Slide 1: The Weaning Transition in Dairy Calves: Why is it So Often So Traumatic?
The Weaning Transition in Dairy Calves: Why is it So Often So Traumatic? James K. Drackley Professor of Animal Sciences University of Illinois Urbana-Champaign, USA
Slide 2: Weaning: The "other" transition period
Weaning: The “other” transition period • Period preparing for and adapting to weaning • Critical stage of heifer’s life with many stressors
Slide 3: Changes around weaning
Changes around weaning • Diets – Removal of milk, total reliance on dry feed and free water, perhaps change from starter to grower • Environment – Moving to different pen • Social – Grouping with other calves – Removal of “surrogate mom” and suckling/milk feeding
Slide 4: Weaning distress compromises welfare
Weaning distress compromises welfare • Growth slumps – Attributable to lower nutrient intake and stress • Adverse behavioral stress – Vocalization, decreased resting • Increased disease susceptibility – Particularly respiratory and coccidiosis – Impaired immunity due to suboptimal nutrition and wean
Slide 5: Producers are feeding more milk
Producers are feeding more milk • NAHMS (2014) data showed US average amount fed was 5.7 L/d, which would be ~740 g/d (1.6 lb/d) of milk solids (Urie et al., 2018) • Contrasts with historical average of 1 to 1.25 lb solids/day • Many farms feeding 6 to >8 L/d
Slide 6: Death loss has declined over same period
Death loss has declined over same period • Deaths in preweaned heifers % of deaths declined from 11.0% of calves alive at 48 h of age in 1996 to 6.4% in 2014 • Related to greater milk intake early in life? Scours Respiratory Calving • Causes of death largely Joint/navel Unknown Injury Other known un
Slide 7: We are doing better with preweaned calves!
We are doing better with preweaned calves!
Slide 8: On average, fewer heifers die post-weaning
On average, fewer heifers die post-weaning • NAHMS (2014) data show mean mortality of 2.7% of heifers born alive
Slide 9: But, there are too many trainwrecks at weaning
But, there are too many trainwrecks at weaning • Three large dairies (12,000 to 20,000 cows) reported death losses around weaning of 20 to 30% of calves (M. E. Van Amburgh, personal communication 2023)
Slide 10: Post-weaning performance lags pre-weaning
Post-weaning performance lags pre-weaning Variable Holstein Jersey Birth weight, kg 43.0 35.1 Weaning weight, kg 91.4 70.1 ADG, kg/d 0.73 0.51 90-d weight, kg 104.0 86.2 ADG post-weaning, kg/d 0.60 0.76 Birth hip height, cm 82.8 75.8 Weaning hip height, cm 95.2 85.6 ADG height, cm/d 0.18 0.15 90-d h
Slide 11: Why do so many calves struggle at weaning?
Why do so many calves struggle at weaning? Photo courtesy of Jim Quigley
Slide 12: Mother Nature's feeding program
Mother Nature’s feeding program • Cows’ milk: 25 – 26% protein (dry solids basis) • Feeding rate: > 2x the “conventional” feeding rate of milk replacers (1 – 1.5 kg solids vs. ~ 0.5 kg), spread over 6 – 12 meals per day • First solid feed: High-quality fresh grass (high in sugars and easily fermente
Slide 13: Empty body weight as proportion of live weight decreases from before to after weaning
Empty body weight as proportion of live weight decreases from before to after weaning • Empty body weight (EBW) is body weight minus GI tract fill § Milk only: EBW = 0.94 live BW § Milk plus starter: EBW = 0.93 live BW § Weaned calf: EBW = 0.85 live BW So, gut fill is increasing during the weaning t
Slide 14: Impact of increasing gut fill on calf ADG postweaning
Impact of increasing gut fill on calf ADG postweaning Variable LMR + CCS HMR + CCS HMR + HCS SEM Overall ADG 5-10 wk, kg/d 0.89 0.83 0.92 0.12 5-wk digesta, kg 2.84 1.54 1.48 0.34 10-wk digesta, kg 10.29 9.54 11.32 0.94 ADG due to gut fill gain, kg/d 0.21 0.23 0.28 --- EBW gain 5-10 wk, kg/d 0.49 0.
