A method of outdoor housing dairy calves in pairs using individual calf hutches

Interest in housing dairy calves in groups is currently growing. Group housing using individual calf hutches, a resource already available in most dairy farms in North America, could provide a novel housing method that can be a simple way to implement group housing on farm. The main objective of this study was to determine whether pair housing dairy calves in hutches outdoors would result in similar weight gain and milk intake compared with individual housing in hutches. The study was designed to avoid competition for resources (including milk and solid feed, teat, bucket, outdoor space, and hutch) to test a setup that has the potential to maximize performance and calf growth. Secondary objectives were to document how calves in both treatments use their environment in terms of time spent and behaviors performed in each area, how paired calves interact, and the time they spend together. Single calves (n = 6/season) were housed in 1 hutch with an attached outdoor environment; paired calves (n = 6 pairs/season) were given twice the resources. Calves were fed up to 16 L/d of milk replacer. Daily milk intake and weekly weight gains were recorded. Behavioral observations were recorded live once per week for 5 (summer) or 4 (winter) nonconsecutive periods. Paired and single calves had similar weight gain (averaging from 1.1 to 1.3 kg/d across trials) and milk intake (averaging from 11.1 to 13.7 kg/d across trials), showing no difference in performance between treatments. Low occurrences of cross sucking (averaging from 0.1 to 0.4 bouts/h of observation per pen across trials) and displacements at the teat (0.8 to 1.4 bouts/h of observation per pen across trials) were found. All calves altered their behavior in some way to accommodate companions; paired calves were seen interacting and spending time together (i.e., lying in the same hutch), and in the summer trial single calves spent less time lying inside the hutch than paired calves, presumably to have visual access to other calves. The solution of mixed indoor and outdoor housing environments tested as part of this study showed that calves make use of all spaces provided to them in winter and in summer conditions while maintaining good performance. Housing calves in pairs using individual hutches can be a suitable alternative to housing calves individually in hutches outdoors.     

Effects of pair versus single housing on performance and behavior of dairy calves before and after weaning from milk

This experiment tested the effects of pair versus single housing on the performance and behavior of dairy calves before and after weaning. Twenty-seven Holstein calves were separated from the dam within 6 h of birth, housed in individual pens for 4 d, and then assigned to either continued individual housing (n = 9 calves) or pair housing (n = 9 pairs). Calves had ad libitum access to starter, hay, and water via buckets. Pasteurized whole milk was fed via teat twice a day for 2 h at ad libitum volumes until d 36. During the milk-feeding period, paired calves showed higher intakes of starter than did the individually housed calves (averaging 93 vs. 59 ± 11 g/d per calf). Calves were weaned from milk from d 37 to 41 by progressive dilution of milk with water, and the teat was removed on d 49. Calves in both treatments vocalized in response to teat removal but this response was less in paired calves than in individually housed calves (84 vs. 194 ± 12 calls/2-h period per calf on d 49). On d 56, calves were moved to group pens, mixed with other calves, and observed for 15 d. Starter, water, and hay were available ad libitum via automatic feeders. Compared with calves previously housed in single pens, paired calves had a shorter latency to start feeding (9.1 ± 2.6 vs. 49.5 ± 4.1 h/calf), visited the starter feeder more frequently (41.6 ± 3.0 vs. 26.4 ± 3.3 visits/d per calf), spent more time at the feeder (87.8 ± 2.5 vs. 65.3 ± 2.9 min/d per calf), and consumed more starter (3.4 vs. 2.3 ± 0.2 kg/d per calf). Weight gains at mixing were higher for paired than for individually housed calves on d 2 and 3 after mixing (0.5 vs. −2.4 ± 0.3 kg/d per calf; and 0.8 vs. −0.9 ± 0.3 kg/d per calf, respectively). The results indicate that pair housing during the milk-feeding stage reduces calf responses to weaning and improves performance after weaning when calves are housed in groups.     

Effects of pair versus individual housing on the behavior and performance of dairy calves

This study compared the health, performance, and behavior of individually and pair-housed calves fed milk ad libitum by artificial teats. Calves were separated from their dams within 24 h of birth and assigned to housing in either a single pen (10 calves) or a group pen (10 pairs of pair-housed calves). Calves were gradually weaned at approximately 5 wk of age and remained on the experiment until wk 8. Behavior was video recorded during wk 2 to 8. Before and after weaning, calves gained weight steadily with no differences between treatments. During the week of weaning, pair-housed calves continued to gain weight normally, but the individually housed calves experienced a growth check. There were no differences between groups in the amounts of milk, starter, or hay consumed, or in the incidence of scouring. There were also no differences in the amount of time spent self-grooming, sucking on the teat, or lying down. However, pair-housed calves spent more time standing inactive, more time moving, and less time with their head out of the pen than individually housed animals. Paired calves spent approximately 2% of the day in social contact, and the incidences of agonistic behavior and cross-sucking were very low. These results indicate that housing dairy calves in pairs allows benefits such as increased space for movement and social opportunities with no disadvantages in health and weight gains.     

