Milk Allowance Research Articles

PSVIII-26 Utilizing Megasphaera elsdenii probiotic to improve the performance of crossbred Holstein x Angus calves

Abstract This study evaluated the effect of an oral probiotic bolus (Megasphaera elsdenii NCIMB 41125; Lactipro Advance®, MS Biotec, Wamego, KS) on the performance of crossbred Holstein x Angus calves. Thirty-one calves (45.3 ± 7.1 kg; 8.2 ± 2.0 d old) were enrolled in a 76-day randomized block trial in two blocks. This study was conducted at the University of Kentucky Large Animal Unit between August 2020 and April 2021. Calves were assigned to one of three probiotic treatments: no probiotic (ME0), single dose of probiotic on day 15 (ME15), or probiotic administration on day 15 and 39 (ME15 + 39). Calves were individually housed and had ad libitum access to water and a pelletized calf starter (18% CP, 2.5% fat). Calves were fed 7 L/d of milk replacer (Cows Match Warm Front, Land O Lakes, MN; 1L, 150 g/L) divided into two equal meals until day 41. On day 42, milk allowance was reduced in half and then weaned on day 56. Grain orts were weighed daily and grain intake was calculated for each calf. Individual body weights were measured weekly. A mixed linear model determined the effect of treatment on total grain dry matter intake (total DMI), total weight gain (TWG), average daily gain (ADG), and feed conversion ratio (FCR). Manual stepwise backward elimination retained predictors with a P-value < 0.30 of the factors block, treatment, age and weight at enrollment, and if treated with antibiotics. Calves receiving the M. elsdenii bolus had greater TWG (ME0=53.57±5.83, ME15=72.52±6.71, ME15 + 39=77.51±5.00 kg; P = 0.01), greater ADG (ME0=0.73±0.08, ME15=0.99±0.09, ME15 + 39=1.05±0.07 kg/d; P = 0.01), and tended to have greater total DMI (ME0=72.24±10.49, ME15=95.20±12.07, ME15 + 39=105.36±9.01 kg; P = 0.06) throughout the study. FCR did not differ between treatments (ME0=0.79±0.04, ME15=0.78±0.04, ME15 + 39=0.76±0.03 kg; P = 0.84). Overall, strategic pre-weaning intervention of a M. elsdenii bolus improved the performance of crossbred Holstein x Angus calves.

Effects of delaying increase in milk allowance and type of gradual weaning program on performance and health of calves fed lower levels of milk

The objective of this study was to investigate the effects of delayed increase in milk allowance and type of gradual weaning program on the feed intake, health, and growth of male Holstein calves. Using a 2 × 2 factorial design, each male Holstein calf was randomly assigned to 1 of 2 milk level treatments and 1 of 2 weaning treatments upon arrival to a rearing facility. Calves were either assigned to a moderate (MM) or lower (LM) milk level treatment. All calves received the same milk program from arrival until d 12, increasing from 4 to 5 L/d (115 to 125 g/L) over the 12 d. On d 13, MM calves began receiving additional milk compared with LM calves until they were weaned, with MM offered milk increasing to a peak of 9 L/d (140 g/L). Calves on the MM treatment received a total of 35 kg of milk replacer over 45 d, compared with LM calves, who received a total of 25 kg of milk replacer over 45 d. Calves were also assigned to be weaned by either a 2-step gradual program or a 4-step gradual program. Calves assigned to the 2-step program had their milk reduced in 2 steps from d 30 to 45, and 4-step calves had their milk reduced in 4 steps from d 30 to 45. After d 46, calves received no milk but continued to be monitored until d 59. Calves had ad libitum access to water from arrival, and solid feed was offered from d 5 onward. No interactions of effects of milk level and weaning treatment were detected. By design, calves on the MM treatment consumed greater amounts of milk than LM calves in the preweaning phase from d 13 to 29 (6.1 vs. 4.8 L/d) and weaning phases from d 30 to 45 (4.7 vs. 3.2 L/d). The LM calves consumed greater amounts of solid feed than MM calves from d 22 to 29 of the preweaning phase, and from d 30 to 40 and d 43 to 45 of the weaning phase, whereas postweaning feed consumption was similar for both milk treatments. Calves in both milk treatments had similar blood β-hydroxybutyrate levels, indicating similar rumen development. Body weight and size measurements were similar between milk treatments across the study, although LM calves had a greater average daily gain than MM calves between d 38 and 46 (0.96 vs. 0.71 kg/d). Both gradual weaning treatments resulted in similar feed consumption, growth, and health parameters. Overall, the results indicate that delaying a moderate increase in milk until 12 d after arrival at a rearing facility provided no overall beneficial effect on growth or rumen development.

