Effects of a high milk intake during the pre‐weaning period on nutrient metabolism and growth rate in Japanese Black cattle

This study aimed to determine the effects of feeding an increased volume of high‐fat milk during the early post‐natal life on metabolite concentrations in the blood, the expression of key genes regulating intermediary metabolism in the skeletal muscles, and the rate of growth of Japanese Black cattle. All calves were fed a high‐fat milk replacer (crude protein, 26%; crude fat, 25.5%; total dissolved nitrogen, 116%). Control calves (n = 4) were nursed with 500 g milk replacer until 3 months of age, whereas calves in the experimental group (n = 4) were nursed with 1800 g milk replacer until 3 months, and then the volume was gradually reduced until 5 months. Body weight was significantly higher in the experimental group than in the control group at 7 months. Plasma glucose concentrations were significantly lower in the experimental group. Expression of glucose‐transporter‐4 messenger RNA (mRNA) was lower, whereas that of glucose transporter 1, cluster of differentiation 36, and carnitine palmitoyltransferase‐1b mRNA was significantly higher in the Longissimus thoracis of the experimental group. Nutritional status during early post‐natal life appears to strongly influence the growth rate and glucose and lipid metabolism in Japanese Black cattle.     

Effects at early stage of life of elevated milk replacer feeding on growth rate,plasma IGF‐I concentration and intestinal nutrient transporter expression in Holstein bull calves

In order to evaluate the effects of an elevated amount of modified milk replacer on body weight, daily gain, starter intake, plasma endocrine parameters and expression of nutrient transporters in small intestinal epithelia, Holstein bull calves (n = 24) were fed for 60 days either with the usual amount of 24% crude protein (CP) and 20% fat milk (CF) replacer (C group), or with a double amount of a modified milk replacer of 28% CP and 16% CF (E group). Body weight from D20 to D60 and daily gain before D40 was greater or tended to be greater for the E group than the C group. Plasma concentrations of insulin‐like growth factor‐1 (IGF‐I) and insulin were greater for the E group than the C group on D28 but not on D56, without changing plasma growth hormone levels. Gene expression for sodium‐dependent glucose transporter 1 and fatty acid translocase (CD36) was altered in day‐ and intestine‐dependent manners. From these findings, we conclude that an elevated intake of milk replacer given up to 40 days old is sufficient to enhance body weight, which may be associated with increased plasma IGF‐I concentrations, in Holstein bulls.     

Insulin resistance selectively alters cell-surface glucose transporters but not their total protein expression in equine skeletal muscle

Background: Insulin resistance (IR) has been widely recognized in humans, and more recently in horses, but its underlying mechanisms are still not well understood. The translocation of glucose transporter 4 (GLUT4) to the cell surface is the limiting step for glucose uptake in insulin‐sensitive tissues. Although the downstream signaling pathways regulating GLUT translocation are not well defined, AS160 recently has emerged as a potential key component. In addition, the role of GLUT12, one of the most recently identified insulin‐sensitive GLUTs, during IR is unknown. Hypothesis/Objectives: We hypothesized that cell‐surface GLUT will be decreased in muscle by an AS160‐dependent pathway in horses with IR. Animals: Insulin‐sensitive (IS) or IR mares (n = 5/group). Methods: Muscle biopsies were performed in mares classified as IS or IR based on results of an insulin‐modified frequently sampled IV glucose tolerance test. By an exofacial bis‐mannose photolabeled method, we specifically quantified active cell‐surface GLUT4 and GLUT12 transporters. Total GLUT4 and GLUT12 and AS160 protein expression were measured by Western blots. Results: IR decreased basal cell‐surface GLUT4 expression (P= .027), but not GLUT12, by an AS160‐independent pathway, without affecting total GLUT4 and GLUT12 content. Cell‐surface GLUT4 was not further enhanced by insulin stimulation in either group. Conclusions and Clinical Importance: IR induced defects in the skeletal muscle glucose transport pathway by decreasing active cell‐surface GLUT4.     

