treatment × week interaction for hay dry matter intake. Before weaning, concentrate intake was subject to a treatment × week interaction, increasing to a greater extent over time for H and TH calves, but was greater overall for CON calves. As predicted, milk-feeding method and hay provision influenced the proportion of time devoted to feeding and non-nutritive behaviors. The CON calves spent the greatest amount of time performing non-nutritive sucking directed at the pen, TH calves the least, and H calves intermediate amounts. Considering the time TH calves sucked on their teat when milk was not present in addition to the time they spent sucking on pen fixtures, the total amount of time spent performing sucking behavior was similar between treatments. Although intake was similar across the weaning transition, CON calves had greater average daily gain than H calves, and TH calves were intermediate. Providing access to hay and milk via a teat during the milk-feeding stage decreased non-nutritive oral behaviors and influenced feeding behavior.     

The effect of palatability of protein source on dietary selection in dairy calves

Evidence has shown that soybean meal is perceived as more palatable than canola meal by dairy calves in short-term preference tests. This study evaluated the effect of protein source on longer-term dietary selection of dairy calves. In experiment 1, 40 Holstein bull calves (11.4 ± 4.3 d of age) were randomly assigned to 1 of 2 choice diets for 6 wk: base starter pellet (S; 12% crude protein; CP) and high-protein pellet (40% CP) containing either (1) soybean meal (SB) or (2) canola meal (CM). In wk 7 to 8, all calves were offered a single pelleted diet containing the protein source to which they were previously exposed. In experiment 2, 22 Holstein bull calves (9.9 ± 4.6 d of age) were offered, for 6 wk, a choice of 2 mixed pelleted diets: (1) 70% S and 30% SB (SB mix), or (2) 70% S and 30% CM (CM mix). In wk 7 to 8, calves were randomly assigned to 1 of 2 choice diets, as in experiment 1: (1) SB + S, or (2) CM + S. All feeds were provided ad libitum. Calves received 6 L/d of milk replacer [0.75 kg/d of dry matter (DM)] for the duration of both experiments. Feed intake was recorded daily and calves were weighed every 14 d. Feeds were sampled weekly to analyze DM and nutrient intake. Mixed diets in experiment 2 were analyzed for CP in wk 4 and 6 to assess feed sorting (calculated as actual CP intake as a percentage of predicted intake). In experiment 1, calves offered SB + S in wk 1 to 6 consumed more high-protein pellet than calves offered CM + S [73 vs. 42% of DM intake (DMI)] and, consequently, more CP (168 vs. 117 g/d). Solid feed DMI and average daily gain were similar between treatments. When offered a single diet in wk 7 to 8, calves offered starter containing soybean meal increased intake to a greater extent than calves offered the starter containing canola meal. In experiment 2, calves preferred the SB mix to CM mix (preference ratio: 0.7). Calves consumed more CP than predicted from SB mix in wk 4 and 6 (108 ± 2.0%), indicating that they were sorting in favor of SB. In contrast, calves consumed less CP than predicted from CM mix in wk 4 (81.48 ± 4.1%), indicating that they were sorting against CM. When assigned to choice treatments in wk 7 to 8 of experiment 2, calves offered SB + S consumed more protein pellet than calves offered CM + S (81 vs. 31% DMI) and consumed more CP (378 vs. 196 g/d). Average daily gain was greater for calves offered SB + S but DMI was similar. Overall, these results suggest that dietary selection was influenced by innate feed preferences, and milk-fed calves may not be sensitive to protein imbalances in their diet.     

Effects of feeding milk replacer at a moderate rate,ad libitum,or with a step-up program on Holstein calf growth performance to 4 months of age

The objective of this study was to evaluate 3 milk replacer (MR) feeding programs on calf performance to 4 mo of age. Male Holstein calves (n = 48; 2–3 d old) were randomly assigned to either a moderate rate of MR (MOD; 0.66 kg/d for 39 d, then 0.33 kg/d for 3 d), an ad libitum rate of MR (ADLIB; offered twice daily between 0630 and 0830 h and between 1430 and 1630 h for 35 d, 0.66 kg/d for 4 d, and 0.33 kg/d for 3 d), or a step-up rate of MR (STEPUP; increased from 0.32 to 0.62 kg/d in first 12 d, 0.66 kg/d for 27 d, and 0.33 kg/d for 3 d). The MR (25% CP, 18% fat) was fed twice daily to d 39 and once daily thereafter. During the nursery phase (0–56 d), calves were housed in individual pens and offered textured starter (40% starch, 21% CP on a DM basis) and water ad libitum. Calf body weight (BW) was measured initially and weekly thereafter. Hip widths (HW) were measured initially and every 2 wk thereafter. In the grower phase, (57–112 d), calves were grouped by previous treatment and moved to group pens (4 calves/pen). The same starter used in the nursery phase was blended with 5% chopped grass hay and offered ad libitum. Calf BW and HW were measured on d 56, 84, and 112. Total MR intake per calf averaged 27, 51, and 25 kg for MOD, ADLIB, and STEPUP programs, respectively, with a range of 42 to 63 kg for ADLIB. In the nursery phase, starter intake and feed efficiency were less for ADLIB versus MOD, whereas fecal scores and abnormal fecal score days were greater for calves fed ADLIB versus MOD. Calves fed STEPUP had lesser average daily gain than calves fed MOD. During the grower phase, initial BW was greater for ADLIB versus MOD, though final BW was not different between MOD and ADLIB or STEPUP. Calves previously fed MOD had greater average daily gain, feed efficiency, and HW change than calves fed ADLIB. In this study, feed efficiency was lower when MR was fed ad libitum, and growth advantages observed at 2 mo were lost by 4 mo of age.     

