Influence of dietary sodium bicarbonate on the potassium metabolism of growing dairy calves.

We evaluated the influence of supplemental dietary NaHCO3 on K metabolism of young dairy calves. Thirty-two Holstein and Jersey male and female calves were blocked at 56 to 70 d after birth according to breed, sex, and age and assigned randomly to a 2 x 2 factorial arrangement of dietary treatments for 8 wk: .4% K with 0% NaHCO3, .4% K with 2% NaHCO3, .6% K with 0% NaHCO3, and .6% K with 2% NaHCO3. Feed intake was not affected by dietary KCl or NaHCO3 supplementation, but average daily gain increased with increased K and tended to be reduced by dietary NaHCO3. Plasma K was elevated by increased dietary K but generally was unaffected by NaHCO3. Urinary Ca excretion appeared to be reduced by NaHCO3; urine pH increased with supplemental NaHCO3. Results indicate 1) the K requirement of the growing calf is between .40 and .55% of diet DM, 2) because urinary K excretion was elevated by dietary NaHCO3, the K requirement may be increased when the diet is supplemented with NaHCO3, and 3) average daily gain and plasma K are sensitive indicators of dietary K in the growing calf.     

Influence of sodium bicarbonate on growth and health of young calves

Fifty-four Holstein and Jersey calves were assigned at 4 days of age within breed and sex to one of four treatments: control consisting of colostrum, milk replacer, and starter; buffered colostrum and replacer (.6% sodium bicarbonate) and starter (2% sodium bicarbonate); acidified colostrum (1% propionic), untreated replacer, and starter; and acidified, buffered colostrum (1% propionic, .6% sodium bicarbonate), buffered replacer (.6% sodium bicarbonate), and starter (2% sodium bicarbonate). The feeding regimen was colostrum once daily, day 4 to 14; milk replacer once daily, day 15 to 28; and calf starter ad libitum, day 4 to 84. Bull calves were fed for 42 days and heifers for 84 days. Calves fed acidified colostrum refused more feed and were less efficient from day 4 to 14 than calves fed buffered colostrum. Bulls were more sensitive to acidified colostrum than heifers. Starter intake, total dry matter intake, and average daily gains were similar for all calves during days 4 to 84. Rumen fluid from calves fed diets with sodium bicarbonate was higher in acetate and lower in propionate and lactate than that from calves fed diets without sodium bicarbonate. Sodium bicarbonate improved intake of acidified colostrum during the first 2 or 3 days of feeding but had no other effect on gain or feed intake.     

Influence of feeding fermented colostrum and Lactobacillus acidophilus on fecal flora of dairy calves

Twenty Holstein calves were assigned alternately at birth to diets of 1) fermented colostrum, 2) colostrum treated with 1% propionic acid, 3) whole milk, or 4) whole milk treated with Lactobacillus acidophilus (frozen concentrate culture) at 5 x 10(8) organisms per litter. Diets were fed once daily for 3 wk at 10% of birth weight as the sole source of nutritients. Fecal samples were collected at 0, 7, 14, and 21 days of age and analyzed for coliform and lactobacilli numbers. Fermented colostrum diets did not alter coliform counts in feces of healthy calves. Fecal coliform counts of calves fed L. acidophilus decreased with time. Average fecal lactobacilli counts were lower for the colostrum diets than milk diets. The apparent lowered incidence of scours frequently reported in calves fed fermented colostrum diets was not reflected in major changes in fecal microflora under the conditions of this study.     

