Plasma concentrations of glucagon-like peptide 1 and 2 in calves fed calf starters containing lactose

The objective of this study was to evaluate the effects of lactose inclusion in calf starters on plasma glucagon-like peptide (GLP)-1 and GLP-2 concentrations and gastrointestinal tract development in calves. Holstein bull calves (n = 45) were raised on an intensified nursing program using milk replacer containing 28.0% CP and 15.0% fat, and were fed a texturized calf starter containing 0 (control), 5.0 (LAC5), or 10.0% (LAC10; n = 15 for each treatment) lactose on a DM basis. Lactose was included in the starter by partially replacing dry ground corn in pelleted portion of the starter. All calf starters were formulated with 23.1% CP. The ethanol-soluble carbohydrate concentrations of the control, LAC5, and LAC10 starters were 7.3, 12.3, and 16.8% on a DM basis, respectively. Starch concentrations of the control, LAC5, and LAC10 starters were 29.7, 27.0, and 21.4% on a DM basis, respectively. All calves were fed treatment calf starters ad libitum. Blood samples were obtained weekly from 1 to 11 wk of age, and used to measure plasma GLP-1, GLP-2, and insulin concentrations, serum β-hydroxybutyrate (BHB) concentration, and blood glucose concentration. At 80 d of age, calves were euthanized, and weights of the reticulorumen, omasum, abomasum, small intestine, and large intestine tissue were measured. Serum BHB concentration was higher for calves fed the LAC10 (171 μmol/L) starter than for those fed the control (151 μmol/L) and LAC5 (145 μmol/L) starters. Plasma GLP-1 and GLP-2 concentrations did not differ between treatments. However, relative to the baseline (1 wk of age), the plasma GLP-1 concentration was higher for the LAC10 (125.9%) than for the LAC5 (68.2%) and control (36.8%), and for the LAC5 than for the control (36.8%). Moreover, similar differences between treatments were observed for GLP-2 concentration relative to the baseline (88.2, 76.9, and 74.9% for LAC10, LAC5, and control treatments, respectively). The serum BHB concentration was positively correlated with the plasma GLP-1 concentration (r = 0.428). Furthermore, the plasma GLP-1 concentration was positively correlated with the insulin concentration (r = 0.793). The weights of the reticulorumen, omasum, abomasum, small intestine, and large intestine were not affected by the treatments. In conclusion, inclusion of lactose in calf starters resulted in higher plasma GLP-1 and GLP-2 concentrations, and BHB might be associated with higher plasma GLP-1 concentration.     

The effect of tube versus bottle feeding colostrum on immunoglobulin G absorption,abomasal emptying,and plasma hormone concentrations in newborn calves

The objective of this study was to determine if feeding colostrum to newborn calves through an esophageal tube, compared with a nipple bottle, would delay abomasal emptying, which would in turn decrease passive transfer of IgG and plasma glucose, insulin, and glucagon-like peptide (GLP) 1 and GLP-2 concentrations. Twenty newborn Holstein bull calves were fed 3 L of colostrum replacer (200 g of IgG) through either an esophageal tube or nipple bottle at 2 h after birth followed by feeding pooled whole milk every 12 h after birth. Acetaminophen was mixed into the colostrum meal as a marker for abomasal emptying. A jugular catheter was inserted 1 h after birth and blood was sampled frequently to analyze serum for IgG and acetaminophen and plasma for glucose, insulin, GLP-1, and GLP-2. Feeding method did not affect abomasal emptying, and as a result no treatment effect was present on serum IgG concentrations. Maximum concentration of serum IgG was 24.4 ± 0.40 mg/mL (± standard error), which was reached at 14.6 ± 1.88 h after the colostrum meal for both groups. Apparent efficiency of absorption at maximum concentration of IgG was 52.9%, indicating high efficiency of passive transfer of IgG for both treatments. Tube feeding increased glucose and insulin area under the curve before the first milk meal, most likely due to the decreased time to consume the colostrum meal. In addition, tube-fed calves consumed 0.5 ± 0.13 L more milk in their first milk meal than bottle-fed calves. No treatment effect on plasma concentrations of GLP-1 or GLP-2 was present, but both hormones increased after colostrum feeding. These findings confirm that there is no effect on absorption of IgG from colostrum when feeding good-quality colostrum at a volume of 3 L through either an esophageal tube or nipple bottle.     