Importance of milk replacer intake and composition in rearing orphan foals

Effects of milk replacer composition and intake on the growth of orphan foals were evaluated. Twenty foals were assigned to four treatments: 1) mare-nursed, 2) commercial foal milk replacer at recommended intakes (standard), 3) commercial foal milk replacer at high intakes (high), and 4) acidified replacer at recommended intakes (acidified). Foals fed milk replacer diets were weaned at 12-24 hours postpartum and fed milk replacer for 50 days. Mare-nursed foals were weaned between 52 and 56 days of age. Foals fed replacer diets gained 12% to 28% less weight than mare-nursed foals up to two weeks of age. However, by four months of age, weights of replacer-fed foals were similar to those of mare-nursed foals and 32 other mare-nursed foals at the farm weaned between three and four months postparium. Foals drank 10 to 12 L/100 kg body weight (BW) in fluid replacer daily over the trial period. During the first week, high intake foals consumed 26% more replacer (p<0.05) than foals fed acidified or standard diets. This higher intake resulted in diarrhea earlier (6-11 days vs 11-22 days) and for a longer time (6.3 days vs 2.5-3.6 days) than in foals fed recommended amounts. Mare-nursed foals developed “foal heat scours” in the second week postpartum. After the first week, foals fed high replacer diet voluntarily consumed the same volume of fluid replacer as foals fed the standard intake. Foals ate less than 1 kg grain mix/100 kg BW daily to one month of age, then increased intake to 1.5-2 kg/ 100 kg BW to weaning. Water intake was 20-40% of daily fluid intake and was correlated (r = 0.85) to dry matter intake. Foals in the high intake group ate less (p<0.05) solid feed and drank less water than foals fed the standard and acidified diets. The foal's stomach capacity appears to limit meal size and thus replacer intake. If recommended feeding intervals are used, replacer intakes by foals are less than 15% BW daily. High volume intakes appeared to prolong diarrhea. Normal growth rates occur when replacer and good-quality feeds are fed concurrently.     

Glucose transport in the equine hoof

Reasons for performing study: Several conditions associated with laminitis in horses are also associated with insulin resistance, which represents the failure of glucose uptake via the insulin‐responsive glucose transport proteins in certain tissues. Glucose starvation is a possible mechanism of laminitis, but glucose uptake mechanisms in the hoof are not well understood. Objectives: To determine whether glucose uptake in equine lamellae is dependent on insulin, to characterise the glucose transport mechanism in lamellae from healthy horses and ponies, and to compare this with ponies with laminitis. Methods: Study 1 investigated the effects of insulin (300 µU/ml; acute and 24 h) and various concentrations of glucose up to 24 mmol/l, on 2‐deoxy‐D‐[2,6‐³H]glucose uptake in hoof lamellar explants in vitro. Study 2 measured the mRNA expression of GLUT1 and GLUT4 transport proteins by PCR analysis in coronary band and lamellar tissue from healthy horses and ponies, ponies with insulin‐induced laminitis, and ponies suffering from chronic laminitis as a result of equine Cushing's syndrome. Results: Glucose uptake was not affected by insulin. Furthermore, the relationship between glucose concentration and glucose uptake was consistent with an insulin‐independent glucose transport system. GLUT1 mRNA expression was strong in brain, coronary band and lamellar tissue, but was weak in skeletal muscle. Expression of GLUT4 mRNA was strong in skeletal muscle, but was either absent or barely detectable in coronary band and lamellar tissue. Conclusions: The results do not support a glucose deprivation model for laminitis, in which glucose uptake in the hoof is impaired by reduced insulin sensitivity. Hoof lamellae rely on a GLUT1‐mediated glucose transport system, and it is unlikely that GLUT4 proteins play a substantial role in this tissue. Potential relevance: Laminitis associated with insulin resistance is unlikely to be due to impaired glucose uptake and subsequent glucose deprivation in lamellae.     