Associations between feeding behaviors collected from an automated milk feeder and disease in group-housed dairy calves in Ontario: A cross-sectional study

The adoption of automated milk feeders and group housing of preweaning dairy calves has become more common in Canada; however, disease detection in group-housed calves remains a challenge. The aim of this cross-sectional study was to assess whether feeding behavior data collected from a single point in time could be used to aid in the detection of neonatal calf diarrhea (NCD), bovine respiratory disease (BRD), and general disease, in preweaning group-housed calves being fed via an automated milk feeder. The data used was collected in an earlier study. A total of 8 dairy farms recruited from an online survey of calf-management practices were enrolled into the study. There was a total of 523 observations with 130 events of NCD, 115 events of BRD, and 210 events of general disease. Each farm was visited once in each of the fall, winter, spring, and summer, when the calves' health was scored, and the data were collected from the automated milk feeders. Mixed linear regression models were used to identify associations between feeding behavior data (milk consumption, time spent at the feeder, drinking speed, and the number of rewarded and unrewarded visits) and the presence of NCD, BRD, or general disease (having one or more of NCD, BRD, or umbilical infection), on the day of health scoring. Generalized linear mixed models were used to analyze the percentage of milk the calf consumed from their daily milk allotment. Calves with BRD consumed 63% less of their daily allotment of milk, had 2 fewer unrewarded visits to the automated milk feeder, and drank milk 152 mL/min slower compared with calves without BRD. Calves with NCD consumed 57% less of their daily milk allotment, consumed 758 mL less per day, and drank 92 mL/min slower than calves compared with calves without NCD. Calves with general disease drank 50% less of their daily milk allowance, consumed 496 mL less per day, drank 80 mL/min slower, and had 2 fewer unrewarded visits to the automated milk feeder, when compared with calves without disease. No significant associations were found between the presence of NCD, BRD, or general disease and time spent at the feeder or number of rewarded visits. Sensitivity and specificity values for disease identification were low when evaluating the feeding behaviors individually, so parallel testing was completed. To do so, if any significant feeding behavior was below the optimal cut point for disease detection as determined using a ROC curve, the calf was considered positive for disease and the sensitivity and specificity were recalculated. Parallel testing resulted in a sensitivity of 0.82, 0.78, and 0.84, and a specificity of 0.26, 0.23, and 0.21, for BRD, NCD, and general disease, respectively. This suggests that automated milk feeders may serve as a useful preliminary tool in the detection of diseased calves. For example, producers could use feeding behavior data to identify calves requiring further inspection; however, they should not use feeding behavior data as a sole disease detection method.

76 Growth and Health of Limousin Crossbred Dairy-beef Calves in an Automated Feeding System

Abstract The objective of this study was to determine growth and health of Limousin crossbred dairy-beef calves fed alternative milk allowances in an automated group feeding system. The study was conducted at the University of Minnesota West Central Research and Outreach Center’s, Morris, MN dairy. Forty-eight Limousin-sired crossbred calves were assigned to feeding groups by birth order during two calving seasons from September to December 2019 and March to July 2020. Calves were introduced to the Holm & Laue HL100 Programmable Calf Feeder (Holm & Laue GmbH & Co KG, Westerronfeld, Germany) at 5 d and were randomly assigned to one of two treatments. Treatments for calves were 8 L/d (8L) or ad libitum (AL) milk allowance. Calves were weaned from the automated feeder at 56 d. Data were analyzed using PROC MIXED of SAS. Independent variables for analyses were the fixed effects of season of birth, sex of calf (M or F), treatment group and sex of calf nested within season of birth was a random effect. No differences (P > 0.05) were found between 8L or AL groups for birth weight. The AL calves (109.4 kg) had higher (P < 0.01) weaning weight than 8L calves (95.3 kg). Furthermore, the AL calves had higher (P < 0.01) hip height (95.6 cm) and greater (P < 0.01) heart girth (110.2) compared with 8L calves (93.8 cm and 104.8 cm, respectively). The AL calves (1.14 kg/d) had higher average daily gain at weaning compared to 8L calves (0.91 kg/d). Males calves were not different (P = 0.39) for average daily gain compared to female calves (1.07 kg/d versus 0.98 kg/d). Drinking speeds of AL calves were lesser (P < 0.05; 1,222 mL/min) than the 8L calves (1,453 mL/min). The AL calves and 8L calves were not different for hygiene scores or health scores. The results from this study indicate advantages to feeding dairy-beef calves ad libitum whole milk during the pre-weaning period.

Using compositional mixed-effects models to evaluate responses to amino acid supplementation in milk replacers for calves

The consequences of supplementing Lys, Met, and Thr in milk replacers (MR) for calves have been widely studied, but scarce information exists about potential roles of other AA (whether essential or not). The effects on growth performance of supplementation of 4 different AA combinations in a mixed ration (25.4% crude protein and 20.3% fat) based on skim milk powder and whey protein concentrate were evaluated in 76 Holstein male calves (3 ± 1.7 d old). The 4 MR were as follows: CTRL with no AA supplementation; PG, supplying additional 0.3% Pro and 0.1% Gly; FY, supplying additional 0.2% Phe and 0.2% Tyr; and KMT, providing additional 0.62% Lys, 0.22% Met, and 0.61% Thr. All calves were fed the same milk allowance program and were weaned at 56 d of study. Concentrate intake was limited to minimize interference of potential differences in solid feed intake among treatments. Animals were weighed weekly, intakes recorded daily, and blood samples obtained at 2, 5, and 7 wk of study to determine serum urea and plasma AA concentrations. Plasma AA concentrations were explored using compositional data analysis, and their isometric log-ratio transformations were used to analyze their potential influence on ADG and serum urea concentration using a linear mixed-effects model. We detected no differences in calf performance and feed intake. Plasma relative concentration of the AA supplemented in the KMT and PG treatments increased in their respective treatments, and, in PG calves, a slight increase in the proportion of plasma Gly, Glu, and branched-chain AA was also observed. The proportions of plasma branched-chain AA, His, and Gln increased, and those of Thr, Arg, Lys, and Glu decreased with calves' age. A specific log-contrast balance formed by Arg, Thr, and Lys was found to be the main driver for lowering serum urea concentrations and increasing calf growth. The use of compositional mixed-effects models identified a cluster formed by the combination of Arg, Thr, and Lys, as a potential AA to optimize calf growth.