The effect of rearing substrate and space allowance on the behavior and physiology of dairy calves

The objective of this study was to investigate the effect of rearing substrate and space allowance on the behavior and physiology of dairy calves. At 1 wk of age, 72 calves were moved into 1 of 18 experimental pens (n = 4 calves/pen) where they remained until 6 wk of age. Half of the pens had floors covered with quarry stones (QS) and the other half were covered with sawdust (SW). For each substrate type, calves were reared at 1 of 3 space allowances: 1.0, 1.5, or 2.0 m²/calf. Behavior was video-recorded continuously for 24 h in the home pen at 2, 4, and 6 wk of age; the time calves spent lying, standing, walking, and running were estimated using 1-min instantaneous scan sampling. Body weight, cleanliness, fecal fluidity, and skin surface temperature were recorded at 1, 4, and 6 wk of age. Escherichia coli numbers were assessed on the skin surface of the shoulder and in feces of calves at 4 and 6 wk of age. Blood samples were taken at 1, 4, and 6 wk of age to measure cortisol, creatine kinase, immunoglobulin G, serum amyloid A, and total protein concentrations. Calves reared on QS spent less time lying and walking and more time standing at 4 and 6 wk of age compared with calves reared on SW. Furthermore, calves reared at a space allowance of 2.0 m²/calf spent less time lying and more time standing and walking compared with calves reared at a space allowance of 1.0 and 1.5 m²/calf. Calves reared on QS had lower skin surface temperatures compared with calves reared on SW. Fecal fluidity scores were lower in calves reared on QS than SW at 2 wk of age. Fewer E. coli were recovered from the shoulder of calves reared on QS than those of calves reared on SW, but fecal E. coli counts were similar between rearing substrates and space allowances. Serum amyloid A concentrations were lower in calves reared on QS than SW. We detected no effect of rearing substrate or space allowance on body weight, cleanliness, or concentrations of cortisol, creatine kinase, immunoglobulin G, and total protein. In conclusion, lower skin temperature in combination with reduced lying behavior may reflect reduced comfort of calves reared on QS. Furthermore, a space allowance of 2.0 m²/calf may provide calves with more opportunity to perform active behaviors.     

Health,physiology, and behavior of dairy calves reared on 4 different substrates

The objective of this study was to compare the health, physiology, and behavior of group-housed calves reared on wood shavings with those reared on alternative surfaces. At 1 wk of age, 80 calves were moved into 1 of 20 experimental pens (n = 4 calves/pen) where they remained until 6 wk of age. Pens had floors covered with pea gravel (PG), rubber chip (RC), sand (SA), or wood shavings (WS; n = 5 pens/substrate). Body weight, cleanliness, health, and skin surface and vaginal temperature were recorded at 1, 3, and 6 wk of age. Escherichia coli numbers were assessed on the skin surface of the shoulder and in the feces of calves at 3 and 6 wk of age. Blood samples were taken at 1, 3, and 6 wk of age to measure hematological values and cortisol, IgG, and lactate concentrations. Behaviors (lying, running, and self-grooming) were recorded in the home pen at 1, 3, and 6 wk of age using video recorders and accelerometer data loggers. At 6 wk of age, calves were tested individually in an arena test and behavior was recorded continuously for 20 min. Body weight did not differ among calves reared on PG, RC, SA, or WS, regardless of age. All calves were clean and no calves displayed any signs of lameness, leg lesions, or injuries at wk 1, 3, or 6, regardless of substrate. The number of E. coli recovered from a surface area of 100 cm² on the shoulder of each calf was affected by rearing substrate, with more E. coli recovered from calves reared on WS than PG, RC, or SA at 3 and 6 wk of age. Fecal E. coli counts were not affected by rearing substrate at 3 or 6 wk of age. Over the entire study period, calves reared on PG and SA had lower skin temperatures than calves reared on RC or WS, but skin temperature was similar between calves reared on PG and SA. However, vaginal temperature did not differ among calves reared on different substrates at 1, 3, or 6 wk of age. Hematology values and cortisol, IgG, and lactate concentrations of calves were similar among rearing substrates over the 6-wk study period. In the home pen, rearing substrate did not influence time spent lying; however, calves reared on WS performed more lying bouts than calves reared on PG or SA. In addition, rearing substrate did not influence the time calves spent running; however, calves reared on WS spent more time self-grooming than calves reared on PG, RC, and SA. During a 20-min arena test, running, bucks, jumps, and kicks performed by calves was not affected by rearing substrate. In conclusion, the physiology and behavior of calves reared on PG, RC, and SA was similar to WS, which is considered the preferred rearing substrate to use when rearing calves. Therefore, PG, RC, and SA may be acceptable substrate options when rearing group-housed dairy calves.     