Short communication: The effects of offering a high or low plane of milk preweaning on insulin-like growth factor and insulin-like growth factor binding proteins in dairy heifer calves

Although positive effects on growth have been shown when calves are placed on high planes of nutrition, little information exists regarding the effect of this feeding strategy on insulin-like growth factor-1 (IGF-1), a hormone whose fundamental action is to stimulate growth, and its binding proteins during the preweaning period. The objective of this study was to characterize IGF-1 and insulin-like growth factor binding protein (IGFBP) concentrations in plasma during the pre- and immediate postweaning period, when calves were offered a high or low plane of whole milk. Twenty-six female Holstein calves were randomly assigned to either a high (HI; 10 L/d; n = 13) or low (LO; 5 L/d; n = 13) plane of milk following colostrum feeding at d 3 of life. Calves were fed their respective diet as whole milk until d 48 when a 10-d weaning transition began. During this transition, milk was reduced by 10% per day such that all calves received no milk on d 59 of life. Blood samples were collected bi-weekly to measure IGF-1 and IGFBP in plasma. Calves fed HI gained more body weight than calves fed LO during the preweaning period (d 1–48 of life; 0.90 vs. 0.65 kg/d); however, no differences in average daily gain or metabolizable energy intake during the weaning transition (d 48–58 of life) or postweaning period (d 59–70 of life) occurred. Concentrations of IGF-1 were higher in HI calves during the preweaning period, which was associated with high levels of IGFBP-3 at wk 5 and lower IGFBP-2 during each measured time point preweaning as compared with LO. Insulin-like growth factor binding protein-4 was lower in HI calves only during wk 1, and IGFBP-5 was not affected by the dietary treatment. Overall, offering a high plane of nutrition was associated with changes in plasma IGF-1 and IGFBP that would indicate greater growth and development preweaning but not necessarily postweaning.     

Differing planes of pre- and postweaning phase nutrition in Holstein heifers: I. Effects on feed intake,growth efficiency,and metabolic and development indicators

The objectives of this study were to determine the effects of pre- and postweaning planes of nutrition on feed and metabolizable energy (ME) intake, growth, concentrations of glucose, insulin, insulin-like growth factor 1 (IGF-1), and β-hydroxybutyrate (BHB) in blood and rumen volatile fatty acids (VFA) from birth to 25 wk of age in Holstein heifers. Heifer calves (n = 36) were randomly assigned to receive either a low (5 L/d of whole milk) or high (10 L/d of whole milk) preweaning plane of nutrition from 1 to 7 wk of age, and either a low (70% concentrate dry total mixed ration) or high (85% concentrate dry total mixed ration) postweaning plane of nutrition from 11 to 25 wk of age. From birth to 25 wk of age, feed intake was recorded daily, and body measures were obtained weekly. Circulating hormone and metabolite concentrations were measured biweekly and total ruminal VFA, fecal starch, and body condition were assessed monthly. Overall, average daily gain and body weight were greater for heifers offered increased planes of nutrition during both the pre- and postweaning phases. Heifers offered the high preweaning plane had greater milk intake (7.7 ± 0.1 vs. 4.5 ± 0.1 L/d) but lower starter intake (0.3 ± 0.04 vs. 0.7 ± 0.04 kg/d) during the preweaning phase than those offered the low plane. High preweaning plane heifers also had greater ME intake from wk 1 to 7, but less ME intake at wk 9 (5.3 ± 0.3 vs. 6.6 ± 0.2 Mcal/kg) than those offered the low plane. Furthermore, overall glucose (118.8 ± 2.9 vs. 110.1 ± 2.9 mg/dL) and IGF-1 (101.6 ± 3.6 vs. 75.9 ± 3.6 ng/mL) concentrations were greater for high versus low preweaning plane heifers, although circulating insulin and BHB did not differ between preweaning plane groups. However, heifers offered the high preweaning plane had reduced total rumen VFA concentrations compared with heifers offered the low plane in the preweaning phase (47.3 ± 2.0 vs. 55.6 ± 2.1 mM). During the postweaning phase, dry matter intake and ME were consistently greater in heifers offered the high postweaning plane. Overall insulin (2.0 ± 0.1 vs. 1.8 ± 0.1 ng/mL), glucose (97.1 ± 0.6 vs. 92.1 ± 0.6 ng/mL), IGF-1 (178.0 ± 4.8 vs. 155.8 ± 4.8 ng/mL), and BHB concentrations (8.8 ± 0.2 vs. 8.1 ± 0.2 ng/mL) were greater in heifers offered the high than the low postweaning plane. In addition, heifers offered the high postweaning plane had increased VFA concentrations in the postweaning phase (73.4 ± 1.3 vs. 63.9 ± 1.3 mM) compared with heifers offered the low postweaning plane. The results indicated that increasing the pre- and postweaning planes of nutrition along with energy levels positively influenced several indicators associated with heifer development before 25 wk of age. Nevertheless, there was limited interaction in growth and development indicators between the 2 phases.     