Effect of milk allowance on the suitability of automated behavioural and physiological measures as early disease indicators in calves

This study investigated the effect of milk allowance on the suitability of behavioural and physiological responses, individually and in combination, as early disease indicators. A total of 120 heifer calves were assigned into a 5 L/d or 10 L/d milk allowance treatment group. Daily health checks were conducted to determine when calves presented clinical signs of neonatal calf diarrhoea (NCD). Automated calf feeders recorded milk feeding behaviour, and infrared cameras automatically recorded eye and cheek temperatures. Accelerometers recorded lying behaviour, and water drinking behaviour was recorded using an automated water system and video observations. Respiration rate was recorded once per day by counting flank movements. Calves were used as their own controls, with data analysed relative to the day of clinical identification (d 0). Based on changes which occurred over the 6 days prior to clinical signs of disease (across d -6 to 0), typically, feeding behaviours only changed significantly for calves on the 10 L/d milk allowance with an increase in total (P < 0.001) and rewarded visits to the feeder (P = 0.013), and a decrease in milk consumption (P = 0.011). Infrared temperatures only changed significantly prior to clinical signs for calves on the 5 L/d milk allowance, with a decrease in eye (P = 0.013) and cheek (P = 0.006) temperatures. Regardless of milk allowance, lying time (P = 0.028, 5- L/d; P = 0.011, 10 L/d), number of lying bouts (P < 0.001, 5 L/d; P = 0.007, 10 L/d), and average bout duration (P < 0.001, 5 L/d; P = 0.002, 10 L/d), changed significantly prior to clinical signs. The only significant change in water drinking behaviour prior to clinical signs was an increase in total trough visit duration for calves on the 5 L/d milk allowance (P = 0.029). Respiration rate showed no significant change prior to clinical signs regardless of milk allowance. For calves on the 10 L/d and 5 L/d milk allowances, the most suitable indicator of disease was the total number of visits to the feeder (P < 0.001) and the number of lying bouts (P < 0.001), respectively. Regardless of milk allowance, combinations of feeding and lying behaviours, and additionally infrared temperatures in the case of calves on the 5 L/d milk allowance, provided the strongest composite indicators of disease. Overall, results suggest milk allowance can influence the suitability of behavioural and physiological responses as early disease indicators. Milk allowance should be considered when determining which measures will act as the optimum indicator/s when developing and implementing algorithms into automated on-farm systems for disease detection.

Negative play contagion in calves

Play is a strong outwardly directed, emotional behaviour and can contagiously spread between individuals. It has been suggested that high-playing animals could ‘seed’ play in others, spreading positive affective states. Despite the current interest in play contagion there has been no previous attempt to measure the strength of the play contagion effect. The calf (Bos taurus) is ideal for testing the strength of play contagion as play in calves is strongly related to energy intake from milk. We manipulated play in calves through their milk allowances and housed the calves in uniform groups all on the same milk allowance (high = UHigh or low = ULow) or in mixed groups with calves in the same group receiving either a high (= MHigh) or low (= MLow) milk allowance. We measured locomotor play using accelerometers on two consecutive days when calves were four and eight weeks old, in order to study play contagion over a protracted developmental window. We anticipated that differences in the level of play contagion between treatment groups would result in difference in the play levels observed in the MLow and ULow individuals. Contrary to our expectations we found that spontaneous play was suppressed in the high-milk calves housed in mixed groups (MHigh), in comparison to calves housed with group mates all receiving high-milk (UHigh). These results are the first to quantify a negative play contagion effect, particularly in a situation of long-term contact, and may suggest that negative contagion has a stronger effect on play behaviour than positive contagion.

Effects of physical forms of starter and milk allowance on growth performance, ruminal fermentation, and blood metabolites of Holstein dairy calves