Milk- and starter-feeding strategies to reduce cross sucking in pair-housed calves in outdoor hutches

Social housing of preweaned calves can benefit their welfare, but housing and cross sucking are potential barriers to adoption for farmers. For farms using outdoor hutches, an option is to pair adjacent hutches with a shared fence. Our objective was to investigate milk- or starter-feeding strategies to mitigate cross sucking in this system. Holstein heifers were housed in pairs (n = 32 pairs) and divided into 4 treatments (n = 8 pairs each) in a 2 × 2 factorial design: milk in an open bucket with starter in only a bucket (OB-SB), milk in an open bucket and starter in both a bucket and a specialized teat bottle (Braden bottle; OB-BB), milk in a slow-flow teat bucket with starter in only a bucket (TB-SB), or milk in a slow-flow teat bucket and starter in both a bucket and a specialized teat bottle (TB-BB). When starter was first offered (d 6 ± 1 of life, mean ± SD), calf latency to approach was recorded, averaged within pairs, and compared between starter treatments using a linear mixed model with fixed effect of treatment and random effect of pair within treatment. Calves were initially bottle fed; milk treatments began on d 14 ± 1 of life and ended when calves were completely weaned (d 53 ± 1). Calves were observed for behaviors such as drinking milk and cross sucking twice weekly for 30 min during the afternoon milk meal using continuous video, with values averaged within pairs. Linear mixed models were run separately before (wk 3–6) and after (wk 7–8) weaning, with fixed effects of milk- and starter-feeding treatments, week, and the 2- and 3-way interactions, with week as repeated measure and pair as subject. Pairs with Braden bottles and buckets approached starter sooner than those with only buckets (Braden bottles vs. no Braden bottles: 13.1 ± 6.1 vs. 33.2 ± 6.1 min, LSM ± SEM). Before weaning, pairs with open buckets for both milk and starter cross sucked for at least twice as long (OB-SB: 2.9 ± 0.3 min) as all other treatments (OB-BB: 1.5 ± 0.3 min; TB-SB: 0.4 ± 0.3 min; TB-BB: 0.5 ± 0.3 min). This pattern held during weaning, when cross sucking increased overall (OB-SB: 3.9 ± 0.4 min; OB-BB: 1.8 ± 0.4 min; TB-SB: 0.9 ± 0.4 min; TB-BB: 1.6 ± 0.4 min). Regardless of starter treatment, calves spent less time cross sucking when fed milk in teat buckets, which extended the milk meal relative to open buckets (teat bucket vs. open bucket: preweaning = 7.0 ± 0.2 vs. 1.6 ± 0.2 min; weaning = 3.0 ± 0.1 vs. 0.6 ± 0.1 min). When calves are fed milk in open buckets, a novel option for reducing cross sucking is to provide starter through a specialized bottle. Nonetheless, providing milk in slow-flow teat buckets had the greatest effect on reducing cross sucking by directing suckling to the teat instead of another calf or pen objects.     

Hay intake improves performance and rumen development of calves fed higher quantities of milk

Research to date has suggested that access to forage before weaning can limit rumen development in calves, but no research has yet addressed the role of forage for calves fed higher quantities of milk. This study compared performance and rumen development of calves provided high volumes (equivalent to approximately 20% of calf birth weight) of milk with and without access to hay. At d 3 of age, individually housed calves were randomly assigned to treatment (either ad libitum access to chopped grass hay or no forage; n = 15 calves per treatment, 10 heifers, and 5 bulls). All calves were provided ad libitum access to water and starter throughout the study. All calves were offered 8 L of milk/d from a nipple bottle from d 3 to 35, 4 L/d from d 36 to 53, and 2 L/d until weaning at d 56. Solid feed intake and growth parameters were monitored from d 3 to 70. At d 70, males from both treatments were slaughtered to measure rumen development parameters. Overall dry matter (DM) intake from solid feed did not differ between treatments before wk 5. However, during wk 6 to 10, calves fed forage consumed more total DM (starter plus hay) than did calves fed no forage. Hip and wither height, heart girth, and body barrel at d 3, 56, and 70 did not differ between treatments. Reticulorumen weight was heavier in calves fed hay versus those fed only starter (12.77 ± 1.29 vs. 7.99 ± 0.69 kg with digesta; 1.89 ± 0.05 vs.1.60 ± 0.09 kg without digesta). Body weight without digesta was similar in calves fed forage or no forage. Mean rumen pH was higher in calves fed hay compared with those fed no forage (5.49 ± 0.08 vs. 5.06 ± 0.04). In conclusion, provision of chopped hay to calves fed high volumes of milk can promote solid feed DM intake and rumen development without affecting BW gain.