Growth, nutrient utilization, and body composition of dairy calves fed milk replacers containing different amounts of protein.

Male Holstein calves < 1 wk of age were allowed a 2-wk adaptation period after purchase, and then were blocked by BW and assigned randomly within block to either a baseline slaughter group or one of four experimental groups (n = 8 to 9 per group). Treatments were isocaloric milk replacers (12.5% solids) fed at 12% of BW that contained 16.1, 18.5, 22.9, or 25.8% CP (DM basis) from whey protein sources. After a 6-wk feeding period, all calves were slaughtered and the weights and chemical composition of the viscera-free carcasses (VFC; including head, hide, feet, and tail) were determined. Gain of BW (0.38, 0.45, 0.56, and 0.62 kg/d) and gain:feed ratio (0.51, 0.59, 0.71, and 0.78) increased linearly (P < 0.001) as dietary CP increased; rate of change in body length, wither height, and heart girth also increased linearly (P < or = 0.05). Balance measurements conducted during wk 3 and 4 of the experimental period showed that both absorbed N (16.9, 20.0, 25.8, and 30.6 g/d) and retained N (7.6, 9.0, 13.2, and 15.6 g/d) increased linearly (P < 0.001) as dietary CP increased. Retained N as a percentage of absorbed N increased linearly (P < 0.01) as dietary CP increased (44.3, 44.7, 50.7, and 50.9%), whereas biological value was unaffected (71.1, 68.7, 69.5, and 67.3%; P = 0.26). Digestible energy and ME represented 94.5 and 89.7% of intake energy, respectively, and were not affected by dietary CP content. Plasma urea N concentration increased linearly (2.9, 3.3, 4.6, and 6.0 mg/dL) as dietary CP increased. Contents of water (68.2, 69.1, 70.2, and 70.5%; P < 0.001) and protein (19.6, 20.0, 20.0, and 20.2%; P < 0.10) in VFC increased linearly, whereas contents of fat (7.2, 6.2, 5.5, and 5.2%; P < 0.001) and ash (5.1, 5.2, 4.8, and 4.7%; P < 0.02) decreased linearly as dietary CP increased. Trends in visceral tissue composition were similar to those for VFC. The content of water in VFC tissue gain increased, whereas contents of fat and energy decreased, as dietary CP increased. Final VFC energy and gain of energy in VFC were not affected by dietary CP. At similar initial ME intakes, increasing dietary CP (i.e., increasing protein: energy) linearly increased ADG, gain:feed, N retention, and deposition of lean tissue in VFC, demonstrating that diet composition can markedly affect components of body growth in preruminant dairy calves.

Factors associated with colostral specific gravity in dairy cows.

The objectives of this study were to identify factors associated with colostral specific gravity in dairy cows, as measured by a commercially available hydrometer (Colostrometer). Colostral specific gravity was measured in 1085 first-milking colostrum samples from 608 dairy cows of four breeds on a single farm during a 5-yr period. Effects of breed, lactation number, and month and year of calving on colostral specific gravity were determined, as were correlations between colostral specific gravity, nonlactating period length, and 305-d yields of milk, protein, and fat. For 75 multiparous Holstein cows, relationships between colostral specific gravity, colostral IgG1, protein, and fat concentrations, and season of calving were determined. Colostral specific gravity values were lower for Brown Swiss and Ayrshire cows than for Jersey and Holstein cows, and lower for cows entering first or second lactation than third or later lactations. Month of calving markedly affected colostral specific gravity values, with highest values occurring in autumn and lowest values in summer. In multiparous Holstein cows, colostral specific gravity was more strongly correlated with colostral protein concentration (r = 0.76) than IgG1 concentration (r = 0.53), and colostral protein concentration varied seasonally (higher in autumn than summer). Our results demonstrate that colostral specific gravity more closely reflects colostral protein concentration than IgG1 concentration and is markedly influenced by month of calving. These results highlight potential limitations of using colostral specific gravity as an indicator of IgG1 concentration.