Feeding value of fermented waste milk with or without sodium bicarbonate for dairy calves

Effects of feeding waste milk from antibiotic-treated cows on growth, feed efficiency, and incidence of scours of dairy calves were studied. Twenty-four newborn Holstein heifer calves were assigned at random to one of the following treatments: 1) fresh normal milk, 2) fresh waste milk, 3) fermented waste milk, or 4) fermented waste milk plus sodium bicarbonate. Means for fat, crude protein, and total solids in normal milk (3.25, 3.05, and 11.84%) were lower than the same components for fresh waste milk (3.82, 3.42, and 12.59%) and fermented waste milk (4.02, 3.42, and 12.74%). Mean pH's for normal milk, fresh waste milk, and fermented waste milk were 6.6, 6.6, and 5.1. Calves were fed colostrum the first 3 days of life, and their respective treatment milk at 10% of body weight for 42 days. Dry calf feed was offered ad libitum beginning on day 4, and water was available at all times. Mean weight gains (kg) and ratios of average dry feed to gain (kg/kg) for the 42-day treatments were: 1) 19.2, .6; 2) 17.6, .6; 3) 19.6, .7; and 4) 20.1, .6. Incidence of scours was measured as number of days that scours were present per calf during the 42 days. Mean scour days for each group were: 1) 2.0, 2) 1.8, 3) 3.0, and 4) 4.8. There were no detrimental effects on calves fed fresh or fermented milk from cows treated with antibiotics. Addition of sodium bicarbonate did not affect acceptance of fermented milk by calves.     

Short communication: Addition of varying amounts of sodium bicarbonate to colostrum replacer: effects on immunoglobulin G absorption and serum bicarbonate in neonatal calves

Fifty-two dairy calves were blocked by birth date and, within each block, randomly assigned to 1 of 4 treatments to investigate the effects of incremental levels of sodium bicarbonate (NaHCO₃) on IgG metabolism. Treatments were (1) colostrum replacer (CR) + 0 g of NaHCO₃ (control); (2) CR + 15 g of NaHCO₃; (3) CR + 30 g of NaHCO₃; or (4) CR + 45 g of NaHCO₃. Calves were fed colostrum replacer (>200 g of IgG) in one feeding within 45 min of birth (0 h) and 2 L of milk replacer at 12, 24, 36, and 48 h. Only calves born in calving pens from multiparous cows with no dystocia were used in this study. Blood samples were taken at 0, 6, 12, 24, and 48 h postpartum, and serum was analyzed for IgG using radial immunoassay and bicarbonate using spectrophotometry. Feeding increasing levels of sodium bicarbonate had negative linear effects on IgG concentration, IgG apparent efficiency of absorption, and IgG area under the curve, primarily due to the effect of the highest dose of NaHCO₃ (45 g). Sodium bicarbonate treatments had no effect on serum bicarbonate concentration. However, area under the curve of serum bicarbonate increased linearly with the amount of NaHCO₃ fed.     

Short communication: Addition of sodium bicarbonate to maternal colostrum: Effects on immunoglobuling absorption and hematocrit in neonatal calves

Twenty-six Holstein bull calves born from primiparous and multiparous cows without dystocia were assigned in a randomized complete block design to 1 of 2 treatments: pooled maternal colostrum (PMC) or PMC supplemented with 30g of sodium bicarbonate (NaHCO(3)). Calves were fed PMC from 9 different batches containing (mean ± SD) 82.05±8.45g/L of IgG. Calves were fed 2.68L of PMC at birth (referred to as 0h) and 1.32L of PMC 6h later. The total amount of IgG fed was 329.89±34.56g. Calves were fed 2L of milk replacer at 24, 36, and 48h postpartum. The addition of NaHCO(3) had no effect on IgG absorption. Serum IgG concentrations at 0, 6, 12, 24, and 48h postpartum were not different between calves supplemented with or without 30g of NaHCO(3) to colostrum. Area under the curve, apparent efficiency of absorption, and hematocrit were not affected by the NaHCO(3) treatment.     