Slide 15: The GI tract grows allometrically during the weaning transition
The GI tract grows allometrically during the weaning transition Variable LMR + CCS HMR + CCS HMR + HCS SEM Overall ADG 5-10 wk, kg/d 0.89 0.83 0.92 0.12 5-wk GIT, % of EBW 8.1 7.4 7.5 0.70 10-wk GIT, % of EBW 10.7 10.6 10.7 0.44 ADG due to GIT gain, kg/d 0.09 0.11 0.13 --- EBW gain 5-10 wk, kg/d 0.4
Slide 16: To avoid growth checks around weaning
To avoid growth checks around weaning: Must strive for starter intake and digestion pre-weaning
Slide 17: Pre-weaning starter intake determines post-weaning growth
Pre-weaning starter intake determines post-weaning growth 2 y = 0.0009x - 0.0244 R2 = 0.732 1.5 ADG weaning week, kg/d 1 0.5 0 0 200 400 600 800 1000 1200 1400 1600 1800 2000 -0.5 -1 -1.5 Preweaning starter DMI, g/d Stamey et al., 2012
Slide 18: Pre-weaning starter intake determines post-weaning growth
Pre-weaning starter intake determines post-weaning growth 2 y = 0.0009x - 0.0244 R2 = 0.732 1.5 0.875 kg/d ADG ADG weaning week, kg/d 1 0.5 0 0 200 400 600 800 1000 1200 1400 1600 1800 2000 -0.5 -1 1.0 kg/d starter intake -1.5 Preweaning starter DMI, g/d Stamey et al., 2012
Slide 19: Dry matter intake
Dry matter intake • Calves < 65 kg (Holstein) consume ~2.25% of BW as milk solids if fed ad libitum • Calves > 65 kg consume ~2.5% of BW as milk solids • Calves < 8 wk fed limited amounts of milk and ad libitum starter consumed 1.93 ± 0.33% of BW as total DM (219 treatment means from 64 studies) • W
Slide 20: Maintenance energy in weaned calves
Maintenance energy in weaned calves • NEm = 0.097 Mcal/kg EBW0.75 • Maintenance ME = 0.138 Mcal/kg EBW0.75 or 0.117 Mcal/kg BW0.75 • Greater than NRC (2001) but lower than in other systems and in Beef NASEM (2016) • For 85-kg calf, need about 1 kg/d of starter just for maintenance NASEM, 2021
Slide 21: Effects of environmental temperature on maintenance energy requirement
Effects of environmental temperature on maintenance energy requirement Increase in maintenance Increase in maintenance energy, kcal of NEm/d energy, % Temperature, °C (°F) < 3 wk old > 3 wk old < 3 wk old > 3 wk old 40 (104) 524 524 28 30 35 (95) 349 349 19 20 0 (32) 698 349 38 18 -10 (14) 1048 698
Slide 22: Prediction equations for starter intake
Prediction equations for starter intake • Equation developed for calves in temperate conditions: Starter DMI (g/d) = –652.525 + (BW × 14.734) + (MeiLD × 18.896) + (Fpstarter × 73.303) + (Fpstarter2 × 13.496) − (29.614 × Fpstarter × MEiLD) • RMSE of 262 g/d, CCC of 0.71 NASEM, 2021
Slide 23: Higher amounts of milk feeding result in lower starter DMI
Higher amounts of milk feeding result in lower starter DMI 3000 Predicted starter intake, g/d 2500 High milk intake Low milk intake 2000 To 1x feeding 1500 1000 500 Weaned 0 0 2 4 6 8 10 Week of life Calculated from NASEM, 2021
Slide 24: Starter intake drives rumen development
Starter intake drives rumen development
Slide 25: What are we trying to develop?
What are we trying to develop? • Size/volume of rumen (driven by feed) • Musculature of rumen (driven by bulk) • Absorptive epithelium (papillae; driven by VFA) • Microbial population (driven by feeds; produces VFA and depends on epithelium for acid absorption)
Slide 26: What are we trying to develop?
