Effects of different planes of milk feeding and milk total solids concentration on growth,ruminal fermentation,health,and behavior of late weaned dairy calves during summer

Background:In recent years,there has been an increasing interest in using high quantities of milk or milk replacer(MR)in heat-stressed calves to alleviate the negative effects of high environmental temperatures on their performance.However,observations have indicated a decline in growth performance in the weaning and postweaning period,which might be optimized with increasing total solids(TS)in milk and weaning age.This study aims to optimize the effects of higher quantities of milk on late weaned calves'performance by increasing TS concentration or delivery route in summer conditions.Method:Forty-eight newborn Holstein calves were used in a 2×2 factorial arrangement with the factors of preweaning total plane of milk(PM)intake(low vs.high)and milk TS content(12%vs.17%).The treatments were(1)low PM(LPM)intake with 12%TS(TS intake=45.9 kg),(2)LPM intake with 17%TS(TS intake=65.1 kg),(3)high PM(HPM)intake with 12%TS(TS intake=63.7 kg);and(4)HPM intake with 17%TS(TS intake=90.3 kg).Calves were weaned at d 83,and the study was terminated at d 103 of age.Performance data(every 10 day),skeletal growth(d 80 and 100),ruminal fermentation parameters(d 48 and 91),and behavioral measurements(d 69,70,93 and 94)were analyzed as repeated measurements with PROC MIXED of SAS 9.4(SAS Institute Inc.,Cary,NC).Results:Calves receiving HPM consumed less PMR from d 44 to 83 of age,but they had higher ADG from d 24 to 53 of age compared to those fed LPM(PM×age,P<0.001).In addition,calves receiving milk with 17%TS had lower PMR intake from d 14 to 83 of age,but greater ADG from d 34 to 53 compared to those receiving milk with 12%TS(TS×age,P<0.001).Calves that received HPM had greater skeletal growth parameters compared to LPMfed calves,with a similar effect evident for calves fed milk with 17%TS compared with those fed milk with 12%TS.Calves receiving milk with 17%TS had greater fecal scores and diarrhea occurrence than those fed milk with 12%TS in HPM,but not LPM.Conclusions:Increasing PM and milk TS concentration improved growth in summer-exposed calves as demonstrated by increased pre-weaning ADG,pre-and post-weaning BW,and structural growth.

Colostrum Supplementation as an Aid for Improving Health and Growth Performance of Preweaned Holstein Dairy Calves

The adjective of this study was to determine the effect of partial replacement of whole milk with second- and third-milking colostrum on the health status and growth performance of preweaned Holstein dairy calves. A minimum of 110 calves of 2 - 3 days old Holstein Friesian calves were enrolled and randomly allocated to two treatment groups 1) CS—colostrum supplement group and 2) UC—unsupplemented control group. The CS group of calves received pooled second and third milking colostrum with Brix reading between 19 and 24% (mean 21.8% ± 1.75%) as colostrum supplement (one liter mixed with 3 L of whole milk), and UC group of calves received 4 L of whole milk in each of the 2 daily meals for 14 days. Serum IgG levels were determined to evaluate passive transfer of immunity. Milk and grain consumption was recorded for 28 days by research personnel. All calves were weighted at entry of the trial, at 28 days and at weaning (65 days). Calves receiving supplemental colostrum had less diarrhea and respiratory disease than control calves. Also, the results indicated that health problems were associated with low serum IgG levels and low-weight calves. Grain consumption and average daily gain (ADG) over 28 days of life were greater in CS group of calves compared with UC group of calves. Colostrum supplementation during the first 14 days of life in calves was effective in reading diarrheal and bovine respiratory diseases and in the use of antimicrobials. Further studies are needed to identify the molecular mechanisms involved in beneficial effects of colostrum supplementation on calf growth and health.

The age at first consumption of forage in calves and its effect on growth and rumination in the short‑and long‑term