Influence of dietary sodium and potassium bicarbonate and total potassium on heat-stressed lactating dairy cows

Objectives were to study effects of heat stress, 0 or .85% sodium bicarbonate, 0 or 1.0% potassium bicarbonate, and 1.0 or 1.5% total dietary potassium on production and physiological responses of dairy cows. Eighteen lactating Holsteins were assigned to shade (control) or no shade (heat stress) lots continuously for three consecutive 35-day periods and to different dietary treatments each period. Basal diet was 25% cottonseed hulls and 75% concentrate. Daytime and nighttime feed intake and production were measured the last 2 wk of each period, and milk and blood were sampled the final day of each period. Black globe temperature, rectal temperature, respiration rate, and blood pH were higher in no shade. Daytime intake was 132% greater in shade, nighttime intake was not different between environments. Milk production was about 19% greater for evening and morning milkings in shade. Daytime intake, daytime and nighttime milk production were higher with sodium bicarbonate. Potassium bicarbonate reduced intake and production. Higher total dietary potassium increased total daily milk production. Lactating cows appear adept at withstanding environmental and dietary challenges to acid-base homeostasis. Supplementation of sodium bicarbonate and 1.5% dietary potassium, but not potassium bicarbonate, were beneficial to lactating dairy cows.     

Influence of high dietary aluminum on performance and phosphorus bioavailability in dairy calves

Sixteen male intact Holstein calves averaging 72 kg and 64 d of age were used to study the effects of high dietary Al on calf performance and P bioavailability. The main effects were two concentrations of added aluminum (0 and .20% Al) and two of added P (0 and .22% P). The basal diet contained, by analysis, .132% P, .74% Ca, and .021% Al. The calves were assigned to four treatment groups balanced according to body weight. The four treatments were 1) normal P, low Al; 2) low P, low Al; 3) low P, high Al; and 4) normal P, high Al. Calved had ad libitum access to their respective diets for 7 wk. Metabolism of a single oral 32P dose was determined during wk 6. The adverse effects of high dietary Al include a 17% reduction in feed intake and a 47% reduction in body weight gains. Alkaline phosphatase and plasma glutamic oxaloacetate transaminase activities increased in calves receiving the high Al diets. A negative balance of P and Ca was noted in the calves fed high concentrations of Al. Apparent absorption of 32P was reduced (37%) in calved fed diets high in Al (44% of dose vs. 69%). Urinary excretion of 32P was not affected by dietary Al concentrations. Calves fed the low P (deficient) diet showed significant reductions in feed intake, weight gain, serum inorganic P, bone ash, and P content of bone. Dietary P did not significantly affect 32P absorption. Adding .20% dietary Al severely affects P metabolism and performance of young growing calves.     

Feeding heat-treated colostrum or unheated colostrum with two different bacterial concentrations to neonatal dairy calves

The objective of this study was to determine the effects of feeding heat-treated colostrum or unheated colostrum of different bacterial counts on passive transfer of immunity in neonatal dairy calves. First milking colostrum was collected from Holstein cows, frozen at -20°C, and then thawed and pooled into a single batch. One-third of the pooled colostrum was transferred into plastic containers and frozen at -20°C until needed for feeding (unheated-low bacteria). Another third was heat-treated at 60°C for 30 min and then frozen at -20°C until needed for feeding (heat-treated). The final third of colostrum was transferred into plastic containers, stored at 20°C for bacteria to grow for 24 h (unheated-high bacteria), and then frozen at -20°C until needed for feeding. A total of 30 Holstein bull calves weighing ≥30 kg at birth were systematically enrolled into 1 of the 3 treatment groups. Calves were separated from their dams at birth before suckling occurred. Before colostrum was fed, a jugular blood sample was collected from each calf. The first feeding consisted of 3.8 L of colostrum containing, on average, 68 g of IgG/L using an esophageal feeder between 1.5 and 2 h after birth. For the second and third feeding pasteurized whole milk at 5% of birth weight was fed. Blood samples were collected before colostrum feeding and at 24 and 48 h of age to determine serum total protein (STP) and IgG concentrations. Heat treatment of colostrum at 60°C for 30 min reduced colostrum bacteria concentration yet maintained colostral IgG concentration and viscosity at similar levels to the control treatment. Calves fed heat-treated colostrum had significantly greater STP and IgG concentrations at 24 h and greater apparent efficiency of absorption (AEA) of IgG (STP = 62.5 g/L; IgG = 26.7 g/L; AEA = 43.9%) compared with calves fed unheated-low bacteria colostrum (STP = 57.0 g/L; IgG = 20.2 g/L; AEA = 35.4%) or unheated-high bacteria colostrum (STP = 56.2 g/L; IgG = 20.1 g/L; AEA = 32.4%). High bacteria load in colostrum did not interfere with total protein or IgG absorption or AEA.     