脂肪水平对早期断奶犊牛生长性能及血清生化指标的影响

早期断奶犊牛饲喂不同脂肪含量代乳品,研究脂肪水平对犊牛生长性能、血清生化指标及饲料进食量的影响,为犊牛生长规律和脂肪需要提供科学依据,为实际生产中犊牛早期断奶和培育提供技术指导。试验选取12头新生荷斯坦公犊牛,分为EE9、EE13、EE17 3组,每组４头,分别饲喂蛋白质水平相同、脂肪含量为9%、13%及17%的3种代乳品。每日记录犊牛开食料的采食情况,并于犊牛10、20、30、40、50、60日龄清晨空腹测定犊牛体重及体尺指标,同时采集犊牛的血液样本进行分析。研究结果表明,3组犊牛哺乳期的饲料日进食量分别为706.9、666.9、569.3 g;10~60日龄的平均日增重分别为498、544、488 g,EE13组犊牛日增重高于EE9、EE17组的犊牛;犊牛60日龄时,EE13组犊牛的体高、体斜长及管围均高于其它2组。血清尿素氮、血糖、甘油三酯的水平不受代乳品脂肪含量的影响,但日龄对哺乳期犊牛甘油三酯含量的影响差异显著(P<0.05)。随日龄的增加,犊牛的生长速度和饲料的进食量逐渐增加,低脂肪的代乳品(EE9)不能满足犊牛的能量需要,高脂肪的代乳品（EE17）抑制了犊牛对开食料的采食量,饲喂脂肪含量13％的代乳品（EE13）对犊牛生长发育优于其它2组。脂肪含量对犊牛血清生化指标的影响不显著。     

Effects of feeding level of milk replacer on body growth,plasma metabolite and insulin concentrations,and visceral organ growth of suckling calves

The objective was to evaluate effects of feeding level of milk replacer on body growth, plasma metabolite and insulin concentrations, and allometric growth of visceral organs in suckling calves. Holstein bull calves (n = 8; 3–4 days of age) were fed either a low amount (average 0.63 kgDM/day, LM) or high amount (average 1.15 kgDM/day, HM) of high protein milk replacer until they were slaughtered at 6 weeks of age. Body weight (BW) at 4, 5, and 6 weeks of age, feed intake, average daily gain, and feed efficiency were higher in the HM than LM calves. The HM group had higher plasma glucose at 3 and 4 weeks of age and insulin levels after the age of 4 weeks compared with LM calves whereas no effect was detected on plasma nonesterified fatty acid or urea nitrogen concentrations. The HM calves had greater empty body weight (EBW), viscera‐free BW and most of the organs dissected than LM calves. Relative weights (% of EBW) of liver, spleen, kidneys, and internal fat were higher, whereas head and large intestine was lower in HM than LM calves. The results suggest that increased milk feeding levels would accelerate the growth of the body and specific organs.     

Adverse effects of a 10‐day course of ibuprofen in Holstein calves

Nonsteroidal anti‐inflammatory drugs (NSAIDs) are recommended for various conditions in cattle. Ibuprofen is an inexpensive short‐acting NSAID and is readily available in liquid formulation for administration to bottle‐fed calves. We compared the adverse effects of a 10‐day course of ibuprofen and placebo in 16 five‐ to six‐week‐old Holstein bull calves that were being treated for experimentally induced bovine respiratory syncytial virus infection. Ibuprofen was administered as a liquid in milk replacer at 30 mg/kg divided three times daily. We found an increased prevalence of abomasal ulceration 5 of 8 in the ibuprofen compared to placebo group 2 of 6 (P = NS). There was one (1 of 8) case of mild interstitial nephritis in the ibuprofen and none (0 of 8) in the placebo group (P = NS). Renal function as measured by serum BUN and creatinine levels was not different between groups; no animal demonstrated an increase in creatinine.     

Glucose and insulin metabolism in ruminating and veal calves fed high and low fat diets.