The effect of group composition and age on social behavior and competition in groups of weaned dairy calves

The objective of the present study was to investigate how group composition affects behavior and weight gain of newly weaned dairy calves and how age within heterogeneous groups affects behavior and competition. Seventy-two calves were introduced into 6 groups of 12 calves, of which 3 groups were homogeneous and 3 groups were heterogeneous (including 6 young and 6 old calves). The 9.8 m × 9.5 m large experimental pen had 4 separate lying areas as well as a feeding area. Behavior and subgrouping were recorded on d 1, 7, and 14 after grouping, and calves were weighed before and after the experimental period of 14 d. Analysis of the effect of group composition on behavior and weight gain included young calves in heterogeneous groups and calves in homogeneous groups within the same age range at grouping (30 to 42 d). Irrespective of group composition, time spent feeding and lying increased, whereas time spent active decreased from d 1 to 7. In homogeneous groups, calves were more explorative on d 1 after grouping. Finally, calves in homogeneous groups had a higher average daily weight gain than calves in heterogeneous groups. Analysis of the effect of age included young and old calves of heterogeneous groups. Young calves were less explorative than old calves. Young calves were more active than old calves on d 1 but less active on d 7. Time spent lying and lying alone increased over time. More displacements from the feed manger were performed by old calves than by young calves. An analysis including all calves in both homogeneous and heterogeneous groups showed that when lying, calves were evenly distributed on the 4 lying areas and formed subgroups of on average 3 calves. In conclusion, age heterogeneity leads to increased competition, which may have a negative influence on the young calves’ performance.     

Relationships between starch concentration of dry feed,diet digestibility,and growth of dairy calves up to 16 weeks of age

Our objective was to examine the potential relationship between starch concentration of dry feed and growth performance of young dairy calves via mixed-effects model analyses. A database was developed from 6 published studies conducted at the Nurture Research Center, Provimi (Brookville, OH), from 2008 to 2017 that included 18 dietary treatments and 372 calves at 0 to 8 wk of age in 5 nursery trials and 26 dietary treatments and 660 calves at 8 to 16 wk of age in 8 grower trials. The dry feeds ranged from 10.1 to 53.3% starch, 12.1 to 45.3% neutral detergent fiber, and 2.7 to 3.0 Mcal/kg of metabolizable energy [dry matter (DM) basis]. In all nursery trials, with increasing starch concentration in starter, average daily gain (ADG), hip width change, and starter intake linearly increased. In all grower trials, as starch concentration of dry feed increased, ADG, hip width change, and ADG/DM intake linearly increased; DM intake and DM intake/body weight were unaffected. In addition, the calves at 6 to 16 wk of age had greater digestibility of DM and crude protein with increasing starch concentration of dry feed. As indicated by meta-regression analysis, growth responses to starch concentration were influenced by metabolizable energy concentration in dry feed fed to the calves up to 16 wk of age. Changing starch from 23 to 43% on a DM basis (a typical range in the US industry) was predicted to increase ADG and hip width change by 5.8 and 5.0%, respectively, for calves at 0 to 8 wk of age and by 9.6 and 11.2%, respectively, for calves at 8 to 16 wk of age. Positive linear relationships between starch concentration of dry feed with DM digestibility, ADG, and hip width change reflect the importance of starch in the diets of young dairy calves.     

Short communication: The effect of diarrhea and navel inflammation on the lying behavior of veal calves