What are we trying to develop? • Size/volume of rumen (driven by feed) • Musculature of rumen (driven by bulk) • Absorptive epithelium (papillae; driven by VFA) • Microbial population (driven by feeds; produces VFA and depends on epithelium for acid absorption)
Slide 27: Effects of diet on rumen development
Effects of diet on rumen development • Milk and hay do little to develop rumen epithelium (papillae) • Starter grain (starch) or fresh grass (sugars) are key to development of rumen papillae via VFA production • Papillae development can occur by 3-4 wk of age with good starter management • Process t
Slide 28: Reticulum and rumen lining of 6-week-old calf fed milk only
Reticulum and rumen lining of 6-week-old calf fed milk only http://www.das.psu.edu/dairynutrition/calves/rumen/
Slide 29: Reticulum and rumen lining of 6-week-old calf fed milk and grain
Reticulum and rumen lining of 6-week-old calf fed milk and grain http://www.das.psu.edu/dairynutrition/calves/rumen/
Slide 30: Insufficient rumen development decreases nutrient digestibility after weaning
Insufficient rumen development (starter intake) before weaning decreases nutrient digestibility after weaning Milk feeding program Nutrient Low High Difference, % P Apparent digestibility, % DM 77.4 71.8 - 7.2 0.009 CP 77.1 71.6 - 7.1 0.01 NDF 34.7 20.3 - 41.5 0.02 Energy 75.6 69.8 - 7.7 0.007 Terré
Slide 31: ME obtained from solid feed is lower when rumen is under-developed
ME obtained from solid feed is lower when rumen is under-developed • Actual ME obtained from digestion may be lower than calculated value if rumen is not fully developed (Quigley et al., 2018, 2019) • Common in calves fed large amounts of milk • In NASEM (2021) users have option to use discounted (1
Slide 32: Approaching weaning…
Approaching weaning… • Tissue requirements for energy and amino acids do not change. • Efficiency of use of ME from VFA and milk endproducts is not greatly different. • Large differences in digestibility; ME of starter is ~ 60 to 70% of ME in milk replacer so growth will be ~2/3 of that on equal DM
Slide 33: Starter DMI required to support various rates of gain in weaned calves
Starter dry matter intake (DMI) required to support various rates of gain in weaned calves BW (kg) ADG (g/d) Starter required (kg/d) 60 600 1.68 60 800 1.96 80 600 1.95 80 800 2.24 Based on starter containing 3.16 Mcal ME/kg DM Calculated from NASEM, 2021
Slide 34: Starter DMI required to support various rates of gain in weaned calves
Starter dry matter intake (DMI) required to support various rates of gain in weaned calves BW (kg) ADG (g/d) Starter required (kg/d) 60 600of differences in Because 1.53 energy content of800 60 starter and its use by calves, 1.90 80 we need 1.4 600 to 1.7 times more 1.80 starter than milk replacer f
Slide 35: Factors contributing to poor weaning performance
Factors contributing to poor weaning performance • Weaning too early • Weaning from high amounts of milk not gradual enough • Too much forage • Poor starter quality or composition (too high in starch, poor palatability, particle size issues) • Poor water management • Stacking stressors at weaning
Slide 36: Factors contributing to poor weaning performance
Factors contributing to poor weaning performance • Weaning too early • Weaning from high amounts of milk not gradual enough • Too much forage • Poor starter quality or composition (too high in starch, poor palatability, particle size issues) • Poor water management • Stacking stressors at weaning
Slide 37: Higher rates of milk feeding decrease preweaning starter intake
Higher rates of milk feeding decrease preweaning starter intake Intensified Weaning Conventional Cowles et al., 2006
Slide 38: Weaning slump has been common with increased milk feeding
Weaning slump has been common with increased milk feeding Weaning Intensified Conventional Stamey et al., 2012
Slide 39: Daily starter intake around weaning
Daily starter intake around weaning 2000 Wean Con:Con Enh:Con Enh:Enh 1800 1600 To 1x feeding Starter DMI (g/d) 1400 1200 1000 800 22% CP starter 600 400 18% CP starter 200 0 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 Day Stamey et al., 2012
Slide 40: Weaning at 8 wk instead of 6 wk decreases the energy deficit at weaning