Holstein male calves were maintained on conventional (milk to 6 wk of age, fed grain and hay after weaning) and veal (milk replacer only) diets to 16 wk of age. Within each of these 2 physiological states (ruminating or non-ruminating), calves were fed low or high fat diets (ruminating: 3 and 10%; veal: 10 and 18%). Glucose tolerance tests were undertaken at 8 and 16 wk of age in each group. Basal concentrations (4 hr postfeeding) and areas under the response curves for plasma glucose and insulin were higher in veal calves (P < .0001). Ruminating calves fed higher fat utilized glucose more readily (smaller areas under the curves for both glucose and insulin, P < .10) than those fed lower fat. Age did not influence basal glucose concentrations (P > .10), but older calves had higher basal insulin (P < .0001) and greater areas under the curves (P < .0005) for both glucose and insulin after a glucose challenge. Rate of clearance (k) was greater in ruminating calves (P < .001). Though rate of clearance in veal calves was slower, larger plasma pool size caused veal calves on average to utilize glucose at a 15% greater rate per kg body weight than ruminating calves. Whereas fat concentration in the diets did not influence glucose metabolism in veal calves, the high lactose content (> 50% of diet dry matter) of veal diets induced severe insulin resistance in these calves.     

Effect of sorghum grain supplementation on glucose metabolism in cattle and sheep fed temperate pasture

The aim of this work was to evaluate the effect of sorghum grain supplementation on plasma glucose, insulin and glucagon concentrations, and hepatic mRNA concentrations of insulin receptor (INSR), pyruvate carboxylase (PC), and phosphoenolpyruvate carboxykinase (PCK1) mRNA and their association with nutrient intake, digestion and rumen volatile fatty acids (VFA) in cattle and sheep fed a fresh temperate pasture. Twelve Hereford × Aberdeen Angus heifers and 12 Corriedale × Milchschaf wethers in positive energy balance were assigned within each species to one of two treatments (n = 6 per treatment within specie): non‐supplemented or supplemented with sorghum grain at 15 g/kg of their body weight (BW). Supplemented cattle had greater plasma glucose concentrations, decreased plasma glucagon concentrations and tended to have greater plasma insulin and insulin‐to‐glucagon ratio than non‐supplemented ones. Hepatic expression of INSR and PC mRNA did not differ between treatments but PCK1 mRNA was less in supplemented than non‐supplemented cattle. Supplemented sheep tended to have greater plasma glucagon concentrations than non‐supplemented ones. Plasma glucose, insulin, insulin‐to‐glucagon ratio, and hepatic expression of INSR and PC mRNA did not differ between treatments, but PCK1 mRNA was less in supplemented than non‐supplemented sheep. The inclusion of sorghum grain in the diet decreased PCK1 mRNA but did not affect PC mRNA in both species; these effects were associated with changes in glucose and endocrine profiles in cattle but not in sheep. Results would suggest that sorghum grain supplementation of animals in positive energy balance (cattle and sheep) fed a fresh temperate pasture would modify hepatic metabolism to prioritize the use of propionate as a gluconeogenic precursor.     

A 90‐day adaptation to a high glycaemic diet alters postprandial lipid metabolism in non‐obese horses without affecting peripheral insulin sensitivity

High glycaemic feeds are associated with the development of insulin resistance in horses. However, studies that evaluated the effect of high glycaemic feeds used horses that either ranged in body condition from lean to obese or were fed to increase body condition over a period of months; thus, the ability of high glycaemic feeds to induce insulin resistance in lean horses has not been determined. This study evaluated the insulin sensitivity of 18 lean horses fed a 10% (LO; n = 6), 20% (MED; n = 6) or 60% (HI; n = 6) non‐structural carbohydrate complementary feed for 90 days. Although both the MED and HI diets increased insulinaemic responses to concentrate feeding in relation to the LO diet (p > 0.05), neither induced insulin resistance, as assessed by glucose tolerance test, following the 90‐day feeding trial. Interestingly, the post‐feeding suppression of plasma non‐esterified fatty acids was less pronounced in HI‐fed horses (p = 0.054) on days 30 and 90 of the study, potentially indicating that insulin‐induced suppression of adipose tissue lipolysis was reduced. As insulin‐resistant animals often have elevated plasma lipid concentrations, it is possible that altered lipid metabolism is an early event in the development of insulin resistance. The effects of high glycaemic feeds that are fed for a longer duration of time, on glucose and lipid metabolism, should be investigated further.     