Many veal calves arrive to growing facilities with diseases, including diarrhea and navel inflammation. Observing neonatal calf behavior, such as lying behavior, can be used to better detect and determine the implications of these diseases. The aim of this study was to determine the effect of navel inflammation and diarrhea on lying behavior in neonatal veal calves. This study was part of a larger experiment that included a total of 360 male Holstein calves from 3 cohorts; from these calves, we selected a subset of 125 calves (every third calf as they entered the barn) to be fitted with 3-dimensional accelerometers (Hobo Pendant G data loggers; Onset Computer Corp., Bourne, MA) on 1 hind leg to continuously measure lying time, number of lying bouts, and lying bout duration. Calves were housed individually on slatted flooring (Tenderfoot; Tandem Products Inc., Minneapolis, MN) in 3 rooms of a mechanically ventilated barn. Health exams were conducted twice weekly for 2 wk starting the day after arrival. Exams included rectal temperature, navel score (0 = normal, 1 = mildly inflamed, 2 = moderately inflamed, 3 = severely inflamed), and fecal score (0 = normal, 1 = semiformed, 2 = loose, 3 = watery). Calves were considered to have navel inflammation (n = 22) or diarrhea (n = 15) if they scored ≥2 during at least 3 of the 4 health exams. The lying behavior of these calves was compared with that of normal calves (n = 18) that had no signs of illness and rectal temperatures <39.4°C during at least 3 of the 4 health exams. Data were analyzed using a repeated-measures ANOVA; models included cohort (1, 2, or 3), health status (normal, navel inflammation, or diarrhea), week (1 or 2), and a health by week interaction. There was an effect of health status on lying time, whereby normal calves spent more time lying compared with calves with inflamed navels and tended to spend more time lying compared with calves with diarrhea. There was no effect of health status on the number of lying bouts per day or on the duration of lying bouts. There were no health by week interactions. Results indicate that neonatal veal calves with navel inflammation and diarrhea may be less comfortable than calves without these conditions. Veal producers should consider adapting their facilities to create more comfortable lying environments to help calves better recover from disease, such as by adding a hospital pen with comfortable bedding.     

The effect of neomycin inclusion in milk replacer on the health,growth, and performance of male Holstein calves during preweaning

The prophylactic use of oral antimicrobials, such as neomycin, in milk replacer (MR) or whole milk is a common practice in calf-rearing that is thought to aid in preventing disease. Heavy reliance on antimicrobials is of concern not only because of the development of antimicrobial resistance, but also because of the potentially negative effects on health. The objective of this study was to investigate the effects of neomycin on calf health and growth performance. One hundred and sixty calves (approximately 3–10 d of age), distributed across 2 experimental periods, were stratified by body weight (BW) and serum total protein, and assigned to 1 of 3 treatments: control (CON; nonmedicated MR, n = 60), short-term antibiotic (ST; neomycin mixed in MR from d 1–14, n = 50), or long-term antibiotic (LT; neomycin in ?MR from d 1–28, n = 50). Arrival BW (47.69 ± 0.87 kg) and serum total protein (5.67 ± 0.09 g/dL) were not different between treatment groups. Neomycin in ST and LT was dosed in MR at a rate of 20 mg/kg of BW and was adjusted weekly according to BW. Calf BW was measured weekly for 49 d, and health indicators (fecal score, attitude score, respiratory score, and rectal temperature), MR intake, starter intake, and the use of additional electrolytes and antimicrobials were recorded daily. Calves in the CON group experienced a higher proportion of days with diarrhea (20.32 ± 0.02%) compared with ST (14.70 ± 0.02%) or LT (13.80 ± 0.02%) calves, as well as longer bouts of diarrhea (7.45 ± 0.38 d, 5.69 ± 0.46 d, and 5.62 ± 0.45 d for CON, ST, and LT calves, respectively). Calves in the CON group also experienced higher fecal scores (score of 0.64 ± 0.04) than ST (score of 0.53 ± 0.04) or LT (score of 0.49 ± 0.04) calves, especially at d 7. However, no differences were observed in other health-related measures. The time to reach first diarrhea and first respiratory illness was not different between treatments, nor was the time to recover from respiratory illness. The time to intervention with additional electrolytes or antimicrobials was not different between treatment groups. Furthermore, growth performance, feed intake, and feed conversion ratio were not different. No differences were found when comparing ST and LT, except in the defined daily dose of total antimicrobials received. Calves in the LT group received a higher overall dose than ST calves, and both ST and LT calves received a higher dose than CON calves, which received no prophylactic antimicrobials. Given that there were no differences in performance variables and no additional health benefits aside from reduced fecal scores in calves fed neomycin, current practices involving the use of antimicrobials on dairy and veal operations need to be considered more prudently.     

Characterizing social behavior,activity, and associations between cognition and behavior upon social grouping of weaned dairy calves