Soymilk as a novel milk replacer to stimulate early calf starter intake and reduce weaning age and costs

The primary objective was to determine the effects of partial replacement of whole milk with soymilk on preweaning calf performance and weaning costs. Following 3 d of colostrum and transition milk feeding, 18 male and 9 female neonatal Holstein calves (41.6 ± 1.6 kg of body weight; mean ± SE) were assigned in a completely randomized design to 3 treatments offered at 10% of body weight (wet basis) including 1) whole milk (control), 2) 75% whole milk + 25% soymilk (S25), or 3) 50% whole milk + 50% soymilk (S50). The weaning criterion was defined as the calf age at a daily intake of ≥900 g of starter concentrate. During the first 2 wk of the experiment, treatments did not differ in starter intake and fecal score. Calves fed S25 gained similar amount of body weight as calves fed whole milk diet. By 49 d of age, also, calves on S25 gained similar body weight as did calves on whole milk diet. Calves on S25 and S50 achieved the weaning criterion, respectively, about 10 and 12 d earlier than did peers on whole milk. The soymilk-fed calves consumed less milk than control calves to meet the weaning criterion owing to promoted starter intake. Feed-related weaning costs dropped by about 35% when soymilk was fed because whole milk was about 50% more expensive than both soymilk and starter concentrate. Feeding soymilk at up to 50% of the milk diet maintained health during the first 2 to 4 wk of age when the neonate calf is highly sensitive to nonmilk proteins and plant antinutrients. Results introduce soymilk as an economic partial substitute for whole milk in calf-raising facilities.     

Effects of feeding milk replacer once versus twice daily on glucose metabolism in Holstein and Jersey calves

Eighteen Holstein (experiment 1) and 15 Jersey (experiment 2) heifer calves were fed milk replacer once or twice daily to determine effects of feeding frequency on weight gain, starter intake, and glucose metabolism. Body weights were measured weekly from birth to 8 wk. Blood samples were collected at wk 1 through 6 from all calves before and at 30, 60, 90, 120 and 180 min after the morning feeding. Plasma was analyzed for glucose, insulin, glucagon, and nonesterified fatty acids (NEFA). Urine was collected 90 min postfeeding to measure glucose concentration. Treatment did not affect mean starter intake or body weight. In experiments 1 and 2 mean plasma glucagon, glucose, NEFA, and insulin and urinary glucose concentrations were not affected by treatment. There was an interaction of sampling time and treatment for plasma insulin concentrations but not for glucose concentrations in both experiments. Following feeding, calves fed milk replacer once daily had higher insulin concentrations than those fed twice daily. There was an interaction of sampling time and treatment for plasma NEFA concentrations in Jersey calves only. Jersey calves fed milk replacer once daily had higher plasma NEFA concentrations before the morning milk replacer feeding. At wk 3 and 6, frequently sampled intravenous glucose tolerance tests were performed to assess glucose effectiveness, insulin sensitivity, and acute insulin response. In experiments 1 and 2 glucose effectiveness and insulin sensitivity were similar regardless of milk replacer feeding frequency. In Holstein and Jersey calves fed milk replacer twice daily, acute insulin response was greater than in calves fed once daily. However, insulin sensitivity decreased with age, while acute insulin response increased with age. These data suggest that feeding calves milk replacer once daily did not deleteriously affect performance or glucose metabolism regardless of breed.     

Growth, health, and blood glucose concentrations of calves fed high-glucose or high-fat milk replacers

The influence of age, carbohydrate-fat ratios of milk replacers, and development of ruminal function on growth, health, and blood glucose concentrations were evaluated in calves. Colostrum-fed, 3-day-old Holstein bull calves were fed to 12 wk on one of three dietary treatments: 1) a high carbohydrate, low fat (60.5% glucose, 9.5% lactose, and 3% lard) milk replacer; 2) a low carbohydrate, high fat (23% glucose, 12.5% lactose, and 30% lard) milk replacer; and 3) weaning at 6 wk of age from high-fat replacer to a standard calf starter. The high fat milk replacer was superior to low fat milk replacer for total weight gains and efficiency of feed conversion. Rates of weight gain of starter calves were similar to those of calves fed low fat. Calves fed the diet with low fat had a high incidence of diarrhea, an occasional outbreak of a yeast-related ethanol intoxication syndrome, and high concentrations of glucose in urine. Irrespective of milk replacer composition or development of ruminal function, plasma and whole blood glucose concentrations declined rapidly in the first 6 wk. Corpuscular glucose declined steadily with age in all calves. This age-related decrease of blood glucose concentration of calves seems to be a constitutive phenomenon.     

Effects of pulse-dose ruminal infusion of butyrate on plasma glucagon-like peptide 1 and 2 concentrations in dairy calves