Effect of Supplementary Feeding Milk Replacer on Growth Performance,Nutrient Digestibility,Serum Biochemistry Indexes in Piglets during Lactation

This experiment was conducted to study the effect of supplementary feeding milk replacer on growth performance,nutrient digestibility,serum biochemistry indexes in piglets during lactation,and explore the feasibility of shorten the weaning age of piglets by feeding milk replacer. One hundred and twenty (twelve litters) 5 days old piglets with average body weight of (3.12±0.63)kg were assigned into two groups with sixty piglets per group (six litters)and one litter of piglets per replicate. The piglets in control group received supplementary creep feed and were weaned on 28 days old,whereas the piglets in experimental group received supplementary creep feed and milk replacer (creep feed:milk replacer=1:1) and were weaned on 21 days old. The piglets in experimental group were continued feeding with creep feed and milk replacer until 28 days old. All piglets were fed with same diets from 28 to 70 days old. The results showed as follows:① Comparing with control group,the body weight of piglets in experimental group were not significantly changed at 5,21,28 and 70 days old (P>0.05),ADFI and F/G were extremely significantly or significantly increased during 5 to 21 days old,22 to 28 days old and 5 to 28 days old (P < 0.01;P < 0.05),while ADG was extremely significantly decreased during 22 to 28 days old compared with control group (P<0.01).② The digestibility of GE,DM,OM and EE of experimental group were significant higher than control group (P<0.05).③ All serum biochemistry indexes between the two groups had no significant differences (P>0.05). In conclusion,supplementary milk replacer feeding could increase the feed intake and dietary digestibility of weaned piglets. The age of wean could be forward to 21 days old according to the final body weight of weaned piglets when fed milk replacer supplementation.     

The effects of diet and age on serum complement system activity in goat kids

Thirty new born male kids were allotted into three groups to evaluate the effects of diet and age on complement system activity in serum. After the colostrum feeding period, the control group (C) received a commercial milk replacer; the CLA group received 20 g/kg milk replacer DM of conjugated linoleic acid; and the GMK group was fed with goat milk. The kids were fed colostrum for 2 days and then either milk replacer or goat milk from days 3 to 60. Blood samples were taken at 1, 10, 20, 30, 40, 50 and 60 days of age. The complement system activity was higher (P < 0.05) in the GMK group throughout the whole experiment through alternative pathway. C kids did not present complement activity at any time. CLA group complement activity was statistically higher than that of C kids from 30 to 60 days, through alternative pathways. In conclusion, the milk replacer formula should be reformulated because it did not induce any complement system activity in the first two months of life.     

Effects of two different rearing protocols for Holstein bull calves in the first 3 weeks of life on health status,metabolism and subsequent performance

The aim of this study was to investigate the impact of weight gain of calves within the first 3 weeks of life on health status and subsequent performance. Holstein bull calves were reared either intensively (IR; individual hutches and ad libitum milk feeding for the first 3 weeks of life; n = 24), or according to the established protocol [ER; 4 l milk/day in hutches during week 1 and 720 g/day milk replacer (MR) from day 8 to 21 in a group pen; n = 24]. Water, hay and concentrates were freely available to all calves. From week 4, calves of both groups were housed together in a group pen and fed 720 g MR/day; step‐down weaning was performed between week 5 and 10. Key metabolic blood parameters were analysed on day 2, 12, 21 and 70 of life. After weaning, all animals were fed concentrates and corn silage until slaughter at an age of 8 months. Within the first 3 weeks, average daily weight gain was threefold higher in IR calves in relation to ER calves (1.28 vs. 0.38 kg/day, p < 0.001). Neither incidence nor duration of scouring differed significantly between groups. Starter intake (week 4–10) was higher in IR calves in relation to ER calves (49.7 vs. 38.0 kg/calf, p = 0.006). Serum glucose, urea, albumin and insulin were higher at an age of 21 days in IR calves in relation to ER calves; no differences were obvious at an age of 70 days. Plasma GH and IGF‐I concentrations revealed an uncoupling of the somatotropic axis in ER calves within the first 3 weeks of life. At slaughter, body weight of IR calves tended to be higher than that of the ER calves (320 vs. 309 kg, p = 0.07). In conclusion, intensive feeding and individual housing during the first 3 weeks of life had positive long‐term effects on subsequent performance.     