Effects of yeast culture (Saccharomyces cerevisiae) on prepartum intake and postpartum intake and milk production of Jersey cows.

Yeast cultures (Saccharomyces cerevisiae; YC) have been added to diets for dry and lactating dairy cows to attempt to improve ruminal fermentation, potentially increasing dry matter intake (DMI) and milk yield. Jersey cows (14 primigravid and 25 multigravid) were fed total mixed rations prepartum and postpartum that were either supplemented or not supplemented with YC. The YC was a dried product that was top-dressed at 60 g/d for approximately 21 d prepartum and 140 d postpartum. The DMI was increased by YC during both the last 7 d prepartum (9.8 vs. 7.7 kg) and during the first 42 d of lactation (13.7 vs. 11.9 kg). The treatment-by-day interaction was significant for DMI during the first 21 d postpartum, indicating that cows supplemented with YC increased DMI more rapidly than did nonsupplemented cows. A significant treatment-by-day interaction indicated that cows supplemented with YC lost body weight less rapidly postpartum than did non-supplemented cows. A significant interaction of treatment by day indicated that cows supplemented with YC reached peak milk production more quickly than did nonsupplemented cows. However, total milk produced during the first 140 d of lactation did not differ. Concentrations of fat, protein, lactose, total solids, and urea N in milk, as well as somatic cell count, were not significantly affected by YC. Supplementation of YC increased DMI during the transition period and increased DMI postpartum.

Passive immunoglobin transfer in newborn calves fed colostrum or spray-dried serum protein alone or as a supplement to colostrum of varying quality.

Two experiments were conducted to investigate the effect of serum-derived immunoglobin (Ig) source and the effect of colostrum supplementation with serum-derived Ig on the attainment of passive immunity in newborn colostrum-deprived calves. In experiment 1, colostrum-deprived Holstein bull calves were fed pooled colostrum (PC, n = 9), spray-dried bovine serum (BS, n = 11), or spray- dried porcine serum (PS, n = 9). All treatments were balanced to provide 45 g of IgG in a 2-L volume at birth and again 12 h later. Calves receiving BS had higher 24-h serum IgG concentrations than did calves receiving PC or PS (8.3, 5.7, and 4.2 g of IgG/L for BS, PC, and PS, respectively). In experiment 2, the effect of supplementing bovine colostrum of varying quality with BS on Ig absorption was assessed. Thirty-two colostrum-deprived Holstein bull calves and four freemartin heifer calves were allotted by birth order to receive one of three treatments. Treatments consisted of 1) 2 L of pooled high quality colostrum (95.8 g of IgG, 0% from BS), 2) 2 L of pooled medium quality colostrum mixed with BS (95.2 g of IgG, 47% from BS), or 3) 2 L of low quality colostrum mixed with BS (98.8 g of IgG, 70% from BS). Serum IgG concentrations at 24 h after treatment were greater for calves receiving medium and low quality colostrum supplemented with BS (6.2, 9.6, and 9.6 g of IgG/L for high, medium, and low quality colostrum, respectively). Similarly, apparent efficiency of IgG absorption was greater for calves receiving medium and low quality colostrum supplemented with BS (25, 37, and 38% for high, medium, and low quality colostrum, respectively). The results of these studies suggest that dried BS contains a concentrated source of Ig, which is efficiently absorbed by newborn calves. Supplementation of marginal or low quality colostrum with dried BS is an effective means of improving passive transfer of IgG in newborn calves.

Use of mammary gland and colostral characteristics for prediction of colostral IgG1 concentration and intramammary infection in Holstein cows.