Feeding of butyrate was found to have a positive effects in enhancing gut development and improving growth performance of calves. Equally, glucagon-like peptide 1 and 2 (GLP-1 and GLP-2), secreted from gastrointestinal L-cells in response to nutrient intake, were found to play a significant role in regulating blood glucose homeostasis and improving gut health. However, limited information is available about the relationship between butyrate and release of GLP-1 and GLP-2 in dairy calves. The objective of this study was to evaluate the effects of a pulse-dose ruminal infusion of butyrate on plasma GLP-1 and GLP-2 concentrations in dairy calves. Five ruminally cannulated mature Holstein bull calves (7.2 ± 0.10 mo, and 330 ± 16.0 kg of body weight; mean ± standard deviation) were used in a 5 × 5 Latin square with 4-d periods. On d 1 of each period at 0800 h, calves were ruminally infused with 1 of 5 treatments: 0 (saline), 0.3, 0.6, 0.9, and 1.2 g of butyrate per kg of body weight. Before butyrate infusion, calves were not offered feed overnight, and sequential blood and rumen fluid samples were taken before and after infusion on d 1 of each period. Ruminal butyrate and total volatile fatty acid concentrations increased linearly (2.65, 12.19, 20.99, 30.19, and 36.30; 23.68, 33.07, 40.94, 51.13, and 56.31 µmol/mL, for butyrate and total volatile fatty acids, respectively) in a dose-dependent manner, whereas propionate and isobutyrate increased quadratically. Ruminal and plasma butyrate, β-hydroxybutyrate, GLP-1, GLP-2, insulin, and glucose concentrations were all affected by treatment, time (except GLP-2), and interaction of treatment with time (except GLP-1). The area under the curve (AUC) summarized at different time points relative to the baseline (AUC30, AUC60, AUC120, and AUC240) for ruminal and plasma butyrate, and BHB, increased linearly with the dose of butyrate infused. However, AUC30, AUC60, AUC120, and AUC240 for plasma GLP-2 concentration were affected in a cubic manner unlike the linear effect on AUC30 and AUC60 for GLP-1. Plasma GLP-2 was not correlated with plasma butyrate (r = 0.16), GLP-1 (r = 0.03), or BHB (r = ?0.05). This findings suggest that pulse-dosing of butyrate slightly increased both GLP-1 and GLP-2 concentrations at specific time points and this might be promoted by direct or indirect effect of butyrate on the intestinal L-cells.     

β-Hydroxybutyrate (BHB) and glucose concentrations in the blood of dairy calves as influenced by age,vaccination stress,weaning, and starter intake including evaluation of BHB and glucose markers of starter intake

The objective of this research was to determine how blood β-hydroxybutyrate (BHB) and glucose are affected by age, time of day, stress, weaning, forced intake restriction, and voluntary starter intake in calves between 1 and 9 wk of age, and to evaluate if either is an acceptable proxy for starter intake. Holstein calves were fed a 27% crude protein, 17% fat milk replacer at 660 g of dry matter daily along with free-choice starter and water. Calves were weaned on d 42. Jugular blood was sampled at 0800, 1200, and 1600 h, and within 5 min of sampling BHB, and glucose concentrations were estimated using test strips (Nova Max Plus meter, Nova Biomedical Corporation, Waltham, MA). Age effects and time of day were estimated by sampling blood weekly (d 6, 13, 20, 27, 34, 41, and 48). To determine vaccination stress, a Pasteurella vaccine was administered after blood sampling at 0800 h on d 36. Effect of voluntary starter intake was tested by selecting calves for low and high intakes (d 35 to 39) and sampling on d 40, 41, 43, and 44. Starter intake restriction was tested by restricting intake in half of the calves and sampling on d 60 and 61. Data were analyzed with repeated measurements in a mixed model procedure with either within-calf effect (day or week) or within-calf effects (hour, and day or week) included in the model. Time of day did not affect blood BHB and glucose in the first 6 wk. Blood BHB was greater in wk 7 versus wk 1 to 6. Blood glucose was greater in the first 5 wk compared with wk 6 and 7. Blood BHB increased and glucose decreased with increasing starter intake. Blood BHB declined due to vaccination, but glucose was unaffected. Starter intake restriction reduced BHB for 3 d and glucose for 2 d after restriction. Both were affected by time of day. Around weaning (d 40 to 44), BHB and glucose increased with increasing starter intake. In this research, neither blood BHB nor glucose was a good proxy for starter intake. Blood BHB was positively and glucose negatively related to starter intake; however, relationships were weak, variable, and affected by time of day, stress, and intake restriction. Over 30% of calves tested ≤0.2 mmol/L BHB when consuming >1,250 g/d of starter, and test strip increments were 0.1 mmol/L, which represented >25% of the mean blood BHB concentration. In this study, neither blood BHB nor glucose was an acceptable proxy for estimating starter intake.     

Plasma lipid concentrations in preruminant calves fed whole milk with whey protein isolate