8 wk wean 6 wk wean Weaning at 8 wk instead of 6 wk decreases the energy deficit at weaning Eckert et al., 2015
Slide 41: Older age at weaning improves success
Older age at weaning improves success de Passilé et al., 2011
Slide 42: Factors contributing to poor weaning performance
Factors contributing to poor weaning performance • Weaning too early • Weaning from high amounts of milk not gradual enough • Too much forage • Poor starter quality or composition (too high in starch, poor palatability, particle size issues) • Poor water management • Stacking stressors at weaning
Slide 43: Slower weaning improves starter intake
Slower weaning improves starter intake Sweeney et al., 2010
Slide 44: Gradual weaning leads to sustained gains
Gradual weaning leads to sustained gains 3.5 MR intake (kg/d) 3.0 Starter intake (kg/d) ADG (kg/d) 2.5 Total intake (kg/d) 2.0 Intake, kg/d 1.5 1.0 0.5 0.0 0 2 4 6 8 10 Week of age Henrichs et al., 2021
Slide 45: Factors contributing to poor weaning performance
Factors contributing to poor weaning performance • Weaning too early • Weaning from high amounts of milk not gradual enough • Too much forage • Poor starter quality or composition (too high in starch, poor palatability, particle size issues) • Poor water management • Stacking stressors at weaning
Slide 46: Ad libitum forage can harm the weaning transition
Ad libitum forage can harm the weaning transition
Slide 47: Calves fed ad libitum hay and limited concentrate do not grow well
Calves fed ad libitum hay and limited concentrate do not grow well and are in poor health after weaning Photos courtesy of Jim Quigley
Slide 48: Rumen pH in young rumen is very low, with or without hay
Rumen pH in young rumen is very low, with or without hay in the diet Sustained rumen pH >6.0 is needed to establish functional populations of cellulose-digesting bacteria Quigley et al., 1992
Slide 49: Digestibility of NDF is very low in young calves
Digestibility of NDF is very low in young calves NDF Fatty acids Starter contained 25% alfalfa meal and 8% wheat bran. No forage fed. Spanski et al., 1996
Slide 50: Performance of calves fed varying amounts of grain and hay
Peformance of calves fed varying amounts of grain and hay Diet Variable 1 2 3 4 5 Grain DMI, kg/d 0.40 0.76 1.04 1.34 1.37 Hay DMI, kg/d 0.63 0.34 0.26 0.23 0.06 GIT contents, kg 13.8 12.8 12.8 11.9 11.3 ADG, kg/d 0.32 0.42 0.47 0.60 0.59 EBG, kg/d 0.14 0.24 0.31 0.43 0.43 % of ADG due to gut & fill
Slide 51: Postweaning performance of calves fed starter without or with chopped hay
Postweaning performance of calves fed starter without or with chopped hay Diet Trial and variable C G H1 H2 Trial 1 ADG, kg/d 0.91 0.74 1.22 1.02 Gain:Feed 0.52 0.42 0.66 0.58 Trial 2 ADG, kg/d 0.78 0.72 0.85 0.82 Gain:Feed 0.50 0.50 0.51 0.57 C = coarse starter, G = ground starter, H1 = C + 7.5% ch
Slide 52: Forage inclusion in starters increased DMI and body growth
Forage inclusion in starters increased DMI and body growth Variable CON AM10% AM20% CC SE Preweaning DMI, kg 9.9b 15.7a 14.5ab 9.5b 1.9 Postweaning DMI, kg 33.8b 38.1ab 42.3a 33.5b 1.9 Postweaning 0.47 0.44 0.49 0.44 0.05 gain:feed Digesta, kg 3.2b 3.7ab 4.7a 2.9b 0.3 Carcass-adjusted 25.7b 34.4a 35
Slide 53: Forage to concentrate ratio selected by calves given free choice of both
Forage to concentrate ratio selected by calves given free choice of both Forage F:C ADG (kg) None --- 0.72c Alfalfa hay 14:86 0.76bc Oat hay 8:92 0.93a Barley straw 5:95 0.88a Rye-grass hay 4:96 0.84ab Corn silage 5:95 0.82ab Conducted in Spain. Hay or straw chopped. Gain:feed was not different amon
Slide 54: Calves will choose high-quality alfalfa hay over starter concentrates
Calves will choose high-quality alfalfa hay over starter concentrates Photo by J. K. Drackley
Slide 55: Forage to concentrate ratio selected by calves given free choice of both
Forage to concentrate ratio selected by calves given free choice of both Forage F:C ADG (kg) None --- 0.72c For 1.5-kg Alfalfa hay total DM intake, 14:86forage intake 0.76bc would Oat haybe only 75 g/d for8:92 barley straw vs.a 0.93 210 g/dstraw Barley for alfalfa hay. 5:95 0.88a Rye-grass hay 4:96
Slide 56: Summary of forage recommendations