A 2 × 2 factorial study was conducted to evaluate the effects of milk allowance and physical forms of starter on growth performance, ruminal fermentation, and blood metabolites of Holstein dairy calves. A total of 48 calves [40.4 ± 1.55 kg of body weight (BW), n = 12 per treatment: 6 males and 6 females] were randomly assigned to 1 of the 4 treatments: (1) calves fed low milk allowance and finely ground (FG) starter feed [low-FG; 1.47 ± 2.12-mm geometric mean particle size (GMLP)], (2) calves fed low milk allowance and textured (TS) starter feed [low-TS, includes steam-flaked grains (corn and barley) with a pelleted supplement, GMLP 4.15 ± 1.77 mm], (3) calves fed high milk allowance and FG starter feed (high-FG); and (4) calves fed high milk allowance and TS starter feed (high-TS). The starter diets were blended with 7% of chopped alfalfa hay as a proportion of diet dry matter (DM). No milk refusal was observed in any treatments, and calves on both treatments were weaned from milk by wk 8 of the study using a gradual weaning procedure. We observed no interaction between milk allowance and physical forms of starter on feed intake, average daily gain, feed efficiency, BW, and structural growth. Calves fed high milk allowance had lower starter feed intake but greater feed efficiency and overall BW compared with those fed low allowance. Total DM intake and average daily gain were not different among treatments. Regardless of the physical form of starter feed, hip height, heart girth, the molar proportion of ruminal acetate, acetate to propionate ratio, plasma cholesterol, and high-density lipoprotein were greater, but ruminal total volatile fatty acids, the molar proportion of propionate, and plasma β-hydroxybutyrate were lower in calves fed high milk allowance compared with those fed low allowance. Regardless of the milk allowance, calves fed the FG starterfeeds had greater blood urea nitrogen concentrations compared with calves fed the TS starter diets. In conclusion, both forms of the starter feeds can be used when calves are fed high milk allowance with no negative effect on their performance.

The effect of milk feeding strategy and restriction of meal patterning on behavior, solid feed intake, and growth performance of male dairy calves fed via computer-controlled milk feeders

Dairy calves are often offered milk allowance at a flat rate during the first 6 wk of life, although an initial high allowance followed by a stepwise reduction (step-down strategy) may correspond better to the calves' nutritional needs. The amount of milk offered per feeding is typically constant. However, during natural suckling, the daily number of milk meals (suckling frequency) declines with age, which may reflect increased consumption of solid feeds. Thus, allowing calves to pattern their meals on a computer-controlled feeder by placing less restriction on meal frequency may stimulate dairy calves' ingestion of solid feeds. This experiment investigated the effects of milk feeding strategy and milk feeding frequency on calves' feeding behavior, intake, and growth. Sixty-four male Holstein Friesian calves, purchased from conventional dairy farms, were housed in groups of 8 and fed milk replacer (MR) via computer-controlled milk feeders. From 14 d old, calves were assigned to either a conventional flat-rate milk allowance (CON: 6.5 L/d of MR from d 14 to 42; 4 L/d from d 43 to 49; 2 L/d from d 50 to 56 of age) or to stepwise reduction in milk allowance (STEP: 8 L/d of MR from d 14 to 28; 5 L/d from d 29 to 42; 4 L/d from d 43 to 49; 2 L/d from d 50 to 56 of age). Within each group of 8, 4 calves were randomly allocated to each of 2 milk feeding frequencies, either restricted portion size (RES: maximum milk portion size of 2.3 L/portion) or unrestricted portion size (UNRES). Concentrates, hay, and water were available ad libitum. Feeding behavior was recorded via video for 24 h on 26 and 40 d of age. On d 26, where STEP calves were offered 1.5 L/d more milk than CON calves, no difference was seen regarding the time spent eating concentrate (16.9 vs. 20.3 min/d). However, STEP calves spent more time eating concentrate on d 40, where these calves had 1.5 L/d less milk than CON (36.1 vs. 27.2 min/d). Thus, a lower daily milk allowance stimulated feeding on concentrate d 40, but not d 26. As predicted, UNRES calves spent more time eating concentrate (27.6 vs. 21.9 min/d) and more time eating hay (38.4 vs. 30.0 min/d) than RES calves. However, higher appetite for solid feeds by UNRES calves may not be explained by milk intake per se. Rather, this is likely due to their opportunity to have larger milk meals, which appeared to increase their appetite for milk (as indicated by longer time spent in the milk feeder; 64.0 vs. 48.8 min/d) as well as for solid feeds. Among CON calves, the UNRES treatment resulted in higher ADG 2 wk postweaning, but not among STEP calves. These findings partially support that relaxing restriction on milk portions helps calves to transition from milk to solid feeds before weaning off milk. However, more research is needed to determine how restriction on milk portions interacts with milk feeding strategy when a higher total milk allowance is offered.

Effect of arginine or glutamine supplementation and milk feeding allowance on small intestine development in calves