The objective was to investigate the acute effects of retinol acetate added to whey protein isolate (WPI) on postprandial changes in plasma retinol (experiment 1) and the acute effects of milk fat added to WPI on triglyceride (TG), chylomicrons and very low density lipoprotein (VLDL), and fatty acid concentrations (experiment 2) in suckling calves at 1 and 6 wk of age. In experiment 1, 16 Holstein male calves were alloted to 2 equal groups. On the days of measurement, the calves were fed at 0900 h whole milk [4% of body weight (BW)] mixed with vitamin A acetate (500,000 IU) with or without WPI (0.04% of BW). At 1 wk of age, significantly higher postfeeding concentrations of plasma retinol were observed in the calves fed milk with WPI. At 6 wk of age, no differences in the plasma retinol concentrations were observed between 2 groups. On the days of measurement in experiment 2, 16 male calves were fed at 0900 h whole milk (4% of BW) with added milk fat prepared by centrifugation from whole milk (2% of BW) with or without WPI (0.04% of BW). The milk supplemented with fat was prepared on the day before the measurement. At 1 wk of age, significant higher postfeeding concentrations of plasma TG concentrations were obtained in the calves fed WPI than in the control calves, immediately after the meal or from 7 h later onward. Plasma chylomicrons and VLDL concentrations at 1 wk of age were significantly higher in the WPI-fed group than in the control group at 8 h postfeeding. In the calves with the WPI diet, plasma concentrations of myristic, palmitic, stearic, oleic, and linoleic acids at 1 wk of age were significantly higher than those in the control calves at 8 h after feeding. However, chylomicrons and VLDL, and fatty acid concentrations did not differ between the 2 groups after feeding at 6 wk of age. Results indicate that WPI increases plasma lipid concentration of preruminant calves only at 1 wk of age. These data are interpreted to indicate that WPI enhances mainly lipid uptake in the intestines of neonatal calves.     

Milk feeding level and starter protein content: Effects on growth performance,blood metabolites,and urinary purine derivatives of Holstein dairy calves

The objective of this study was to investigate the effects of milk allowances equal to 526 g/d as moderate (MOD) versus 790 g/d of milk dry matter as high (HI), and starter diets containing 18% or 23% crude protein (CP), on growth performance, blood metabolites, and purine derivative (PD) excretion in the urine of dairy calves. A total of 52 female Holstein dairy calves (40.8 kg of body weight) were randomly assigned to the experimental diets. The treatments were (1) moderate milk and 18% CP starter diet (MOD-18CP); (2) MOD and 23% CP starter diet (MOD-23CP); (3) high milk and 18% CP starter diet (HI-18CP); and (4) HI and 23% CP starter diet (HI-23CP). Calves had free access to a starter feed and water and were weaned on d 53 but remained in the study until d 73. Urine samples were collected during the preweaning period (for 6 consecutive days between d 35 and 40) and postweaning period (for 6 consecutive days between d 65 and 70) to investigate urinary excretion of PD. Starter feed intake, β-hydroxybutyrate (BHB), and blood urea concentrations were reduced; however, average daily gain (ADG) and blood glucose levels increased in calves fed HI before weaning compared with MOD. During the preweaning period, high milk feeding increased total urinary PD excretion but decreased it after weaning. The 23CP diet resulted in higher feed intake and ADG before weaning and higher excretion of allantoin and total excretion of PD compared with the 18CP diet. The HI-23CP treatment resulted in the greatest withers and hip heights at weaning and final measurement, as well as the highest preweaning blood insulin concentrations. In terms of rumen development, MOD-23CP showed the greatest benefits based on starter intake, blood BHB concentration, and urinary excretion of PD. Based on the higher urinary excretion of PD found in HI-fed calves before weaning, it is possible that milk feeding overestimates estimated microbial yield. The results suggest that feeding starters with a higher proportion of CP may help maintain a more balanced ratio of CP to ME during high milk feeding, to avoid protein deficiency due to low starter intake. When calves are fed a high milk allowance, urine excretion of PD may be misinterpreted as a measure of estimated microbial growth and rumen development; this should be considered during calculations of estimated microbial yield in milk-fed calves.     

Evaluation of a colostrum supplement, with or without trypsin inhibitor, and an egg protein milk replacer for dairy calves

Forty-eight Holstein bull calves were assigned to a 2 x 2 x 2 factorial arrangement in a completely randomized block design. Main effects were colostrum versus a serum-derived colostrum supplement, 0 versus 1 g of trypsin inhibitor added at the initial 2 feedings, and milk replacer containing 0 or 50% CP from whole egg. Calves were bled at 0, 6, 12, 18, and 24 h after birth for determination of serum immunoglobulin (Ig). G. Serum IgG concentrations were lower in calves consuming the colostrum supplement compared with calves consuming colostrum. Apparent efficiency of absorption of IgG was similar. Trypsin inhibitor did not affect IgG concentrations or absorption of IgG. Calves were fed either milk replacer for 28 to 35 d (preweaning phase) and weaned when they consumed 0.7 kg of starter grain for 2 consecutive days. The postweaning phase was from weaning to d 56. Feeding colostrum supplement resulted in higher fecal scores postweaning (1.90 vs. 1.58) and overall (1.85 vs. 1.65) and fewer days medicated preweaning (5.1 vs. 2.2 d) and postweaning (3.9 vs. 1.9 d) and overall (9.0 vs. 4.2 d). Calves were treated for upper respiratory tract infections and diarrhea. Dry matter intake and weaning age were not affected by treatment. Postweaning (1.69 vs. 1.2 kg) and overall (1.22 vs. 1.0 kg), calves that received colostrum and egg milk replacer consumed more dry matter and starter. Postweaning, calves fed colostrum and egg milk replacer had similar or greater body weight and gains compared with calves fed colostrum and milk protein milk replacer. Preweaning, feed efficiency was greater for calves fed colostrum (0.44 vs. 0.34), trypsin inhibitor (0.42 vs. 0.36), and milk protein milk replacer (0.48 vs. 0.30) compared with calves fed colostrum supplement, no trypsin inhibitor, and egg milk replacer, respectively. Trypsin inhibitor increased feed efficiency postweaning. Calves fed trypsin inhibitor and milk protein milk replacer were more efficient preweaning and overall than calves fed trypsin inhibitor and egg milk replacer. Results indicate that the blood derived colostrum supplement did not provide as much IgG as colostrum (4.55 g/L vs. 14.6 g/L, respectively), that feeding 1.0 g of trypsin inhibitor did not enhance serum IgG concentrations, and that the egg milk replacer-fed calves fed colostrum performed nearly as well as calves fed colostrum and the milk protein milk replacer.     