Background Previous investigations into the effect of dietary forage on calf performance have been inconsistent,and there is a paucity of information exploring the effect of age on the growth performance and rumination of calves.Eighty-four female Holstein calves(41.5±4.2 kg)were enrolled at birth,a subset of the calves were fed calf starter only(CON,n=21)while the rest(n=63)were classified into three treatment groups:the early(EHAY,n=26,5.1±0.8 d),the middle(MHAY,n=21,7.9±0.8 d)and the late(LHAY,n=16,12.1±1.4 d)hay consumers.The short-term effect of the age at first forage consump-tion(AFF)on calves’feed intake was monitored until d 84.In addition,the long-term effects of AFF on body weight,structural growth and rumination behavior were recorded until d 196.Rumen samples were collected on d 1,7,35,84 and 196 to ana-lyze the rumen fermentation,while fecal samples were collected from d 78 to 84 to estimate digestibility parameters.Results Treatment had no effect on feed intake.While,the EHAY calves tended to have lower BW and ADG compared to LHAY and CON calves.Several total-tract apparent digestibility parameters and digestible nutrients intake were significantly lower in EHAY calves compared with CON and LHAY calves.Calves in the EHAY group tended to begin ruminating ealier,while CON calves were the latest(12.3 vs.15.5 days of age).A treatment and time interaction was present for rumination time due to greater rumination in calves consuming hay compared to CON calves in week 10 to 12,the differences in rumination disappeared afterwards,no long-lasting significant differences in the rumina-tion and rumen fermentation parameters were found between treatments.Conclusions In conclusion,this study showed that hay consumption earlier in life(in the first week,around 5 days of life)could negatively affect the growth of the calf in the short and long term.Compared to consuming hay from the second week(around 12 days of life)or feeding concentrate only without hay,starting to consume hay from the first week could compromise nutrient digestibility and digestible nutrient intake independent of developing rumination behaviour and rumen fermentation.

Effects of replacing steam-flaked corn with shredded sugar beet pulp on feed sorting, behavior, blood metabolites, and growth performance of dairy calves

This experiment was conducted to investigate the effects of partial replacement of steam-flaked corn(SFC)with shredded sugar beet pulp(SBP)in the starter diet on selective intake(sorting),feeding and chewing behavior,blood biochemical parameters,and growth in newborn female Holstein dairy calves.A total of 48 calves(3 d old;40.1±0.84 kg body weight;mean±SE)were randomly assigned to 1 of 2 feeding treatments containing 0 or 25%SBP(percentage of dry matter[DM])in the starter diet.Calves were weaned on d 61 and remained in the study until d 81.Intake of starter feed and total intake of DM(milk DM+starter feed DM),crude protein,and neutral detergent fiber were increased(P<0.05)by feeding SBP;however,intake of starch(P<0.01)and total intake of ether extract(P=0.03)were decreased with no apparent effect on total intake of ME.Average daily gain,feed efficiency,final weight,and skeletal growth also showed no significant changes.Circulating concentrations of glucose,total protein,and albumin were not affected by partial replacement of SBP with SFC;however,higher concentrations of blood urea-N(P=0.01)and a lower albumin-to-globulin ratio(P=0.03)were observed in SBP-vs.SFC-fed calves.Calves fed SBP sorted more for particles retained on the 4.75-mm sieve(P=0.02)and against particles retained on the 0.6-mm sieve and bottom pan(P<0.01).Intake of neutral detergent fibers and starch from particles retained on all sieve fractions was increased and decreased(P<0.01),respectively,by replacing SFC with SBP.Replacement of SBP with SFC was associated with increased meal length and meal size and increased rumination frequency and length,but decreased intervals between rumination(P≤0.01).Calves fed SBP spent more time eating,rumination,and standing and less time lying and non-nutritive oral behaviors(P<0.01).In general,25%replacement of SFC with SBP did not affect calf performance but increased time spent rumination and eating and decreased non-nutritive oral behaviors.

Supplementation with galacto-oligosaccharides in early life persistently facilitates the microbial colonization of the rumen and promotes growth of preweaning Holstein dairy calves

We aimed to determine the effects of dietary supplementation with galacto-oligosaccharides(GOS)on the growth performance,serum parameters,and the rumen microbial colonization and fermentation of pre-weaning dairy calves.The study comprised 2 phases of 28 and 42 d,respectively.During phase 1,24 newborn female Holstein dairy calves were randomly allocated to consume a diet supplemented with 10 g/d GOS(GOS,n=12)or not(CON,n=12).Thereafter,during phase 2,the GOS group was further divided into 2 groups:one that continued to consume GOS(GOSC,n=6)and one that no longer consumed GOS(GOSS,n=6),alongside the CON group.Galacto-oligosaccharides increased the average daily gain(ADG),body weight,feed efficiency,and serum high-density lipoprotein-cholesterol concentration of dairy calves during phase 1(P<0.05).Supplementation with GOS for the entire study reduced the incidence of diarrhea and increased the serum total protein and Ca concentrations(P<0.05)compared with the CON group.The effect of GOS supplementation persisted after it was stopped because the ADG and final body weight of the GOSS group were higher than those of the CON group(P<0.05).Furthermore,the GOSS group showed a persistently lower incidence of diarrhea and greater colonization of the rumen with probiotics,at the expense of less beneficial bacteria,which would promote ruminal fermentation and microbial protein synthesis.These findings provide a theoretical basis for the rational application of prebiotics and have important practical implications for the design of early life dietary interventions in dairy calf rearing.