Analysis of pre-weaning feeding policies and other risk factors influencing growth rates in calves on 11 commercial dairy farms

Abstract

Growth rates in pre-weaned calves influence their health, age at first calving and lifetime productivity. Many farms restrict milk rations to encourage solid feed intake and facilitate early weaning, but this can compromise growth. This study determined the milk feeding policies and associated growth rates on 11 commercial dairy farms in South East England, each following their normal management regime. Between 26 and 54 heifers were recruited per farm, providing a final cohort of 492, of which 71% were pure Holstein. Information on calf rearing practices (feeding, weaning, housing) and health was collected via questionnaires and weekly observations. Estimates of actual milk fed (kg solids) between 1 and 63 days were calculated for individual calves. Morphometric data (weight, height, length) were taken at weeks 1, 5 and 9 and at a median age of 7.5 months and growth rates were calculated. Most calves were fed milk replacer via automated feeders (four farms), teat feeder (one) or buckets (four) whereas two farms provided drums of acidified waste milk. Farms fed between 4 and 6 l/day of milk at mixing rates of 10% to 15%, providing 400 to 900 g/day of milk solids. Both skeletal growth rates and average daily weight gain (ADG) increased in the second month of life compared with the first: height growth from 0.17 ± 0.14 to 0.25 ± 0.16 cm/day and ADG from 0.48 ± 0.25 to 0.71 ± 0.28 kg/day. Post-weaning heifers up to 7.5 months had height increases of 0.16 ± 0.035 cm/day and ADG of 0.83 ± 0.16 kg/day. From 1 to 63 days 70% of calves had growth rates <0.7 kg/day and of these 19.6% gained <0.5 kg/day. Mean ADG before 9 weeks varied between farms from 0.52 ± 0.30 to 0.75 ± 0.20 kg/day. This was related to the amount of milk fed at both a farm and individual calf level. Increasing the total milk solids fed between 1 and 63 days from 20.4 to 46.3 kg (the 10 th to 90 th percentile observed) was associated with an increase of 0.11 kg/day ADG. All farms had a wide variation in growth rates despite single feeding policies. Higher circulating immunoglobulin G and IGF1 concentrations were associated with better growth, whereas low temperatures in month of birth, high scores for diarrhoea, respiratory and umbilical disease and large birth size reduced growth. Many commercially grown dairy heifers therefore experienced growth restriction in the pre-weaned period, potentially reducing their health, welfare and productivity.

Management factors associated with bovine respiratory disease in preweaned calves on California dairies: The BRD 100 study

“…We also observed a negative association of feeding a diet consisting of at least 90% saleable milk for at least 7 d at time of farm visit with BRD versus any other milk diet, including waste milk or milk replacer. Several studies have evaluated the effect of milk intake volume on calf performance (Jasper and Weary, 2002;Johnson et al, 2017). Studies evaluating the amounts of milk fed to calves on health outcomes have found mixed effects.…”

Linear body measurements and productivity of subtropicalHolstein–Friesiandairy calves

“…In order to reach future production targets, an average ADG of 0.70-0.80 kg/day for calves has been recommended. 8,35,36 The literature has previously been based on the US and European calf data and various growth rates have been cited in the literature ranging from 0.44 to 1.40 kg/day. 1,7,20 These growth rates varied depending on nutritional factors 7,27 and disease incidence.…”

“…11 A study by Johnson et al described how feeding policies and other risk factors impacted the growth rate on 492 UK calves. 36 The study reported that ADG varied between farms from 0.52 to 0.75 kg/day depending on how much milk was fed, the presence of for the fortnight prior to disease event, 1 level for the fortnight of the confirmed disease event, levels 2-4 are for the three fortnights (maximum number of fortnights until weaning assuming a calf was observed with an even on the first fortnight) after disease event fortnight. c Calves with diarrohea (n = 8) and soft faeces (n = 8) were included in the analysis.…”

Importance of Viral Disease in Dairy Cow Fertility

“…Numerous epidemiology studies in various countries around the world have determined that up to 46% of calves contract BRD [70,71]. For the calves that survive, there is mounting evidence of longer term consequences of juvenile disease on adult performance [72,73].…”

“…For the calves that survive, there is mounting evidence of longer term consequences of juvenile disease on adult performance [72,73]. BRD-affected animals have reduced growth rates [71,74], which in turn delay the age at first breeding and first calving. This is often associated with bronchopneumonic lesions and pleural adhesions [75].…”