Dietary ascorbic acid and immune response in dairy calves

Colostrum-fed, colostrum-deprived, and colostrum-fed and colostrum-deprived calves fed ascorbic acid (1.75 g/d) in whole, raw milk to 6 wk of age were sampled from 0 to 8 wk of age in order to determine whether ascorbate supplementation would increase plasma Ig concentrations, antibody response to immunization, and disease resistance. Plasma IgG concentrations were lower at 14 and 28 d of age in calves fed ascorbate compared with plasma concentrations in calves not receiving ascorbate supplementation, irrespective of colostrum feeding. Colostrum feeding had no effect on antibody titer to keyhole limpet hemocyanin at any age, but ascorbate-supplemented calves had lower plasma antibody titers to keyhole limpet hemocyanin at 35 and 56 d of age. Calves fed ascorbate had lower clinical scores for diarrhea. Dietary ascorbate does not appear to be immunostimulatory in dairy calves to 56 d of age and appeared to inhibit antibody synthesis. However, at 14 d of age there was an interaction of ascorbate supplementation and colostrum feeding; plasma IgG concentrations were higher in colostrum-deprived calves fed ascorbate then in colostrum-deprived calves not fed ascorbate.     

Short communication: Parameters of abomasal emptying and glucose-insulin dynamics in Holstein-Friesian calves at 2 ages and 2 levels of milk replacer intake

Elevated planes of nutrition in the preweaning period of dairy calf management can increase average daily gain, shorten age at puberty, and increase milk yield. In a previous study, 12 Holstein calves were fed 2 meals/d of 4 or 2 L milk replacer up to 7 wk of age. The objective of the current study was to estimate parameters of abomasal emptying and glucose-insulin dynamics in these calves by fitting a mechanistic model to postprandial appearances of plasma glucose, insulin, and the abomasal emptying marker acetaminophen measured at 4 and 7 wk of age. Higher intake of milk replacer resulted in longer bouts of abomasal emptying at a slower rate. Parameters of glucose and insulin dynamics were not affected by milk replacer intake. However, older calves had decreased insulin-stimulated glucose utilization indicating impaired insulin sensitivity, as well as increased pancreatic responsiveness. Neither of these effects were apparent from i.v. glucose tolerance tests on the calves and may have been related to postprandial gut hormone release. Effects of age on parameters of glucose-insulin dynamics were larger than effects of milk replacer intake. Conversely, effects of milk replacer intake on abomasal emptying were larger than effects of age.     

Feed intake patterns,growth performance,and metabolic and endocrine traits in calves fed unlimited amounts of colostrum and milk by automate,starting in the neonatal period

Feed intake, growth performance, and metabolic and endocrine traits were studied in male calves fed unlimited (GrAL; n = 7) amounts of colostrum for 3 d after birth and mature milk up to d 28 and were compared with calves fed commonly recommended amounts of colostrum and milk (GrRS; n = 7). Calves were fed by automates, and software was available to continuously register the time points and amounts of ingested feed up to 11 d of age. Body weight was measured on d 1, 4, 7, 14, 21, and 28, and blood samples were taken on d 1, 2, 3, 7, 14, 21, and 28 to measure several metabolites and hormones. Feed intake of calves fed GrAL increased from d 1 to 4, then remained stable and was always higher than for calves fed GrRS. Total visits (visits with and without milk intake) were higher for GrRS than GrAL, but visits with milk intake were comparable between groups and meal sizes per visit with milk intake were greater in GrAL than in GrRS. Body weight gain was greater in GrAL than in GrRS in wk 1, but not later. There were significant group differences in plasma concentrations of albumin (GrRS > GrAL), nonesterified fatty acids (GrRS > GrAL), cholesterol (GrRS > GrAL; d 28), insulin (GrAL > GrRS), and cortisol (GrRS > GrAL), but not of immunoglobin G, urea, glucose, triglycerides, growth hormone, and glucagon. In conclusion, calves fed ad libitum were capable of ingesting very large amounts of colostrum and milk, even during wk 1 of life, accompanied by a greater body weight gain in GrAL in the first week, whereas in GrRS, the high number of visits without feed intake indicate that these calves reached no repletion. Compared with calves provided restricted amounts of feed, calves with free access to colostrum and milk were characterized by reduced plasma concentrations of nonesterified fatty acids and by a transiently enhanced insulin and reduced cortisol status.     