Efficacy of colostrum replacer versus maternal colostrum on immunological status,health, and growth of preweaned dairy calves

Commercially available colostrum replacers (CR) are commonly used when maternal colostrum (MC) is unavailable, for managerial convenience, to ensure quality consistency at first feeding, or in disease control and eradication programs. The objective of this study was to determine the efficacy of feeding First Day Formula (Accelerated Genetics, Baraboo, WI) CR versus pooled MC on immunological status, growth, and health of preweaned dairy calves. A total of 1,220 Jersey and Jersey × Holstein calves born on a California Central Valley dairy farm were assigned after birth to receive either CR or MC following a systematic allocation procedure. Calves assigned to MC were tube fed 2.8 L of MC, and calves assigned to CR were tube fed a total of 500 g of CR (150 g of immunoglobulin G; IgG) mixed into 1.9 L of water at 1 h ± 5 min after the calf was born. A subset of calves was selected for passive transfer (n = 592) and growth (n = 268) analyses. Although both coliform count and total bacteria count were low for MC and CR fed to calves during the study, the predicted probability of calves receiving contaminated liquid feed (coliform count >10,000 cfu/mL) at first feeding was reduced for calves fed CR (1.5%) compared with calves fed MC (6.1%). The mean blood concentration of IgG was lower for calves fed CR than for calves fed MC (19.6 vs. 23.4 mg/mL). However, the apparent efficiency of absorption of IgG did not differ between treatments (34.4 and 35.9% for CR and MC, respectively). Total proteins were lower in calves fed CR compared with MC at 24 h (5.16 vs. 5.84 g/dL, respectively). Calves fed CR were 1.5 kg lighter at weaning and gained 0.03 kg less per day (0.30 vs. 0.33 kg/d, respectively) than calves fed MC before weaning. Height at weaning did not differ between the 2 treatment groups. Calves fed CR tended to have a higher predicted probability of not being treated for diarrhea than calves fed MC (0.142 vs. 0.110, respectively). However, when the disease was present, CR had a higher number of treatment days compared with MC (11.6 vs. 10.8 d, respectively). The hazard ratio of dying did not differ between MC and CR; however, CR calves had a numerically higher risk (hazard ratio = 1.347) of dying compared with calves that received MC. In conclusion, IgG absorption and serum concentration of calves were adequate when calves were fed either CR or MC. The CR-fed calves had a lower probability of receiving contaminated liquid feed and performed similar in terms of health compared with calves receiving high-quality MC, although they were slightly lighter at weaning. Therefore, the CR evaluated in this study is a valid alternative to high-quality (>50 mg of IgG/mL) MC.     

Plasma potassium-lowering effect of oral glucose, sodium bicarbonate, and the combination thereof in healthy neonatal dairy calves