OBJECTIVE: To determine whether mammary gland or colostral characteristics at calving could be used to predict colostral immunoglobulin G1 (IgG1) concentration or intramammary infection (IMI) and whether leakage of colostrum affects IgG1 concentration. DESIGN: Prospective study. ANIMALS: 113 multiparous Holstein cows. PROCEDURE: Cows were examined within 3 hours of calving, and mammary gland and colostral characteristics, colostral volume, somatic cell count, and concentrations of IgG1, fat, and protein were determined. Bacteriologic culture of mammary secretions was performed approximately 14 and 7 days before calving and at calving. Associations of gland and colostral characteristics with colostral IgG1 concentration, colostral volume, and IMI were examined. RESULTS: Thick or thin colostrum had higher IgG1 concentration than colostrum of intermediate viscosity. Colostrum from mammary glands that were firm had low IgG1 concentration. Colostral IgG1 concentration was weakly correlated with volume. Intramammary infection was likely to be detected if colostrum contained clots or blood or if the California Mastitis Test (CMT) score was > or = 2. Somatic cell count was higher for glands with IMI than for uninfected glands, and CMT score was correlated with cell count. CLINICAL IMPLICATIONS: Mammary gland and colostral characteristics were of little value in predicting IgG1 concentration. Our findings do not support recommendations that first milking colostrum that is thin (watery) or that is from cows producing large volumes not be fed to dairy calves. Colostral characteristics, particularly CMT score, were of value for predicting IMI.

Comparison of antibiotic administration in conjunction with supportive measures versus supportive measures alone for treatment of dairy cows with clinical mastitis.

OBJECTIVE: To determine whether antibiotic and supportive treatment would improve outcome for dairy cows with naturally developing clinical mastitis, compared with supportive treatment alone. DESIGN: Randomized controlled trial. ANIMALS: 124 cows in one herd with 172 episodes of clinical mastitis. PROCEDURE: Cows were examined at the onset of clinical mastitis, assigned a severity score, and randomly assigned to receive antibiotic (intramammary administration of cephapirin, i.v. administration of oxytetracycline, or both) and supportive treatment (administration of oxytocin, stripping of affected glands, and, in severely affected cows, administration of flunixin meglumine or fluids) or supportive treatment alone. Treatment was continued until 24 hours after signs of clinical mastitis resolved (clinical cure). Milk samples from affected glands were submitted for bacterial culture before initial treatment and every 2 weeks thereafter until the causative organism was no longer isolated (bacteriologic cure). RESULTS: When mastitis was caused by Streptococcus spp or coliform bacteria, clinical cure rate by the tenth milking was significantly higher if antibiotics were used. Bacteriologic cure rate at 14 days was significantly higher when antibiotics were used, particularly if mastitis was caused by Streptococcus spp. Cows receiving antibiotics developed fewer subsequent episodes of clinical mastitis during the 60 days after the initial episode of mastitis and had less severe clinical disease than cows that did not. CLINICAL IMPLICATIONS: Results suggest that, in herds in which mastitis is often caused by environmental bacteria, antibiotic and supportive treatment may result in a better outcome for cows with clinical mastitis than supportive treatment alone.

Effects of mastitis on the volume and composition of colostrum produced by Holstein cows.

The effects of mastitis during the late nonlactating period on colostral volume and concentrations and total yields of immunoglobulin (Ig) G1, fat, and protein in colostrum were investigated using matched pairs of mammary glands from multiparous Holstein cows. Samples of mammary secretions were collected at approximately 14 and 7 d prepartum and within 3 h after calving. At each sampling time, the glands and secretions were examined for gross abnormalities, and the California Mastitis Test was performed. Duplicate secretion samples from each gland were cultured, and somatic cell count, pH, and fat and protein concentrations were determined. The volume of colostrum obtained at the first milking of each gland was quantified using a quarter milking device, and its IgG1 concentration was measured. Colostral volume from persistently infected mammary glands was lower than that from matched uninfected glands, as was the total mass of IgG1. However, infection did not alter IgG1 concentration in colostrum. Fat and protein percentages were lower in prepartum secretions but not in colostrum from infected glands. Persistent infection was associated with increased somatic cell count and pH of secretions at all sampling times, and California Mastitis Test scores were higher for colostrum from infected glands. The appearance of secretions was extremely variable, but the presence of flakes or clots in colostrum was associated with infection. We concluded that mastitis during the late nonlactating period alters mammary gland function but is unlikely to be an important contributor to the high rate of failure of passive transfer of immunoglobulins in calves.