Basal levels and responses to glucose infusion of plasma glucose and insulin in beef steer before and after the end of the growing phase on pasture

We examined the effect of grazing during the growing phase on plasma glucose and insulin behavior at the end of the growing phase and at the early stage of the subsequent fattening phase in beef steers. From 13 to 45 weeks of age (growing phase), crossbred beef steers were grazed with minimal supplement (group G: n = 5) or housed while being fed on hay and concentrate (group H: n = 5). Following this phase, both groups were housed for finishing (fattening phase). At the end of the growing phase, group G showed faster plasma glucose disappearance after intravenous glucose infusion, with a smaller plasma insulin response, compared with group H. At the third week of the fattening phase, group G still showed higher glucose tolerance, although they experienced abrupt changes in nutritional and environmental factors. The results suggest that grazing during the growing phase probably improves the glucose tolerance and insulin response to glucose infusion in steers compared with animals that were housed during the corresponding period, and the improved properties may persist at least a few weeks after the commencement of fattening.     

哺乳期补饲代乳品对仔猪生长性能、营养物质消化率及血清生化指标的影响

试验旨在研究哺乳期补饲代乳品对仔猪生长性能、营养物质消化率及血清生化指标的影响,并探讨代乳品对缩短仔猪断奶日龄的可行性。选用120头（12窝）5日龄、平均体重（3.12±0.63）kg的仔猪,随机分为两组,每组60头（6窝,每窝为1个重复）。对照组补饲教槽料至28日龄断奶;试验组补饲代乳品和教槽料（代乳品：教槽料=1：1）至21日龄断奶,断奶后继续饲喂代乳品和教槽料至28日龄;28日龄后试验组和对照组饲喂相同日粮至70日龄。结果显示：①整个试验期,两组仔猪在5、21、28和70日龄时体重差异均不显著（P>0.05）;在5~21、22~28和5~28日龄阶段,试验组仔猪平均日采食量（ADFI）和料重比（F/G）均极显著或显著高于对照组（P < 0.01;P < 0.05）;而在22~28日龄阶段,试验组平均日增重（ADG）极显著低于对照组（P<0.01）。②试验组仔猪保育期的日粮总能（GE）、干物质（DM）、有机物（OM）和粗脂肪（EE）的消化率均显著高于对照组（P<0.05）。③在70日龄时,两组仔猪各项血清生化指标均无显著差异（P>0.05）。结果提示,补饲代乳品可显著增加哺乳期仔猪的采食量,同时促进保育期仔猪对日粮中营养物质的消化吸收。从保育期末体重来看,哺乳期补饲代乳品的仔猪提前至21日龄断奶是可行的。     