Hyperkalemia is a common complication in neonatal diarrheic dairy calves and is corrected by administration of glucose or sodium bicarbonate. Although the hypokalemic effect of glucose is well established in other species, controversial results are reported for sodium bicarbonate. Our objective was to study the effect and mechanism of action of glucose and sodium bicarbonate on the potassium homeostasis of healthy neonatal dairy calves. Nine healthy neonatal Holstein-Friesian calves underwent 3 oral treatments with 2 L of NaHCO₃ (150 mmol/L), glucose (300 mmol/L), and glucose + NaHCO₃ solution (300 mmol/L + 150 mmol/L) in randomized order. Blood was obtained before treatment (T₀) and at 30-min intervals thereafter. Changes between each time point and T₀ were determined for all parameters. Urine was collected volumetrically to determine total renal potassium excretion over an 8-h posttreatment period. Plasma volume changes were extrapolated from changes in plasma protein concentration. Treatment and time effects were tested with repeated-measures ANOVA. Multivariate stepwise regression analysis using dummy variable coding was conducted to identify associations between changes in plasma potassium concentration ([K]) and changes in plasma glucose concentration ([glucose]), blood base excess, and plasma volume. Oral glucose and sodium bicarbonate treatments decreased [K] by 25 and 19%, respectively, whereas the combination of both compounds caused an intermediate [K] decline (22%). For the glucose treatment, the decline in [K] was only associated with changes in plasma [glucose] (partial R² = 0.19). In NaHCO₃-treated calves, [K] decline was associated with change of extracellular volume (partial R² = 0.31) and blood base excess (partial R² = 0.19). When glucose and NaHCO₃ were combined, [K] decline was associated with changes in plasma volume (partial R² = 0.30), BE (R² = 0.22), and [glucose] (partial R² = 0.03). Our results indicate that glucose lowers plasma [K] mainly through an insulin-dependent intracellular translocation of K, whereas NaHCO₃ causes hypokalemia through hemodilution followed by intracellular translocation of K caused by the strong ion effect. The combination of glucose and NaHCO₃ at the dosage used in this study does not have an additive hypokalemic effect. When combined, hemodilution and strong ion effect have the strongest effect on plasma [K], whereas the insulin-dependent effect of glucose appears to be blunted.     

Pasteurization of colostrum reduces the incidence of paratuberculosis in neonatal dairy calves

In the present study, the potential benefits of feeding pasteurized colostrum were demonstrated in calves born to dams naturally infected with Mycobacterium avium ssp. paratuberculosis. Calves were separated at birth from their dams and randomly allocated into a group fed either the colostrum of their dam (DC; n = 6), followed by feeding the milk of the dam for 3 wk and then milk replacer, or into a group fed pooled pasteurized colostrum (PC; n = 5) from healthy noninfected dams, followed by milk replacer. At 6 wk of age, calves were weaned onto calf starter, housed together, and fed in a similar manner throughout the rest of the 12-mo study. Calves were necropsied at the end of the study, and 25 tissue sites were sampled from each animal and cultured for M. avium ssp. paratuberculosis. Sixteen of the 25 tissue sites were positive for calves across both treatment groups, with 14 of the 16 tissue sites positive for DC calves and 9 of the 16 tissue sites positive for PC calves. The degree of colonization within a tissue was low and variable for calves within treatment groups, and fecal shedding of M. avium ssp. paratuberculosis was minimal during the 12-mo study. As a measure of the early immune response to infection, blood obtained from calves was stimulated in vitro with M. avium ssp. paratuberculosis antigen preparations, and IFN-_Y secretion was measured. Antigen-specific IFN-_Y was consistently greater throughout the study in DC calves (0.95 ± 0.19) compared with PC calves (0.43 ± 0.10). Although long-term benefits are unknown, these results indicate that feeding a source of colostrum from paratuberculosis-free dams may decrease the initial exposure of neonates to M. avium ssp. paratuberculosis, perhaps decreasing dissemination of infection over time.     

Effects of feeding heat-treated colostrum on passive transfer of immune and nutritional parameters in neonatal dairy calves