Use of clinical parameters for differentiation of gram-positive and gram-negative mastitis in dairy cows vaccinated against lipopolysaccharide core antigens.

OBJECTIVE: To determine whether clinical parameters could be used to differentiate clinical mastitis (CM) caused by gram-positive bacteria from CM caused by gram-negative bacteria in dairy cows vaccinated against lipopolysaccharide core antigens. DESIGN: Case series. ANIMALS: 143 episodes of CM in 86 dairy cows in a single herd. PROCEDURE: Cows were examined at onset of CM, and 24 clinical parameters including rectal temperature, heart rate, rumen contraction rate, degree of dehydration, various udder and milk characteristics, lactation number, stage of lactation, and season of year were recorded. Milk production and milk constituent concentrations before onset of CM were obtained from Dairy Herd Improvement Association records. Values for cows with gram-negative CM were compared with values for cows with gram-positive CM. Logistic regression was used to identify important predictors of gram-negative CM. RESULTS: 64 (45%) CM episodes were caused by gram-negative bacteria and 79 (55%) were caused by gram-positive bacteria. Rumen contraction rate was significantly lower and milk protein percentage before onset of CM was significantly higher in cows with gram-negative, rather than gram-positive, CM. Logistic regression indicated that CM was more likely to have been caused by gram-negative bacteria if it developed during the summer, milk was watery, or rumen contraction rate was low. Sensitivity and specificity of the final regression model were 0.58 and 0.80, respectively. Predictive value of a positive result was 0.74 when proportion of CM episodes caused by gram-negative bacteria was assumed to be 50%. CLINICAL IMPLICATIONS: Results suggest that clinical observations do not allow accurate prediction of CM pathogens and should not be the sole criteria for deciding whether cows with CM are treated with antibiotics.

Effects of quality, quantity, and timing of colostrum feeding and addition of a dried colostrum supplement on immunoglobulin G1 absorption in Holstein bull calves.

Three experiments were conducted to examine the effects of quality, quantity, and timing of colostrum feeding and the administration of a dried colostrum supplement on serum Ig in Holstein bull calves. In Experiment 1, calves were fed colostrum that had low concentrations of immunoglobulin (Ig; 23.9 mg of IgG1/ml) as follows: group 1-1 (n = 6), 2 L at birth and 2 L at 12 h; group 1-2 (n = 6), 4 L at birth and 2 L at 12 h; and group 1-3 (n = 6), 2 L at birth, 2 L at 6 h, and 2 L at 12 h. Doubling the volume of colostrum administered at birth did not result in higher serum Ig at 48 h, but additional colostrum at 6 h did increase serum Ig. In Experiment 2, calves received 2 L of colostrum that had low concentrations of Ig (25.7 mg of IgG1/ml) at birth and 2 L at 12 h. Calves in group 2-1 (n = 6) received colostrum only. Calves in groups 2-2 (n = 5) and 2-3 (n = 5) were fed additional dried colostrum supplement (136 and 272 g, respectively) at each meal. Addition of the supplement reduced efficiency of IgG1 absorption and did not result in higher serum Ig at 48 h. In Experiment 3, calves were fed as follows: group 3-1 (n = 6), 2 L of colostrum containing 32.9 mg of IgG1/ml (low Ig) at birth and 2 L at 12 h; group 3-2 (n = 6), 2 L of colostrum containing 60.1 mg of IgG1/ml (high Ig) at birth and 2 L at 12 h, and group 3-3 (n = 5), 4 L of colostrum containing 60.1 mg of IgG1/ml at birth and 2 L at 12 h. Colostrum high in Ig resulted in higher serum Ig concentrations at 48 h; the concentrations were highest when 4 L of colostrum high in Ig were fed to calves at birth.