Weaned dairy calves are commonly exposed to changing physical and social environments, and ability to adapt to novel management is likely to have performance and welfare implications. We characterized how behavioral responses of weaned heifer calves develop over time after introduction to a social group. Previously individually reared Holstein heifer calves (n = 15; 60 ± 5 d of age; mean ± standard deviation) were introduced in weekly cohorts (5 ± 3 new calves/wk) to an existing group on pasture (8 ± 2 calves/group). We measured activity and behavior on the day of initial introduction and after 1 wk, when calves were exposed to regrouping (addition of younger calves and removal of older calves from the pen). Upon introduction, calves had 2 to 3 times more visits to each region of the pasture; they also spent more time at the back of the pasture, closest to where they were introduced and furthest from the feeding area (25.13 vs. 9.63% of observation period, standard error = 5.04), compared with behavior after 1 wk. Calves also spent less time feeding (5.0 vs. 9.6% of observation period, standard error = 0.82) and self-grooming (0.52 vs. 1.31% of observation period; standard error = 0.20) and more time within 1 to 3 body lengths of another calf (16.3 vs. 11.9% of observation period, standard error = 2.3) when initially grouped. We also explored whether behavioral responses to initial postweaning grouping might be associated with individual differences in behavioral flexibility. To evaluate this, we assessed cognition of individually housed calves (n = 18) at 5 wk of age using a spatial discrimination task conducted in a T-maze to measure initial learning (ability to learn the location of a milk reward) and reversal learning (ability to relearn location of the milk reward when it was switched to opposite arm of the maze). Calves were categorized by reversal learning success (passed, n = 6, or failed, n = 8). Calves that passed the reversal learning stage of the cognitive task spent less time at the back of the pen (9.3 vs. 27.4% of observation period, standard error = 5.5) and tended to have lower latency to feed (121.8 vs. 306.2 min; standard error = 96.4) on the day of introduction compared with calves that failed reversal learning. Overall, we found that initial introduction to social grouping had a marked influence on behavior of weaned calves that decreased over time. Further, these results suggest that individual variability in cognitive ability may be predictive of behavioral responses and ability to adapt to a novel environment.     

Social housing influences the behavior and feed intake of dairy calves during weaning

We investigated the effect of social housing on the behavioral, intake, and physiological changes that occur at weaning for dairy calves fed milk ad libitum. These changes were evaluated during the weaning (d 40 to 48 of age) and postweaning (d 49 to 56 of age) stages. Twenty male Holstein calves were fed milk replacer ad libitum and weaned gradually by dilution over 9 d starting at d 40 of age. Calves were housed in pairs (10 calves) or individually (10 calves) from birth until the beginning of the postweaning phase, when all calves were paired. Feed and water intake were monitored daily. Feeding time was video-recorded, and blood β-hydroxybutyrate concentration was measured on alternate days beginning on d 40 and ending on d 56 of age. Electronic accelerometers continuously recorded standing and lying behavior for the 17-d study. Solid feed consumption increased by more than 5-fold over the weaning phase in all calves; during this phase pair-housed calves consumed more than twice (0.96 vs. 0.50 kg/d on d 48) that of the individually housed calves. Postweaning all calves rapidly increased their solid feed intake, and to a greater extent for previously individually housed calves, such that intake was similar between treatments by d 56. Free water intake was stable during weaning; however, a decrease (of 6.6 L) occurred in the constituent milk replacer water intake across this phase. As result, total water intake (free water + milk replacer water content) decreased (by 6.0 L) over the weaning phase between d 40 (14.9 L/d) and d 48 (8.9 L/d). On the first day postweaning (d 49), total water intake for all calves increased sharply (to 19.0 L/d) and then returned to a lower baseline (13.2 L/d) the next day (d 50), and slowly increased over the following week. During the weaning phase, feeding time and feeding rate increased with time for all calves, whereas pair-housed calves had greater feeding rates than individually housed calves (13.4 vs. 6.6 g of DM/min). After weaning, calves previously housed individually spent more time feeding in the early hours of the day than calves housed in pairs. Lying time and lying bout frequency decreased with calf age during the weaning period across treatments, and pair-housed calves tended to spend less time lying than individually housed calves (1,015 vs. 1,039 min/d) during this time period. Blood β-hydroxybutyrate increased across treatments over the weaning period, with the largest increase occurring between d 48 (0.05 mmol/L) and d 50 (0.2 mmol/L). These results show that calves alter their behavioral patterns during weaning and that housing calves in pairs may ease the transition from milk to solid feed.     

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 colostrum storage conditions on dairy heifer calf serum immunoglobulin G concentration and preweaning health and growth rate