The development of the small intestine (SI) is important for the health and growth of neonatal calves. This study evaluated the effect of arginine (Arg) and glutamine (Gln) supplementation and 2 levels of milk allowance on the histomorphological development of the SI in preweaning calves. Sixty mixed-sex Friesian × Jersey calves (3-5 d of age) were offered reconstituted whole milk (125 g/L, 26% fat, 26% protein) at either high (20% of arrival body weight/d; HM) or low (10% of arrival body weight/d; LM) milk allowance without (Ctrl) or with supplementary Arg or Gln (at 1% of milk dry matter) in a 2 × 3 factorial design (n = 10/treatment). After 35 d on the diets, all calves were slaughtered to collect tissues for examination of SI development. Calves in the HM group had higher milk intake, total weight gain, and average daily gain compared with LM calves, but no effect of AA supplementation nor an interaction between milk allowance and AA supplementation was observed. For the duodenum, we observed an AA by milk allowance interaction for villus height and width, and goblet cell number per villus (HM-Arg > HM-Gln > HM-Ctrl), and villus height to crypt depth ratio (HM-Arg > HM-Gln = HM-Ctrl), but no effect of AA supplementation in the LM group. Goblet cell numbers per 100 µm of SI were greater in Arg-supplemented calves than in unsupplemented controls, with Gln-supplemented calves intermediate to but not different from the other groups. Epithelium thickness was greater in LM than in HM calves. Villus density, crypt depth, and muscle thickness did not differ between groups. For the jejunum, there was an AA by milk allowance interaction for villus height, villus surface area, and villus height to crypt depth ratio (HM-Arg = HM-Gln > HM-Ctrl), with no effect of AA supplementation in the LM groups. Amino acid supplementation affected goblet cell number per villus (HM-Gln > HM-Ctrl calves, HM-Arg intermediate), and both LM-Arg and LM-Gln calves had greater numbers than LM-Ctrl calves. Villus width, crypt depth, and muscle thickness were greater in HM than LM calves but there was no effect of AA supplementation. Villus density, goblet cell number per 100 µm of SI, and epithelium thickness were unaffected by AA supplementation and milk allowance. Milk allowance and AA supplementation had no effect on SI morphology in the ileum. Increasing milk allowance improved villus height, width, and surface area but only in Arg- or Gln-supplemented calves, not in control calves. The observed changes in development may be important for intestinal functionality, integrity, and barrier function in preweaning calves, potentially through increased cell growth and proliferation or reduced levels of cellular atrophy.

Health and growth of veal calves provided a fatty acid supplement and a dry teat

Veal calves are at a high risk of disease early in life, which can lead to poor growth. Research is needed to determine interventions that can reduce disease and promote the growth of veal calves. The aim of this study was to determine the effects of fatty acid supplementation and the provision of a dry teat on the incidence of bovine respiratory disease (BRD), navel inflammation, and diarrhea, as well as calf growth. Upon arrival to a commercial veal facility (d 0), 240 Holstein bull calves from 2 cohorts were randomly assigned to 4 treatments using a 2 × 2 factorial arrangement (n = 60/treatment): (1) milk replacer (MR) without fatty acid supplementation and without access to a dry teat (control), (2) MR with fatty acid supplementation (NeoTec5g, Provimi, Brookville, OH) and without access to a dry teat (FAS), (3) MR without fatty acid supplementation and with access to a dry teat (TT), or (4) MR with fatty acid supplementation and with access to a dry teat (FAS+TT). Calves were housed in individual pens from 0 to 9 wk and then paired by treatment at wk 9. Milk replacer was fed twice daily using a step-up program. Fatty acid supplement was added to milk replacer at a feeding rate of 0.5 g/kg of body weight per head per day for the FAS and FAS+TT groups. Health exams were conducted twice weekly for 6 wk to diagnose BRD, navel inflammation, and diarrhea. Body weight, body condition score (BCS), and structural measurements were recorded at wk 0, 5, and 10. Average daily gain (ADG) was calculated for wk 1 to 5, wk 5 to 10, and wk 1 to 10. Health data were analyzed using logistic regression and are reported as relative risk. Body weight, BCS, and structural measurements were analyzed using repeated-measures ANOVA, and ADG was analyzed using a generalized linear model. There was no effect of FAS, TT, or their interaction on body weight or BCS. There was no effect of FAS on ADG wk 1 to 5, wk 5 to 10, or wk 1 to 10. There was a tendency for TT to decrease ADG from wk 1 to 5 but not from wk 5 to 10 or wk 1 to 10. There was a tendency for the interaction of FAS and TT to decrease ADG for wk 1 to 5 but not for wk 5 to 10 and wk 1 to 10. There was no effect of FAS, TT, or their interaction on the risk of BRD, diarrhea, or navel inflammation. We saw no effect of our interventions on calf health or growth. More research is needed to determine whether other factors, such as failure of passive transfer, poor ventilation, barren housing, and low milk allowance in the first few weeks after arrival, may have affected the efficacy of our interventions.

Appropriate Dairy Calf Feeding from Birth to Weaning: "It's an Investment for the Future".