Summary of forage recommendations • Do not feed free choice alfalfa hay. – decreases starter intake, very palatable but low digestibility (high lignin) • Small amounts of chopped grass hays or straw (<100 g/d or 5% of total “TMR”) will increase starter consumption and feed efficiency. • Limit amount
Slide 57: A good solution
A good solution Photo by J. K. Drackley
Slide 58: Factors contributing to poor weaning performance
Factors contributing to poor weaning performance • Weaning too early • Weaning from high amounts of milk not gradual enough • Too much forage • Poor starter quality or composition (too high in starch, poor palatability, particle size issues) • Poor water management • Stacking stressors at weaning
Slide 59: Characteristics of starter formulation important for protein supply
Characteristics of starter formulation important for protein supply • Palatable ingredients • Sufficient fiber (>15% NDF, particle size) • Not dusty or too many fines • Protein for rumen and post-ruminal digestion; adequate total protein content • Avoid whole oilseeds and high fat content; corn bypr
Slide 60: Effects of starter physical form and forage
Effects of starter physical form and forage GS TS PS GS + AH Pazoki et al., 2017
Slide 61: Effects on rumen epithelium
Effects on rumen epithelium Pazoki et al., 2017
Slide 62: Digestible fiber and sugars vs. starch
Digestible fiber and sugars vs. starch • Typically starch content of starters has been 34 – 40% of DM • Recent concern has been that this contributes to very low rumen pH in transitioning calves (<5 for much of day) • Trend in industry is toward lower starch and higher digestible fiber and sugars –
Slide 63: Example of a low-starch, high sugar starter
Example of a low-starch, high sugar starter Ingredient % of DM Pellet Bypass soybean meal 19.78 Wheat midds 19.29 Canola meal 6.59 Dextrose 3.30 Dried whey 5.94 Blood meal 3.96 Rumen protected Met 0.73 Minerals, vitamins, additives 3.82 Flaked corn 20.11 Beet pulp shreds 13.19 Molasses 3.29 Molano e
Slide 64: Example of a low-starch, high sugar starter
Example of a low-starch, high sugar starter Chemical component % of DM CP 25.50 Crude fat 2.96 aNDFom 25.10 Starch 17.80 Sugars 14.10 Ash 8.18 ME, Mcal/kg 2.50 Molano et al., 2021
Slide 65: Factors contributing to poor weaning performance
Factors contributing to poor weaning performance • Weaning too early • Weaning from high amounts of milk not gradual enough • Too much forage • Poor starter quality or composition (too high in starch, poor palatability, particle size issues) • Poor water management • Stacking stressors at weaning
Slide 66: Water: the most important, and most neglected, nutrient
Water: the most important, and most neglected, nutrient
Slide 67: Milk-fed calves need free water
Milk-fed calves need free water • Milk or MR bypasses rumen, whether fed by nipple or bucket • Need supplemental water to enter rumen and support microbial environment • For 1 kg starter intake, need 4 L water intake • Inadequate water = less starter intake • = Decreased growth
Slide 68: Water and starter intake patterns are almost identical!
Water and starter intake patterns are almost identical! 4000 14 8 week wean 3500 12 Early - starter 3000 Late - starter Early - water 10 6 week wean 2500 Late - water g/d 8 2000 L/d 6 1500 4 1000 500 2 0 0 0 7 14 21 28 35 42 49 56 63 70 Age (Days) Courtesy M. Steele, University of Alberta Eckert et
Slide 69: Factors contributing to poor weaning performance
Factors contributing to poor weaning performance • Weaning too early • Weaning from high amounts of milk not gradual enough • Too much forage • Poor starter quality or composition (too high in starch, poor palatability, particle size issues) • Poor water management • Stacking stressors at weaning
Slide 70: Avoid "stacking" stressors at weaning
Avoid “stacking” stressors at weaning Vaccination • Do not move calves or change diet for 1 wk post- Dehorning weaning. Environmental stress • Do not combine weaning Social stress with other management tasks such as vaccination Nutritional stress and dehorning.
Slide 71: Summary
Summary To avoid traumatic weanings: • Don’t wean too early • Wean gradually • Don’t feed too much forage • Feed a high quality starter • Provide fresh water • Don’t stack stressors around weaning
Slide 72: Thank you!
Thank you! Thanks for your time! drackley@illinois.edu Questions?