The objective of the present study was to compare serum IgG concentration, weight gain, and health characteristics in Irish spring-born dairy calves fed colostrum stored using a range of conditions. Immediately after birth, 75 dairy heifer calves were assigned to 1 of 5 experimental colostrum treatments: (1) fresh pasteurized colostrum, fed immediately after pasteurization; (2) fresh colostrum, fed immediately after collection but not pasteurized; (3) colostrum stored unpasteurized at 4°C in a temperature-controlled unit for 2 d before being fed to calves; (4) colostrum stored unpasteurized at 13°C in a temperature-controlled unit for 2 d before being fed to calves; and (5) colostrum stored unpasteurized at 22°C in a temperature-controlled unit for 2 d before being fed to calves. All colostrum had IgG concentrations >50 g/L and was fed to calves promptly after birth. Blood samples were obtained from calves via the jugular vein at 0 h (before colostrum feeding) and at 24 h of age to determine the rate of passive transfer of IgG; individual calf live-weights were recorded to monitor weight gain (kg/d) from birth to weaning. Colostrum stored in warmer conditions (i.e., 22°C) had >42 times more bacteria present and a pH that was 0.85 units lower and resulted in a serum IgG concentration that was almost 2 times lower compared with colostrum that was pasteurized, untreated, or stored at 4°C for 2 d. Colostrum stored at 4°C for 2 d had more bacteria present than pasteurized and fresh colostrum but did not result in reduced calf serum IgG concentrations. Average daily weight gain from birth to weaning did not differ among treatments. Even if colostrum has sufficient IgG (>50 g/L) but cannot be fed to calves when freshly collected, storage at ≤4°C for 2 d is advisable to ensure adequate passive transfer when it is consumed by the calf.     

The effect of Cryptosporidium parvum,rotavirus, and coronavirus infection on the health and performance of male dairy calves

The objective of this prospective cohort study was to investigate the effect of bovine coronavirus (BCoV), bovine rotavirus (BRoV), and Cryptosporidium parvum on dairy calf health and performance and to determine the prevalence of these pathogens. A total of 198 male dairy calves housed at a grain-fed veal facility were examined from June 11, 2018, to October 9, 2018. Calves were fed milk replacer twice daily and housed individually until weaning at 56 d. Once weaned, calves were moved into groups of 5 until they were moved to a finishing facility at 77 d. At the grain-fed veal facility, calves were scored for fecal consistency for the first 28 d and had fecal samples taken on arrival and at 7 and 14 d. Fecal samples were frozen and submitted to a commercial laboratory, where they were tested for BCoV, C. parvum, and 2 groups of BRoV: group A (BRoV A) and group B (BRoV B). Calves were weighed on arrival and at 14, 49, 56, and 77 d using a digital body scale. Treatments for disease and mortalities that occurred over the 77 d were also recorded. Statistical models, including Cox proportional hazards and repeated measures models, were built to determine the effect of infection with 1 of the pathogens. Over the 3 sampling points, 151 (85.8%), 178 (94.2%), 3 (1.5%), and 97 (57.4%) calves tested positive at least once for BCoV, BRoV A, BRoV B, and C. parvum, respectively. The source of the calves and the level of serum total protein measured on arrival were associated with testing positive for a pathogen. Calves that tested positive for C. parvum had an increased proportion of days with diarrhea and severe diarrhea; calves that tested positive for BCoV and BRoV A had an increased proportion of days with severe diarrhea. In addition, calves that tested positive for C. parvum had a higher hazard of being treated for respiratory disease. With respect to body weight, calves that had diarrhea or severe diarrhea had lower body weight at 49, 56, and 77 d. Specifically, calves that had an increased proportion of days with diarrhea showed a reduction in weight gain of up to 15 kg compared to calves without diarrhea. Calves that tested positive for C. parvum had a lower body weight at 49, 56, and 77 d; calves that tested positive for BCoV had a lower body weight at 56 and 77 d. This study demonstrates that the prevalence of BCoV, BRoV A, and C. parvum infection is high in this population of calves and has significant effects on the occurrence of diarrhea and body weight gain. Future studies should evaluate approaches for minimizing the effect of infection with these pathogens to improve the welfare, health, and productivity of dairy calves.     

Computer-controlled milk feeding of dairy calves: the effects of number of calves per feeder and number of milk portions on use of feeder and social behavior

One hundred ninety-two calves (Holstein-Friesian, Danish Red, and Jersey) were allocated to either groups of 24 calves or groups of 12 calves with one computer-controlled milk feeder per group. Within group, one-half of the calves were offered the daily milk allowance in either 4 or 8 milk portions. In groups with 24 calves, there was a higher level of competition for access to the feeder than in groups with 12 calves. Calves waited longer for access, and while occupying the feeder, they were more often disturbed by other calves attempting to access the feeder. The increased level of competition resulted in a higher rate of milk ingestion among calves in groups of 24 and, as a result, a lower duration of time spent ingesting the milk and a lower occupation of the feeder per calf. The number of calves per feeder did not affect the amount of milk ingested, but the high level of disturbance and the increased feeding rate with 24 calves per feeder suggest that these calves were subject to social constraint. Offering the same milk allowance in 4 rather than 8 milk portions lowered the occupancy of the feeder. The number of portions did not affect the duration of ingesting milk, but the duration of occupying the feeder just after milk ingestion was lower with 4 than with 8 milk portions. Thus, fewer and larger portions may lower competition for access during the activity periods if all other factors remain equal.     