Simple SummaryResearch has indicated that dairy farms often do not feed calves according to recommended best practice, despite legislation and industry advisory efforts. This study used interviews with dairy farmers and their advisors to investigate why farmers feed calves the way they do. Various calf feeding practices were used by participating farmers, largely based on perceived convenience and calf performance. Advisors were concerned that calves were commonly underfed, which may be partly due to farmers receiving inadequate instructions for calf feeding. Our results highlight the need for more consistent and effective recommendations for farmers regarding calf feeding and weaning. Standard guidelines for calf milk replacers should be improved to ensure that calves are fed enough to support basic biological functions and growth. Further research is needed to establish best practices for weaning calves whilst supporting rumen development, health and weight gain. All recommendations for calf feeding should facilitate the achievement of standard industry targets including rearing replacement dairy heifers to calve by 24 months of age. Dairy calves must be fed appropriately to meet their nutritional needs, supporting optimal growth and development to achieve the recommended target age at first calving (AFC) of 24 months. Traditional restricted milk feeding practices suppress growth, contribute to negative welfare states and may result in malnutrition and immunosuppression. Despite more recent recommendations to increase milk allowances for pre-weaned calves, restricted feeding remains a common practice. This study explored the rationales behind the calf feeding protocols used by dairy farmers in England. Forty qualitative interviews (26 farmers, 14 advisors) were conducted between May 2016 and June 2017, transcribed in full, then coded into themes. Results indicate that a variety of calf feeding regimes are used on farms, largely determined by farmers’ attitudes regarding ease of management and the wellbeing of calves. Advisors were concerned about widespread underfeeding of calves, which may be partially due to insufficiently clear recommendations for calf milk replacer (CMR) feeding rates. There was also evidence of uncertainty regarding best practices for weaning calves. Collaboration between academic research and industry is essential to establish a consensus on calf feeding standards which support physiological function, facilitate weaning, support growth targets and ensure calf health and welfare is protected.

The effect of milk quantity and feeding frequency on calf growth and behaviour

Context Calves left with their dam to suckle will consume ~7–12 L/day; however, the amount of milk provided to dairy young calves removed from their dams may often be as low as 4 L/day, or 10% of their bodyweight. Aims This study compared once and twice daily feeding, as well as feeding levels of 10 and 20% of bodyweight and studied the effect on behaviour and metabolic indicators indicative of hunger. Methods Forty-six male dairy calves were allocated to one of three treatments from 3 to 8 days of age: (i) 10% of bodyweight offered daily as one meal (1 × 10%, n = 16); (ii) 10% of bodyweight offered daily over two meals (2 × 5%, n = 15); or (iii) 20% of bodyweight offered over two meals (2 × 10%, n = 15). Behaviour during and after feeding was observed by video, and blood samples taken on selected days were analysed for glucose, nonesterified fatty acids (NEFA), cortisol and packed-cell volume. Key results Milk intake on Days 3 and 4 was lower in those calves fed once daily compared with calves fed twice daily. Calves fed at 20% bodyweight had higher milk intake compared with calves fed at 10% bodyweight on all days other than Day 3 and growth was higher in those calves. Non-nutritive sucking was mainly associated with feeding times and it was highest in calves fed 10% bodyweight over two meals, with a suckling pattern that suggested that feeding at 10% bodyweight satisfied feeding motivation less than feeding at 20% bodyweight. Play behaviour was reduced in calves fed once daily, suggesting hunger and reduced welfare. There were significant effects on physiological indicators of metabolic state. NEFA concentrations were significantly higher in calves fed once daily and calves fed 10% of bodyweight at certain time points, indicating a lower energy balance. Conclusions Feeding twice daily offers benefits to calves up to Day 4 of life whereas feeding 20% of bodyweight was beneficial after Day 4 to increase satisfaction of feeding motivation and nutrition for growth. Although metabolic variables were within normal physiological range for all treatments, the effects on feed intake, growth and non-nutrient sucking suggest marked effects on hunger when calves are fed the lower milk allowance. Implications The fairly common practice of feeding dairy calves 10% of bodyweight, in one or two daily meals may leave calves hungry, and an increase in milk allowance should be considered.

Effects of intensified or conventional milk feeding on pre-weaning health and feeding behavior of Holstein female calves around weaning.

Health, inflammatory, and stress indices as well as feeding behavior around weaning were measured for Holstein female calves fed intensified milk or conventionally during the pre-weaning period. Calves (n ꞊ 48) were randomly assigned to one of two experimental treatments including a conventional (CF) or an intensified feeding (IF) groups. In CF group, calves (n ꞊ 24) received 0.52 kg of dry matter (DM) per day from pasteurized whole milk (23.00% crude protein (CP) and 27.00% fat) until day 50 of age. In IF group, calves (n = 24) fed 0.97 kg of DM per day on average for the first three weeks, and then, milk allowance decreased gradually to reach 0.52 kg DM per day and continued until day 50. All calves were gradually weaned from day 51 to 56. Blood samples were taken on days 14, 28, and 57 at 06:30 AM for serum amyloid A (SAA), cortisol, alanine aminotransferase (ALT), and iron analyses. Conventionally fed calves had more days with fever during the pre-weaning period. Blood SAA and cortisol levels were higher in CF calves on day 14. However, SAA levels were higher for IF calves on day 57. Intensified milk-fed calves spent more time for standing than CF calves. A trend to be significant was observed for non-nutritive oral behavior in IF calves. In summary, dairy calf health can be improved by intensified milk feeding during the pre-weaning period; however, this method has the potential to reduce calves welfare around weaning transition.