The relationship of expectancies to outcome in stress management treatment of essential hypertension: results from the Joint USSR-USA Behavioral Hypertension Project.

Outcome expectancy and efficacy expectancy measures were made during the course of a cross-cultural comparison of thermal biofeedback and autogenic training as treatments for mild essential hypertension. There were no differences between groups at either pre- or posttreatment, and expectancy measures were not related to initial success or failure at the completion of treatment. However, both outcome and efficacy expectations were related to relapse over the three months immediately following the completion of treatment. Treatment failures had lower ratings for both outcome and efficacy expectations at the posttreatment assessment in comparison to treatment successes. Implications of these results are discussed.

Comparison of three methods for incorporation of liquid fat into diets for lactating dairy cows.

Two experiments were conducted to determine whether method of incorporation of tallow (iodine value = 57.7) into a TMR for lactating dairy cows affected DMI, milk production or composition, ruminal characteristics, or nutrient digestibilities. In Experiment 1, 8 Holstein and 8 Jersey cows were fed diets containing 1) control, no fat; 2) fat (5% of DM) added first to the concentrate; 3) fat added first to the haylage; and 4) fat added as the last ingredient in the TMR. The DMI was lower when fat was added last to the TMR; DMI was decreased for Jerseys, but not Holsteins, when fat was added first to the concentrate. Milk production was increased, and milk fat percentage decreased, by fat supplementation, but neither differed among application methods. Milk protein percentage was decreased by fat supplementation but was decreased less when fat was added last to the TMR. Production of milk CP, true protein, and casein protein was greater when fat was first mixed with haylage or added last to the TMR. In Experiment 2, four Holstein cows with ruminal cannulas were fed the same diets. Ruminal fermentation characteristics and apparent total tract digestibilities of DM, OM, CP, NDF, ADF, and ash were not different among diets. Digestibility of total fatty acids was decreased when fat was added first to haylage or last to the TMR. Incorporation method had relatively minor effects on variables.

Whole milk and oral rehydration solution for calves with diarrhea of spontaneous origin.

Forty-two calves (mean 10 d of age) that spontaneously contracted diarrhea were used to test the therapeutic value of an oral rehydration solution with or without whole milk. Therapy began on the first feeding after a fecal score was > 2 (five-point scale). Amounts (percentages of BW daily) of milk and oral rehydration solution on d 1 and 2, 3 and 4, 5 and 6, and 7 for treatments 1, 2, and 3 were 1) 0 and 10, 5 and 5, 7.5 and 2.5, 10 and 0% (in two feedings); 2) 2.5 and 10, 5 and 7.5, 7.5 and 5, 10 and 0% (in two feedings); 3) 10 and 10, 10 and 5, 10 and 2.5, 10 and 0% (in three feedings). Oral rehydration solution was fed 15 min after milk. Fecal score, rectal temperature, packed cell volume of whole blood, concentrations of glucose and electrolytes in serum, and strong ion difference of serum were unaffected by treatments. Calves given treatment 3 gained BW throughout the experiment, whereas those given treatments 1 and 2 lost BW during the first 3 d of therapy. Fecal cultures indicated that 70% of calves were infected with Cryptosporidium on d 1 of therapy. No mortality occurred. Whole milk and oral rehydration solution fed to calves did not adversely affect calves or prolong or worsen diarrhea but promoted gain of BW.

Lactation potential as a criterion for strategy of feeding total mixed rations to dairy cows.