Randomized clinical trial of the effect of a fixed or increasing milk allowance in the first 2 weeks of life on health and performance of dairy calves

The objective of this study was to describe the effect of offering a fixed or increasing milk allowance in the first 1 to 2 wk of life. We hypothesized that calves offered a fixed amount of milk early in life would not experience more scours, but rather would experience improved health and growth compared with calves that had their daily milk allowance slowly increased over a period of 1 to 2 wk. This randomized controlled clinical trial was conducted on 5 dairy farms in Minnesota with both a summer (June–August 2016) and winter (December–February 2017) period of enrollment. Heifer calves were enrolled at birth, weighed, and systematically assigned by birth order to either the slowly increasing (INC) control group or fixed allowance (FIX) treatment group by farm personnel. Calves assigned to the INC group were slowly increased from 4 to 5 L/d to gradually reach the full peak milk allowance of 6 to 8 L/d over a 7- to 14-d period, whereas calves assigned to the FIX group were offered a full peak milk allowance of 6 to 8 L/d beginning on d 1 after birth. The average FIX calf consumed an extra 14 L of milk as compared with INC calves over the first 2 wk of life, corresponding to an average INC intake of 5 L/d during first 1 to 2 wk of life as compared with an average intake of 6.8 L/d in FIX calves. Study technicians visited all farms weekly to collect health and performance data. Multivariable mixed models were used to describe the effect of treatment (INC/FIX) on 3-wk average daily gain (kg/d), 3-wk weight (kg), and hip height at wk 1, 3, and 7, controlling for the effect of season, birth weight, and the random effect of calf within farm. Multivariable logistic regression models were used to describe the effect of treatment on odds of technician and producer reported health events. A total of 1,264 heifer calves were enrolled (FIX n = 641; INC n = 623) with no difference in enrollment weight or hip height between groups. By 3 wk of age, FIX calves weighed 1.4 (0.59) kg more than INC calves, though the magnitude of this difference varied depending on the period of time INC calves were slowly increased in milk allowance (7 vs. 10 vs. 14 d). Calves in the FIX group grew 0.1 kg/d faster and were taller at wk 3 (0.3 ± 0.15 cm) of life. Forty-two percent (536/1,264) of all enrolled calves had a first treatment event, with no effect of treatment on technician-reported health scores and no overall effect on producer-reported treatment or mortality events. Under the conditions of this study, offering a fixed milk allowance from d 1 of life improved calf growth during the first 3 wk as compared with a gradual increase in milk allowance, with no detrimental effect on calf health.     

Effects of preweaning total plane of milk intake and weaning age on intake,growth performance,and blood metabolites of dairy calves

The objective of this study was to evaluate the effects of preweaning total plane of milk intake and weaning age on intake, growth performance, and blood metabolites of dairy calves. A total of 48 Holstein calves (40 ± 1.6 kg of body weight) were used in a 2 × 2 factorial arrangement with the factors of weaning age (d 60 vs. 75) and the total plane of milk intake (medium vs. high) during the preweaning period. Calves were assigned to 1 of 4 treatments: (1) calves fed medium plane of milk (MPM) intake and weaned on d 60 of age (MPM-60d, 4 L/d of milk from d 3 to 10, 6 L/d of milk from d 11 to 55, and 3 L/d of milk from d 56 to 60 of age; total milk intake = 317 L), (2) calves fed MPM intake and weaned on d 75 of age (MPM-75d, 4 L/d of milk from d 3 to 10 and 4.5 L/d of milk from d 11 to 70 of age followed by feeding 2.25 L/d of milk from d 71 to 75 of age; total milk intake = 313 L), (3) calves fed high plane of milk (HPM) intake and weaned on d 60 of age (HPM-60d, 4 L/d of milk from d 3 to 10, 6 L/d of milk from d 11 to 20, and 8.5 L/d of milk from d 21 to 55 followed by feeding 4.25 L/d of milk from d 56 to 60 of age; total milk intake = ～411 L); and (4) calves fed HPM intake and weaned on d 75 (HPM-75d, 4 L/d of milk from d 3 to 10, and 6 L/d of milk from d 11 to 70 of age followed by feeding 3 L/d of milk from d 71 to 75 of age; total milk intake = 407 L) with no milk refusals. All of the calves were monitored up to d 90 of age. Regardless of weaning age, starter feed intake and dry matter intake (% of body weight) were lower in calves fed HPM compared with those receiving MPM. A tendency for the plane of milk intake × weaning age interaction was observed for metabolizable energy intake with the highest value was recorded with the HPM-75d calves. The lowest efficiency of metabolizable energy intake and average feed efficiency was observed in HPM-60d calves throughout the experimental period as compared with the other groups. An interaction was found between the total plane of milk intake and weaning age regarding effects on total average daily gain, average daily gain/metabolizable energy intake, feed efficiency, final body weight, and plasma β-hydroxybutyrate levels with the highest values measured in HPM-75d calves. Weaning on d 75 versus d 60 improved wither height and hip width, which tended to increase body length at the end of the trial. The results suggest that calves fed high amounts of milk during their preweaning period benefit from extending the time of weaning from 60 to 75 d of age based on average daily gain, feed efficiency, and final body weight.     