The effects of feeding high or low milk levels in early life on growth performance, fecal microbial count and metabolic and inflammatory status of Holstein female calves

Gut microbial colonization and immune response may be affected by milk feeding method. The objective of this study was to determine the effects of feeding high or low volumes of milk on fecal bacterial count, inflammatory response, blood metabolites and growth performance of Holstein female calves. Colostrum-fed calves (n = 48) were randomly assigned to either high milk (HM; n = 24) or low milk (LM; n = 24) feeding groups. Low milk-fed calves were fed pasteurized whole milk at 10% of BW until weaning. In HM group, milk was offered to calves at 20% of BW for the first 3 weeks of life. Then, milk allowance was decreased gradually to reach 10% of BW on day 26 and remained constant until weaning on day 51. Calves were allowed free access to water and starter throughout the experiment. Body weight was measured weekly, and blood samples were taken on days 14, 28 and 57. Fecal samples were collected on days 7, 14 and 21 of age for the measurement of selected microbial species. By design, HM calves consumed more nutrients from milk during the first 3 weeks and they were heavier than LM calves on days 21, 56 and 98. High milk-fed calves had greater serum glucose and triglyceride levels on day 14 with no significant difference between groups on days 28 and 57. Blood urea nitrogen was higher in LM calves on day 14, but it was lower in HM calves on day 28. Calves in LM group had significantly greater blood tumor necrosis factor-α (TNF-α) than HM calves throughout the experiment. Serum amyloid A (SAA) concentration was higher in LM calves on day 14. However, HM calves showed higher levels of SAA at the time of weaning. Feeding high volumes of milk resulted in lower serum cortisol levels on days 14 and 28 but not at the time of weaning in HM calves compared to LM counterparts. Lactobacillus count was higher in feces sample of HM calves. Conversely, the numbers of Escherichia coli was greater in the feces of LM calves. Calves in HM group showed fewer days with fever and tended to have fewer days treated compared to LM group. In conclusion, feeding higher amounts of milk during the first 3 weeks of life improved gut microbiota, inflammation and health status and growth performance of Holstein dairy calves.

187 Utilizing automation to improve efficiency, health, and production in the dairy industry

Abstract The dairy industry has an increasing availability of equipment that is readily available for the automation of management tasks, including milking and feeding, as well as the monitoring of dairy cow behavior. Such automation not only has the ability to improve production and time efficiency on farm, but also increases our ability to monitor individual cows. Rapid adoption of automated (robotic) milking systems (AMS) is a good example of such benefits. Producers who have adopted this technology suggest they gain more time flexibility, find work to be less stressful and physically demanding, and report improved quality of their own life as well as that of their cows. At the same time, adoption of AMS may be associated with improvements in cow health and productivity. Similar findings apply for the adoption of automated milk feeders for dairy calves. The adoption of automated milk feeders has been done in effort to provide higher milk allowances, and thus raise healthier and better growing calves, reduce labor, and improve working conditions on farm. While less studied, automation in feeding of lactating cows also holds much promise for improving feeding accuracy and precision; thus not only reducing labor needs, but also having positive effects on cow production and efficiency. Finally, there is also rapid adoption of automated technologies for individual behavioral monitoring of dairy cows. These technologies have widely been adopted for estrus detection. In addition, they are also useful for detection of health disorders, both in occurrence and in advance of clinical symptoms. This, in turn, allows producers to identify and implement prevention and treatment protocols at earlier time points. It is anticipated that in the future such behavioral monitoring will play a larger role in terms of informing management decisions on farm.

Key animal welfare issues in commercially raised dairy calves: social environment, nutrition, and painful procedures

Dairy calf welfare concerns are growing and new evidence suggests that the early life environment influences appropriate physical, behavioral, and cognitive development lasting into adulthood. This review highlights key evidence for the impacts of housing, diets, and painful procedures on calf welfare. We argue that these topics are currently critical welfare concerns, but are not the only points of concern. In addition to environmental requirements to maintain optimal health, dairy calves experience other challenges including social and nutritional restrictions. Individual housing is associated with impaired behavioral development and cognitive ability. Pair and group housing can mitigate some of these negative effects and should be encouraged. Restrictive milk allowances (&lt;15% of body weight) lead to poor growth and hunger; these welfare concerns can be addressed with proper enhanced milk allowances and gradual weaning programs. Finally, dehorning is a critical animal welfare issue when pain control is withheld; calves show negative behavioral, physiological, and emotional responses during and after dehorning. The combined use of local anaesthetics and analgesics can mitigate these effects. An industry shift toward providing social companionship, enhanced milk allowances, and pain control during painful procedures would help to improve the welfare of dairy calves in intensive commercial rearing facilities.

Effects of milk replacer feeding levels on performance and metabolism of preweaned dairy calves during summer