Sheep rumen metabolic development in response to age and dietary treatments

This study examined the time course of rumen metabolic development in the absence of solid feed consumption and the effect of delayed solid feed consumption on sheep rumen development. Twenty-seven lambs consumed milk replacer until slaughter at nine ages from 1 to 84 d (milk group). Three additional lambs consumed milk replacer from 1 to 48 d. From 49 d until slaughter at 84 d, these lambs were weaned onto solid feed (fed group). At slaughter, rumen contents were removed for VFA analysis and rumen epithelium was preserved for morphological examination. Rumen epithelial cells were isolated and incubated in media containing 2.5 mM U-[14C]-glucose or 10 mM 1-[14C]-butyrate. Rumen VFA concentrations did not change with age in lambs given milk replacer. At 84 d of age, intraruminal VFA concentrations were elevated in lambs consuming solid feed compared to 84-d-old lambs given milk replacer (P < .05). The number of ruminal papillae per square centimeter decreased (P < .05) while papillae length and width did not change significantly with age in rumen epithelium from lambs given milk replacer. At 84 d of age, rumen epithelium from lambs in the fed group had fewer and larger papillae/per square centimeter than rumen epithelium from lambs given milk replacer (P < .05). Rates of glucose and butyrate oxidation and acetoacetate and lactate production by rumen cells isolated from lambs given milk replacer did not change with age. Beta-hydroxybutyrate (BHBA) production was undetectable before 42 d of age in lambs given milk replacer and increased to levels found in conventionally raised adults by 84 d. At 84 d there were no differences in rates of glucose and butyrate oxidation or acetoacetate and lactate production by rumen cells between the two treatment groups. Thus, the change in substrate oxidation from glucose to butyrate, indicative of rumen metabolic maturation, does not occur in the absence of solid feed consumption. However, the development of rumen ketogenesis, as evidenced by increased BHBA production, does occur in the absence of solid feed consumption. Delaying the initiation of solid feed consumption results in rumen morphological development but does not stimulate rumen metabolic development. Increased intraruminal VFA concentrations, earlier exposure to VFA, or a longer period of exposure to VFA may be required to induce the genes responsible for rumen metabolic development.     

Levels of insulin and glucose in calves during the first 6 months of life]

Twenty-four calves of the Holstein-Friesian breed were included into a trial. The trial was performed from April (when the calves were born) to October. The objective of the study was to investigate variations in insulin and glucose levels over a longer time period of the postnatal development of calves. The blood was sampled by the jugular vein puncture at the age of 1, 2, 3, 5, 14, 21, 28, 35, 49, 63, 91, 118, 147 and 175 days. The calves were housed in a prophylactorium calf-house till the age of 21 days: till the age of 14 days they were housed individually and then in groups of 2-3 calves in a small pen. The calves were fed milk till the age of 26 or 28 days, after a fortnight the feed intake was increased from the previous 3 litres to 5-6 litres per head/day. At the age of 21 days the calves were transferred to pens in the calving room. At the age of 26 days twelve calves were transferred to a barn for young cattle rearing, the remaining twelve calves were transferred at the age of 28 days; here they were housed by 10-12 head per pen and they were fed a commercial milk replacer diluted at a 1:10 ratio, the feed intake being 6-8 litres a day, and a commercial pelleted calf starter TKS at the amount of 1.0-1.1 kg.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of butyrate supplementation in antibiotic‐free milk replacer and starter on growth performance in suckling calves

The aim of this study was to evaluate butyrate supplementation of antibiotic‐free milk replacer and starter on growth performance in male Holstein calves. Twenty‐nine calves were divided into two groups. Group C (n = 13) was fed antibiotic‐free milk replacer without supplementation, and Group B (n = 16) was fed antibiotic‐free milk replacer supplemented with butyrate (1.6 % DM of Gustor BP70^®). Starter in Group B contained 0.3 % DM of Gustor BP70^®. The intake of milk replacer was lower in group B than in C (p = 0.07 for the treatment x week interaction). Body weight (BW) and heart girth (HG) in group B was higher than in C during the experimental period (p = 0.07 and 0.01 for the treatment × week interaction, respectively). The duration of the weaning period in group B was shorter than in group C (p = 0.02). β‐hydroxybutyrate (BHBA) was higher in group B than in C (p = 0.04). Insulin like growth factor‐1 (IGF‐1) concentrations tended to be higher in group B than in C (p = 0.07 for treatment × week interaction). Our results show that butyrate supplementation in antibiotic‐free milk replacer and starter exerted positive effects on growth performance in suckling calves.