The first objective of this study was to describe the effect of on-farm heat treatment of colostrum on colostral bacteria counts and IgG concentrations. The second objective was to describe the effect of feeding heat-treated (vs. raw) colostrum on passive transfer of colostral immune and nutritional parameters in neonatal calves. Pooled batches of colostrum were mixed and divided equally: one half was fed raw whereas the other half was fed after heat treatment at 60°C for 60 min using a commercial on-farm batch pasteurizer. Colostrum samples were cultured for total bacteria count and total coliform count and analyzed for total IgG concentration. Forty-nine Holstein calves were fed either raw colostrum (n = 24) or heat-treated colostrums (n = 25) within 1 to 2 h after birth. Serum samples collected from calves at 0 h (precolostrum) and 24 h (postcolostrum) were assayed for serum total protein; IgG, IgA, and IgM concentrations; peripheral total leukocyte counts; neutrophil counts; lymphocyte counts; lymphocyte phenotypes; vitamin A, vitamin E, cholesterol, and β-carotene concentrations. Serum samples collected from 2- to 5-d-old calves were tested for immunoglobulin function via a bovine viral diarrhea virus type I serum neutralization titer and for neutrophil bacterial opsonization activity. On-farm batch heat treatment of colostrum at 60°C for 60 min resulted in lower colostrum bacteria concentrations while maintaining colostral IgG concentration. Calves fed heat-treated colostrum had significantly greater serum total protein and IgG concentrations at 24 h, plus greater apparent efficiency of IgG absorption (total protein = 6.3 mg/dL; IgG = 22.3 mg/mL; apparent efficiency of absorption = 35.6%) compared with calves fed raw colostrum (TP = 5.9 mg/dL; IgG = 18.1 mg/mL; apparent efficiency of absorption = 26.1%). There was no effect of treatment on serum concentrations of IgA, IgM, vitamin A, vitamin E, cholesterol, β-carotene or vitamin E:cholesterol ratio, or on serum bovine viral diarrhea virus type I serum neutralization titers. There was no difference between treatment groups when examining calf plasma total leukocyte counts, neutrophil counts, lymphocyte counts, or neutrophil opsonization activity. However, the latter results were considered inconclusive.     

Addition of sodium bicarbonate to either 1 or 2 feedings of colostrum replacer: effect on uptake and rate of absorption of immunoglobulin G in neonatal calves

Forty Holstein dairy calves were blocked by birth date and sex, and randomly assigned to 1 of 4 treatments within each block to elucidate the effect of feeding regimen and sodium bicarbonate (NaHCO?) supplementation on absorption of IgG from colostrum replacer (CR). Calves received CR containing 191.4 g of IgG fed either in 1 feeding at 0 h (within 45 min of birth), with or without 30 g of NaHCO?, or in 2 feedings (127.6 g of IgG at 0 h, with or without 20 g of NaHCO?, and 63.8 g of IgG at 6 h, with or without 10 g of NaHCO?). The treatments were (1) 1 feeding of CR+0 g of NaHCO?; (2) 1 feeding of CR+30 g of NaHCO?; (3) 2 feedings of CR+0 g of NaHCO?; and (4) 2 feedings of CR+30 g total of NaHCO?. Only calves born with no dystocia were used on this study. Blood samples were taken at 0, 6, 12, 18, and 24h postpartum and were analyzed for IgG using a radial immunoassay. Results indicated that, individually, feeding regimen and NaHCO? treatments had no effect. However, the interaction was significant for 24-h IgG and area under the curve, and showed a trend for apparent efficiency of absorption. Absorption rate data indicated that, for calves fed within 45 min of birth, most IgG absorption occurred in the first 6 h after birth. From 6 to 12 h postpartum, IgG absorption started to decrease; however, IgG absorption remained higher for calves fed in a single feeding than in 2 feedings. These data indicated that NaHCO? may increase IgG absorption when calves are fed colostrum in a single feeding but is not beneficial when colostrum is fed in 2 feedings.     

Addition of sodium bicarbonate to rations of pre- and postpartum dairy cows

Sodium bicarbonate was added to complete mixed rations to evaluate the effect of buffer addition on adaptation to high-energy rations by dairy cows in elderly lactation. Forty-five Holstein cows were assigned to one of three treatment groups: control pre- and postpartum; control prepartum, buffer postpartum; and buffer pre- and postpartum. Rations consisted of 85% chopped grass hay: 15% concentrate prepartum and 60% corn silage:40% concentrate postpartum. On day 4 postpartum, cows were switched abruptly to the postpartum ration for 9 wk. Buffered rations contained .6% sodium bicarbonate prepartum and .7% postpartum. Daily dry matter intake as a percent of body weight for cows fed buffer postpartum (3.51%) was greater than for cows fed no buffer (3.04%) of buffer pre- and postpartum (3.14%). Average production of 4% fat-corrected milk was greater for cows fed buffer postpartum and buffer pre- and postpartum (31.9 kg/day and 31.7 kg/day) than for cows fed no buffer (28.9 kg/day). Milk fat tests were not different. Cows fed the buffered rations lost body weight between wk 1 and 9 as compared to a net gain for cows fed no buffer. Cows fed buffers consumed more dry matter during wk 1 than did cows fed no buffer. Samples of rumen fluid, feces, and serum showed few differences that could be attributed to treatments. Compared to controls, cows fed sodium bicarbonate adapted to rations more rapidly postpartum as indicated by increased feed intake during the first 2 wk and by increased milk production during the first 4 wk of the trial.     