The objective of this study was to evaluate the effect of milk replacer (MR) feeding programs on performance and metabolism during summer. At 3 d of age (DOA), calves were randomly assigned to 1 of 4 dietary treatments: control [CON; 0.55 kg dry matter (DM) of a 20% crude protein (CP) and 20% fat MR per day], intermediate (IL; 0.66 kg DM of a 26% CP and 17% fat MR per day), high (HL; 0.77 kg DM of a 26% CP and 17% fat MR per day), or aggressive (AL; 0.87 kg DM of a 26% CP and 17% fat MR per day). Calves were managed similarly and housed in individual polyethylene hutches using sand as a bedding material. Because 3 calves fed the AL diet developed abomasum bloating during the first 30 DOA, the AL treatment was terminated. Milk replacer (12.5% solids) was offered twice daily until 42 DOA, when MR was fed once daily to reduce its intake by 50%. Calves were weaned at 49 DOA and remained in hutches until 56 DOA. Calf starter and water were offered ad libitum. Ambient temperature and relative humidity in and outside the hutches were assessed hourly. Starter and MR intakes were recorded daily. Respiration rate and rectal temperature were determined 3 times each week. Body weight was measured at 3, 14, 28, 42, and 56 DOA. Plasma was collected at 5, 10, 14, 28, 42, 43, 45, 47, 49, 51, and 56 DOA for analysis of glucose, β-hydroxybutyrate, triglycerides, nonesterified fatty acids, urea nitrogen, and insulin concentrations. There were no treatment effects on starter intake, rectal temperature, or respiration rate. By 7 DOA, calves fed the IL and HL diets consumed the same amount of MR and a higher amount of MR than the CON calves. At wk 2, calves from all treatments had similar MR consumption before returning to the projected intake by design at wk 4. Calves fed the IL and HL treatments had similar body weight but were heavier than those fed the CON diet at wk 6, 7, and 8. Calves fed the IL and HL diets had similar average daily gain, which was higher than that of calves fed the CON diet. There was no difference in plasma metabolites among treatments, but insulin concentration increased as milk allowance increased. In summary, feeding an intermediate level of MR during summer improved calf growth compared with the CON diet, but a higher MR allowance did not support further improvements in calf performance.

Effect of different milk-removal strategies at weaning on feed intake and behavior of goat kids

Weaning from milk is stressful. We aimed to investigate the effect of three weaning strategies on feed intake and behavior of dairy goat kids. Forty-five, 3-month-old Saanen cross goats were allocated to one of three treatments: abrupt removal of milk (AB), gradual reduction of milk replacer in the same water volume (DILU), and gradual volume reduction (VOL). The goats on DILU and VOL were stepped down every 2 days over a 6-day period, whereas the goats on AB continued to receive baseline milk allowance. All treatments were weaned on day (d) 6. During step-down (d0-d2), the goats on DILU had lower (P < 0.05) average daily gains than the goats on AB and VOL. Treatment had no effect on milk refusals. The goats on DILU increased pellet intake earlier (d4-d5) than those on other treatments, eating twice as much as those on AB and VOL (P < 0.05); immediately after milk being no longer offered (d6-d7), the goats on VOL consumed less pellets than the goats on AB and DILU (P < 0.05). All goats consumed the same amount of pellet by d8-d9. Treatment did not affect vocalizations; after weaning (d6-d9), goats in all treatments continued to vocalize after pellet delivery (P = 0.003). The treatment had no effect on rumination or lying behavior; rumination increased goats in after weaning. In conclusion, dilution of milk replacer negatively affected weight gain initially; however, these goats consumed more pellets earlier. Gradual reduction of milk volume did not increase pellet intake, but weight gain was not negatively affected. Four days after weaning, no differences existed between the treatments, suggesting that any of the weaning strategies were suitable for 12-week-old goats.

An Economic Analysis of the Costs Associated with Pre-Weaning Management Strategies for Dairy Heifers.

Simple SummaryRearing of replacement female calves on a dairy farm is of critical importance to maintain herd sizes, improve the genetic quality of the herd, and remain economically sustainable. A 2-year investment period is needed for replacement female heifers to grow before entering the milking herd. The management of replacements over this 2-year period can vary greatly among operations, making it difficult to compare producers’ cost to benchmark. The objective of this project was to develop a model to calculate the cost of rearing a replacement heifer from birth to weaning under different housing, milk source, allotments, and labor and health management decisions to be used as a dairy farm decision support tool. We calculated the cost for management options with general cost values. We found that the average feed cost represented 46% of the total cost while labor, and fixed and variable costs represented 33%, 9%, and 12%, respectively. The total cost increased as milk allotment increased, but cost per Kg of gain decreased. The ranges in total cost within each management scenario often exceed the difference in cost from one scenario to the next. In conclusion, variable costs have the potential to vary among operations, playing a major role in the total cost of rearing replacements from birth to weaning.Dairy calves are raised in various housing and feeding environments on dairy farms around North America. The objective of this study was to develop a simulation model to calculate the cost of raising replacement dairy heifers using different inputs that reflect different management decisions and evaluate their influence on the total cost. In this simulation, 84 calves were modeled between 0–2 months of age to reflect a 1000 heifer herd. The decisions associated with housing, liquid diet source and allowance, labor utilization, and health were calculated. Costs and biological responses were reflective of published surveys, literature, and market conditions. A 10,000-iteration economic simulation was used for each management scenario using @Risk and PrecisionTree add-ons (Palisade Corporation, Ithaca, NY, USA) to account for variation in pre-weaning mortality rate, weaning age, and disease prevalence. As milk allotment increased, total feed cost increased. Feeding calves a higher allowance of milk resulted in a lower cost per kg of gain. Average feed cost percentage of the total cost was 46% (min, max: 33%, 59%) while labor, and fixed and variable cost represented 33% (20%, 45%), 9% (2%, 12%), and 12% (10%, 14%), respectively. Total pre-weaning costs ranged from $258.56 to $582.98 per calf across all management scenarios and milk allotments.