Effects of early postpartum sodium salicylate treatment on long-term milk,intake, and blood parameters of dairy cows

Previous research has shown that cows who receive treatment with nonsteroidal anti-inflammatory drugs after calving may have increased milk yield beginning near peak lactation, resulting in greater 305-d milk production. It has not been demonstrated whether this response is associated with greater feed intake following the first 3 wk of lactation. Dry matter intake (DMI) and milk yield were measured daily for 56 cows over the first 120 d in milk. Cows in their second parity and greater were blocked by parity and alternately enrolled 12 to 36 h after calving into 1 of 2 treatments: either 3 daily drenches of water or 3 daily drenches of a similar volume of water containing 125 g of sodium salicylate (SAL) beginning 12 to 36 h after calving. Cows were housed in individual stalls to monitor DMI. Blood samples were collected before calving and on the last day of treatment, as well as at 7, 11, 14, 18, 21, 35, 49, 63, 77, 91, 105, and 120 d in milk. The SAL treatment did not affect estimated 305-d milk, fat, or protein yields (from monthly test days), daily milk yield or components, energy-corrected milk, fat-corrected milk, or DMI; however, an interaction between parity and treatment was observed for DMI, where second-parity SAL cows had decreased intake with no differences observed in older cows. This resulted in a parity by treatment interaction for the ratio of energy-corrected milk to DMI. Similarly, no main effects of treatment were observed for plasma glucose, β-hydroxybutyrate (BHB), or fatty acid concentrations, but we noted interactions between treatment and parity for glucose, BHB, and insulin. Older cows had greater plasma glucose and insulin concentrations and decreased plasma BHB following SAL but no differences were observed in second parity animals. Alterations in glucose and insulin resulted in a tendency for a treatment by time interaction for the revised quantitative insulin sensitivity check index. Feeding behavior was also altered following SAL administration, resulting in fewer but longer meals, as well as a tendency for greater meal weight. A tendency for a treatment by week interaction for inter-meal interval was observed, as well as a parity by treatment interaction for meal weight. Despite the lack of a milk yield response, SAL had a prolonged programming effect on feeding behavior and blood variables over the first 120 DIM, with responses largely dependent on parity.     

Growth performance,nutrient utilization,and health of dairy calves supplemented with condensed whey solubles

Our objective was to evaluate growth performance, nutrient utilization, and health of calves supplemented with condensed whey solubles (CWS). Twenty-four Holstein calves (2 d old) in hutches were used in a 12-wk randomized complete block design study. Calves were blocked by birth date and sex. Treatments were (1) control (CON) with no supplement and (2) 50 g/d of CWS. Preweaning CWS was fed with milk and postweaning CWS was top-dressed on starter pellets. Calves were fed 2.83 L of pasteurized milk 2×/d during wk 1 to 5, 1×/d in wk 6, and weaned at d 42. Calves had ad libitum access to starter pellets and water. Individual intakes of milk and starter pellets were measured daily. Fecal scores (0 = firm, 3 = watery) and respiratory scores (healthy ≤3, sick ≥5), calculated from the sum of scores for rectal temperature, cough, ocular, and nasal discharge, were recorded daily. Body weights (BW), frame growth, and jugular blood samples were taken once every week at 3 h after the morning feeding. Fecal grab samples were collected in wk 12 for analysis of apparent total-tract digestibility. Data were analyzed using MIXED procedures of SAS 9.4 (SAS Institute Inc., Cary, NC) with repeated measures. Total dry matter intake was greater in calves fed CWS compared with CON. Calves fed CWS tended to have greater BW during the postweaning period. Gain:feed, average daily gains, withers heights, and concentrations of plasma urea nitrogen were not different. Concentrations of plasma β-hydroxybutyrate were greater in calves fed CWS compared with CON. Serum glucose concentrations were greater in calves fed CON during the preweaning stage, but similar concentrations were found between treatments during the postweaning stage. Rumen pH, ammonia-N, and total volatile fatty acids were similar between treatments. The acetate:propionate ratio was greater in calves fed CWS. The apparent total-tract digestion of nutrients was similar; however, CON tended to have greater digestion of neutral detergent fiber. Fecal scores were not different, but a treatment by week interaction was observed. Supplementing CWS improved starter intake, postweaning BW, β-hydroxybutyrate, fecal scores, and maintained frame growth.     