Milk intake before first colostrum in newborn dairy calves. Effect on intestinal transmission of macromolecules

The aim of this experiment was to investigate if ingestion of non-colostrum milk before first colostrum by calves impaired intestinal transmission of macromolecules from colostrum fed to calves 8, 16, and 24 h later. This design reflects the situation when calves are born in housing systems where the cow and her newborn calf are not separated from the herd, which gives the calf opportunity to suckle cows other than the mother. Two groups of eight calves each were fed pooled colostrum three times at 8, 16, and 24 h of age. One of the groups were fed non-colostrum milk 30 min after birth. Marker molecules were used to estimate absorption from each colostrum feeding. Blood samples were taken 8 h after each feeding and at 1 wk of age. At no time was there any significant difference between the plasma IgG means of the two groups. There was no difference in transmission of the marker molecules. It was concluded that early ingestion of non-colostrum milk before first colostrum does not change intestinal permeability to colostral macromolecules.     

Response of dairy cows to sodium bicarbonate and limestone in early lactation

A total of 108 dairy cows at three locations were fed a diet supplemented with sodium bicarbonate and limestone during the first 16 wk of lactation. Complete mixed diets were fed for ad libitum intake and consisted of concentrate and corn silage (60:40, dry matter). The four treatments were: 1) basal diet, 2) basal plus 1.2% sodium bicarbonate, 3) basal plus 1.4% limestone, and 4) basal plus 1.2% sodium bicarbonate plus 1.4% limestone. Dry matter intake was increased for 8 wk by sodium bicarbonate, then decreased from wk 9 to 16. Intake was decreased by limestone alone or in combination with sodium bicarbonate. Sodium bicarbonate increased milk production for 8 wk and 4% fat-corrected milk for 16 wk. Average dry matter intake, milk production, and 4% fat-corrected milk (kg/day) for the 16 wk were: 1) 20.2, 31.1, 27.3; 2) 19.8, 32.0, 28.7; 3) 18.9, 31.4, 27.9, and 4) 18.4, 29.7, 27.2 for diets 1 to 4. Ruminal pH was decreased, and volatile fatty acid concentration was increased by added sodium bicarbonate and appeared to result from increased feed intake. Digestibility of nutrients was unaffected by supplements. Sodium bicarbonate affected regulation of blood and urine pH and concentration of electrolytes more than limestone. Serum magnesium was reduced with sodium bicarbonate, although not beyond normal physiological reference range.     

Effects of photoperiod and glucose-supplemented drinking water on the performance of dairy calves