The effect of increasing the nutrient and amino acid concentration of milk diets on dairy heifer individual feed intake,growth, development,and lactation performance

Increasing early (<3 mo) nutrient feeding levels and growth rate of dairy calves has been found to increase their milk production potential. The objective of this study was to compare the effect of offering milk diets with or without added carbohydrates and amino acids on calf growth, weaning age, and subsequent growth and milk yield of dairy heifers in their first lactation. Friesian calves born at Massey University (n = 57) were selected at random, weighed, and allocated to receive 1 of 3 diets. All calves were fed colostrum from 1 to 3 d of age, followed by 4 L of whole milk (WM) per head per day and probiotics between 3 and 18 d of age. At 18 d of age, calves were weighed to ensure mean body weight (BW); then, at 19 d of age, calves changed diets to 1 of 3 treatments, which reached full treatment rate at 21 d of age. The diets were 4 L/head per day of WM (M); 4 L/head per day of WM plus 200 g of plant carbohydrates (MP); and 4 L/head per day of WM plus 200 g of plant carbohydrates with amino acids (MPA). Calves were weaned upon reaching a BW of 90 kg. During this period, BW, body condition, and hip height and width were measured. The heifers were commingled and grazed on ryegrass and white clover pastures until calving at 23 mo of age, when BW, body condition, and hip height and width were measured again. Milk yield and composition were measured throughout first lactation. At weaning, calves fed MPA had greater mean BW gain, a lower number of days to target BW, and a greater mean hip width gain compared with calves in the M group, although mean gain in hip height did not differ among treatments. Total calf starter intake during the milk period was lower for MPA-fed calves compared with those offered M, mainly due to a shorter milk feeding period required to attain the 90-kg weaning weight, whereas mean daily starter intake and straw intake did not differ. No difference was observed in the calving rate or calving age of heifers in any of the dietary feeding groups. First lactation fat-corrected milk yield, milk fat percentage, and total milk fat and protein yields were greater for animals reared on MP and MPA compared with M. Body weight, hip height and width at parturition, milk protein percentage, somatic cell count, or days in milk did not differ among treatments. Increasing nutrient intake, during the milk feeding period, improved the BW gain of calves and milk production of dairy heifers during first lactation.     

The effect of a furnished individual hutch pre-weaning on calf behavior,response to novelty,and growth

Housing preweaned dairy calves in individual outdoor hutches is common in North America. However, this type of housing lacks stimulation and minimizes calves' ability to express natural behavior. Providing a social companion has been shown to stimulate natural behavior and promote growth, but no research has assessed the effect of providing physical enrichment items to calves pre-weaning. The objective of this study was to determine calf use of physical items added to an individual hutch, and if providing these items affected growth, behavior (e.g., locomotor play and sucking on pen fixtures), and response to novelty after weaning. At birth, Jersey heifer calves were allocated to 1 of 2 types of hutches: furnished (n = 9 calves) or standard (n = 10 calves). Calves were housed in individual hutches on loose gravel and bedded with straw. The outdoor enclosure of furnished hutches contained 2 artificial teats, a stationary brush, a calf “lollie,” and a rubber chain link for calves to manipulate. Calves were video-recorded continuously between 0800 and 2000 h twice weekly at 1, 3, 5, and 7 wk of age; behavioral data were collected using the Noldus Observer software program (Noldus Inc., Wageningen, the Netherlands). At 63 d of age (after weaning), calf response to social and environmental novelty was tested. Starter consumption was measured daily, and calves were weighed at birth and weekly thereafter. Pre-weaning behavioral data were not normally distributed, so raw data were square-root-transformed before analysis. Calves used all of the items depending on the time of day, but they spent the most time using the brush. Calves housed in furnished hutches spent almost 50% more time engaged in locomotor play, but they spent the same amount of time sucking pen fixtures as calves housed in standard hutches. We observed no effect of treatment on growth, starter intake, or behavioral response to social and environmental novelty after weaning. Results suggest that providing some physical complexity to a standard hutch has some benefits for young calves, but further research is encouraged to determine the long-term effects of physical and social complexity for young dairy heifer calves.     

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.