A trial was conducted from freshening to 30 wk postpartum to evaluate assignment of cows into production potential groups based on early lactation performance to optimize the time for switching from high to medium nutrient concentration TMR. Cows received a TMR formulated for early lactation until wk 4 of lactation and a high nutrient concentration TMR until 13, 19, or 25; the high TMR was followed by a medium nutrient concentration TMR until the end of the trial. Cows were assigned to high, medium, or low potential groups separately for parities 1, 2, and > or = 3 based on daily 3.5% FCM production as a percentage of BW measured during wk 6 and 7 of lactation. Low potential cows tended to partition energy intake into BW gain earlier in lactation than medium and high potential cows. For low potential cows, an early transfer to medium TMR moderated BW gain with no negative effect on production. High potential cows maintained their BW on the high ration; however, early transfer negatively affected production. Classification of individual cows into potential groups based on early lactation performance can serve as a useful tool for TMR feeding strategy later in lactation.

Effect of extra energy as fat or milk replacer solids in diets of young dairy calves on growth during cold weather.

The effects of feeding two levels of supplemental fat and extra milk replacer solids on Holstein calves housed in hutches during the winter were investigated. Fifty calves (10 per treatment) were assigned to the following dietary treatments: 1) milk replacer (control) reconstituted to 12.5% DM fed at 10% of BW (adjusted weekly), 2) same as treatment 1 plus 113 g/d of supplemental fat, 3) milk replacer reconstituted to 15% DM and fed at 10% of BW (adjusted weekly), 4) same as treatment 1 plus 226 g/d of supplemental fat, and 5) milk replacer reconstituted to 15% DM fed at 14% of BW (adjusted weekly). Half the amount of milk replacer consumed during wk 4 was fed during wk 5, and calves were weaned to dry feed at 35 d of age. A pelleted starter was offered for ad libitum intake throughout the 42-d trial. Gains in BW were greater for calves fed 226 than 113 or 0 g/d of supplemental fat (d 3 to 28). Calves fed milk replacer reconstituted to 15% DM at 14% of BW had greater BW gains during d 3 to 28 than control. Starter consumption was similar between groups receiving 113 and 0 g/d of fat supplement but lower in the group fed 226 g/d. Extra milk replacer solids in diets increased fecal scores to levels greater than those of calves in other groups. The benefit of fat supplementation of milk replacers was manifested as increased BW gain during the 1st mo of life.

Identification of the homozygous recessive genotype for the deficiency of uridine monophosphate synthase in 35-day bovine embryos.

Holstein-Friesian cattle heterozygous for the deficiency of uridine monophosphate (UMP) synthase have half-normal activity of UMP synthase. The homozygous recessive genotype would result in little or no activity, has not been observed among live animals and apparently leads to embryonic mortality at approximately Day 40 of gestation. Activity of UMP synthase averaged 2.74 +/- 0.61 units/mg protein for 19 obligatory normal embryos (from normal x normal matings). Activity for 18 embryos from heterozygote x heterozygote matings yielded three non-overlapping groups as follows: (i) five presumed normals with greater than two-thirds normal activity, (ii) ten apparent heterozygotes with one-third to two-thirds normal activity and (iii) three putative homozygous recessive embryos with less than one-third normal activity. The distribution among these groups was consistent with the 1:2:1 ratio expected for autosomal inheritance. Conception of embryos homozygous recessive for this disorder was demonstrated.

A preliminary investigation of prediction of mean arterial pressure after self-regulatory treatments.

This study investigated the ability of pretreatment variables from three different domains (social-demographic, psychological, and psychophysiological) to predict posttreatment mean arterial pressure (MAP) for 59 unmedicated males with mild hypertension who were participating in a cross-cultural (USA-USSR) comparison of autogenic training and thermal biofeedback to a self-relaxation control. The overall multiple regression equation consisted of two variables and indicated that higher diastolic blood pressures during a cold pressor task were predictive of greater MAP reductions while higher scores on the Irritability subscale of the Buss-Durkee Hostility Scale were predictive of less MAP reductions. Suggestions for future research in this area are provided.