Long-day photoperiods (LDPP) have been shown to increase milk production in lactating dairy cattle. The objective of this study was to determine the effects of supplemental light and glucose-supplemented drinking water on starter dry matter intake (DMI), water intake, serum and rumen metabolites, and growth performance of calves from birth to 8 wk of age. The experiment was conducted as a completely randomized design with a 2 × 2 factorial arrangement of treatments. The calves were assigned at birth to 1 of 4 treatments: 1) 10 h of light, 14 h of dark (short-day photoperiods; SDPP), ad libitum intake of water, and no glucose supplementation; 2) 10 h of light, 14 h of dark, and ad libitum intake of water supplemented with 50 g of glucose/L; 3) 18 h of light, 6 h of dark (LDPP), and ad libitum intake of water, and no glucose supplementation; and 4) 18 h of light, 6 h of dark, and ad libitum intake of water supplemented with 50 g of glucose/L. Fluorescent lights were used to provide lighting at an intensity of approximately 600 lx at the eye level of calves. The calves were bucket-fed 2 L of whole milk offered twice daily at 0700 and 1600 h and had a free access to a textured calf starter. The calves on LDPP were heavier at d 56 than SDPP calves regardless of level of glucose supplementation. The average daily gain of the calves on LDPP from d 29 to 42 and from d 43 to 56 was greater than for SDPP calves regardless of the level of glucose supplementation. The greater average daily gain of LDPP calves from d 29 to 56 coincided with the greater calf starter DMI of these calves. Body widths through hooks were highly (r = 0.72) correlated with body weights, which in turn were related to calf starter DMI. Calves on LDPP had greater ruminal osmolarity and greater concentrations of acetate, propionate, butyrate, and total volatile fatty acids than SDPP calves regardless of the level of glucose supplementation. Calves on LDPP had lower Ca:P ratio than the SDPP calves regardless of level of glucose supplementation. The concentrations of serum glucose and sodium for the glucose-supplemented calves were greater than for nonsupplemented calves regardless of lighting regimen. These results suggest that LDPP encouraged greater consumption of calf starter, which stimulated faster rumen development in the LDPP calves as evidenced by greater volatile fatty acid concentrations.     

Influence of high dietary lead on selenium metabolism in dairy calves

Metabolism of orally dosed 75Se was studied in 10 intact male Holstein calves that were fed ad libitum a control diet containing no added Pb or supplemented with 1000 ppm Pb as PbSO4 for 4 wk. Lead-supplemented calves did not exhibit any clinical signs of Pb toxicity. Voluntary feed intake was reduced by 9.5% and average daily gain by 23%. Lead content of rib, liver, and kidney increased. Serum glutamic oxaloacetate transaminase activity was increased during the last 2 wk of the experiment in calves fed Pb. In calves receiving supplemental Pb, 75Se absorption, blood concentration, and urine concentration were reduced by 26, 21, and 42%, respectively. Tissue 75Se concentrations were significantly lower in kidney, liver, testicle, pancreas, small intestine, heart, spinal cord, and muscle in calves fed Pb. There was a significant negative correlation (r = -.78) between 75Se and stable Pb concentrations in the liver. It is not clear whether the ingestion of subclinical amounts of Pb could affect the absorption and utilization of Se in dairy calves to the extent of Se deficiency when dairy calves are kept in areas known to be low in Se.     

Effect of drinking water temperature on water intake and performance of dairy calves

Very limited information is available on the effects of drinking water temperature on dairy calves. Therefore, the present experiment was designed to study the effects on performance, health, and water consumption of dairy calves offered drinking water either warm (16 to 18°C) or cold (6 to 8°C). The calves (60 calves/treatment) were housed in an insulated barn in pens (3.0 × 3.5 m; 5 calves in each) providing 2.1 m²/calf. During the experimental period (20 to 195 d of age), the calves had free access to water from an open water bowl (depth 80 mm, diameter 220 mm, 2-L capacity, 1 bowl/pen). During the preweaning period (20 to 75 d of age), all calves received milk replacer (7.5 L/calf daily) and had free access to commercial starter, grass silage, and hay. During the postweaning period (75 to 195 d), the weaned calves had free access to grass silage and hay and were given 3 kg/d (air-dry basis) of a commercial concentrate mixture. During the preweaning period, the water intake of the calves offered warm water was 47% higher than that of the calves offered cold water. Water intake in both treatments increased rapidly during weaning and for a few days following weaning. At 180 to 195 d of age, the calves consumed approximately 18 to 20 L of water daily. Calves offered warm water drank 7 and 8% more water during the postweaning period and overall during the experimental period, respectively, compared with those offered cold water. No treatment differences were observed in dry matter or energy intakes, body weight gains, or feed conversion rates. Furthermore, total serum IgG concentrations of the calves did not differ during the preweaning or postweaning periods. Dairy calves consumed more warm than cold water, but the increase in water intake did not influence feed intake, body weight gain, or health parameters.