Lactoferrin supplementation to dairy calves

Twenty-one Holstein calves (12 bulls, 9 heifers) were used to evaluate the effects of supplemental lactoferrin (0, 1, and 10 g/d) added to colostrum, milk, and milk replacer in a 56-d study. Calves fed lactoferrin (LF) weighed more during wk 2, 3, 4, 5, and 6 than control calves. Calves fed LF had increased preweaning daily weight gains and heart girth gains compared with calves not fed lactoferrin. Calves fed 1 g/d LF had a greater preweaning average daily gain than calves fed 10 g/d of lactoferrin. Hematocrit and serum Fe were unaffected by treatments. Calves were weaned when they had consumed 0.7 kg of calf starter grain for 2 consecutive d and were at least 28 d of age. All calves were weaned by 35 d of age, regardless of starter intake. Calves fed LF consumed more calf starter grain during the preweaning period and met weaning criteria at a younger age. This study indicates that supplementing calf diets with LF is advantageous to calf performance.     

Effect of feeding yeast culture on performance, health, and immunocompetence of dairy calves

Objectives were to determine effects of feeding a culture of Saccharomyces cerevisiae on performance, health, and immunocompetence of calves in the first 70 d of age. Holstein calves (n = 512) at 2 ± 1 d of age were randomly assigned to yeast culture (YC, 218 females and 37 males) or control (223 females and 34 males). Yeast culture was fed at 2% of the grain dry matter. All calves received colostrum during the first 24 h, pasteurized milk thereafter until 60 d of age, and grain was fed ad libitum for the first 70 d of age. Calves were housed in individual hutches, and grain intake was measured 5 d/wk. Body weight was measured at 5, 30, and 68 d of age, and attitude and fecal consistency were scored daily. Incidence and duration of health disorders and treatments were recorded. Neutrophil phagocytic and killing activities and antibody response to immunization with ovalbumin were measured. Concentrations of glucose and 3-hydroxybutyrate were measured in plasma. Grain intake did not differ between treatments and averaged 908 g/d throughout the study. Body weight change, concentrations of glucose, and 3-hydroxybutyrate did not differ between YC and control. Minor effects on neutrophil function were observed, and YC tended to increase the number of phagocytized bacteria and killing of phagocytized bacteria but did not influence humoral immune response. Attitude scores were similar between treatments throughout the study. Almost all calves experienced mild diarrhea during the study, but feeding YC improved fecal scores, reduced days with watery feces, incidence of fever and diarrhea, and risk of health disorders. Because of the high incidence of diarrhea, mortality preweaning was also high, but YC improved survival of calves by decreasing mortality rate past 13 d of age. Income at the end of the study was improved by $48/calf with YC. Feeding yeast culture in grain improved health, minimized frequency of health treatments, and reduced risk of morbidity and mortality in dairy calves.     

Structural growth, rumen development, and metabolic and immune responses of Holstein male calves fed milk through step-down and conventional methods

Structural growth, feed consumption, rumen development, metabolic response, and immune response were studied in Holstein calves fed milk through either a conventional method or a step-down (STEP) method. In the conventional method, calves (n = 20) were fed colostrum and then milk at a rate of 10% of their BW for the entire period of 44 d. In the STEP method, calves (n = 20) were given colostrum and then milk at a rate of 20% of their BW for 23 d, which was reduced (between d 24 to 28) to 10% of their BW for the remaining 16 d. The calves on both methods were weaned gradually by diluting milk with water between d 45 and 49. After weaning, feed consumption, structural growth, and body weight gain were monitored until calves were 63 d of age. At d 63, twelve calves (6/treatment) were euthanized and rumen papillae length, papillae width, rumen wall thickness, and emptied forestomach weight were recorded. At wk 4, 7, and 9, ruminal contents were collected to enumerate rumen metabolites. The STEP-fed calves consumed a greater amount of milk than conventionally fed calves during the pre-STEP (d 1 to 28), post-STEP (d 29 to 49), and preweaning (d 1 to 49) periods. Consumption of starter and hay was greater during the pre-STEP period and lesser during the post-STEP and postweaning (d 50 to 63) periods in calves on the conventional method than on the STEP method. Body weight gain and structural growth measurements of calves were greater on the STEP method than on the conventional method. A hypophagic condition caused by greater milk consumption depressed solid feed intake of STEP-fed calves during the pre-STEP period, and a hyperphagic response caused by a reduced nutrient supply from milk triggered their consumption of solid feed during the post-STEP and postweaning periods. Ruminal pH and concentrations of ammonia, total volatile fatty acids, acetate, propionate, butyrate, and plasma β-hydroxybutyrate were higher in calves on the STEP method and at weaning and postweaning (d 63) were lower in calves on the conventional method. Emptied weight of the forestomach, rumen wall thickness, papillae length, papillae width, and papillae concentration were higher in calves on the STEP method than in those on the conventional method. Blood glucose was lower, and blood urea nitrogen and β-hydroxybutyrate at weaning and postweaning were higher in STEP-fed calves. Serum IgG, IgA, and triglycerides for 1, 2, and 3 wk of age were higher in calves on the STEP method than in those on the conventional method. In conclusion, greater feed consumption, BW gain, and structural growth, and a more metabolically and physically developed rumen were observed in calves on the STEP method than in those on the conventional method.