Changes in plasma norepinephrine to combat-related stimuli among Vietnam veterans with posttraumatic stress disorder.

Plasma norepinephrine samples were obtained before and after exposure to auditory stimuli reminiscent of combat from two groups of male Vietnam veterans with combat experience: one with diagnoses of PTSD (N = 15) and one with no mental disorder (N = 6). Results showed a significant 30% rise in plasma norepinephrine for the PTSD group, with no change in the comparison group.

Evaluation of thermal biofeedback treatment of hypertension using 24-hr ambulatory blood pressure monitoring.

Ten male hypertensives, whose BPs were controlled on a combination of sympatholytic and diuretic medications, were given 16 sessions of thermal biofeedback prior to attempting withdrawal from the sympatholytic drug. Results were evaluated using 24-hr ambulatory BP monitoring (ABPM) as well as clinic and home BPs, both in multi-baseline-across-subject designs and as a single group. Results showed significant treatment effects on 24-hr ABPM data, both at the individual level (SBPs only) and in the aggregate analyses (SBP and DBP). BPs assessed in the clinic by random zero sphygmomanometer and patient-assessed home BPs were also reduced.

Effects of feed processing and frequency of feeding on ruminal fermentation, milk production, and milk composition.

Twenty Holstein cows, averaging 108 d postpartum, were used in five replicated 4 x 4 Latin squares to investigate the effects of feed processing and frequency of feeding on ruminal fermentation, milk production, and milk composition. Four rumen-fistulated cows were used in one of the replicates to monitor ruminal fermentation. Each cow was fed for ad libitum intake a diet of 55% alfalfa and 45% concentrate on a DM basis. Treatments were 1) noncubed diet fed two times daily, 2) noncubed diet fed four times daily, 3) cubed diet fed two times daily, and 4) cubed diet fed four times daily. Alfalfa was fed as long hay in the noncubed diet and chopped and pressed into a cube in the cubed diet. Dry matter intake by cows was not different between treatment comparisons. However, cows fed the noncubed diet consumed 5% more concentrate and 5% less alfalfa than did cows fed the cubed diet. Milk production was greater (1.4 kg/d) when the cubed diet was fed to cows, but the percentage and yield of milk fat were depressed (.43 percentage units and .09 kg/d), causing a decreased production of 4% FCM (.9 kg/d). The depression in milk fat percentage and yield may have been attributed to lowered ruminal fluid pH and a decreased ratio of acetate to propionate in cows consuming the cubed diet. Even though ruminal fluid pH and the ratio of ratio of acetate to propionate tended to be lower when cows were fed four times rather than two times per day, production and composition of milk were not affected by frequency of feeding the diets.

Feeding acidified or sweet milk replacer to dairy calves.

The objective of this study was to compare performance of calves fed acidified milk replacer or regular (sweet) milk replacer twice daily at 10% of BW. Thirty-seven female Holstein calves were fed replacers reconstituted to 12.5% DM for 4 wk, At 28 d, half of the amounts of milk replacer consumed during wk 4 were fed during wk 5 and calves weaned from replacer at d 35 age. A pelleted starter feed was offered for ad libitum access throughout the 42-d trial. Body weight was recorded at birth, d 3 of age, and weekly thereafter. Fecal consistency scores were recorded. Other parameters were measured on d 3 and 42. Average daily gains (d 3 to 42) for calves fed sweet and acidified milk replacers were .33 and .38 kg/d. Starter consumption was similar for both treatments. Calves fed acidified milk replacer (d 3 to 28) had a lower (1.4 vs. 1.6) fecal consistency score than those fed sweet milk replacer (scale of 1 to 4, 1 = normal and 4 = watery). Benefits of feeding acidified milk replacer at 10% of BW per day may be in reducing the incidence of some infectious scours, although further experiments are needed to verify this.