Growth performance of calves fed microbially enhanced soy protein in pelleted starters

Our objective was to determine effects of feeding calves pelleted starters with microbially enhanced (fungi-treated) soy protein (MSP) in replacement of soybean meal (SBM) with different milk replacers (MR). Thirty-six Holstein calves (2 d old; 24 females, 12 males) in individual hutches were used in a 12-wk randomized complete block design study. Treatments were (1) MSP pellets with MR formulated for accelerated growth (28% crude protein, 18% fat; MSPA), (2) SBM pellets with MR formulated for accelerated growth (SBMA), and (3) MSP pellets with conventional MR (20% crude protein, 20% fat; MSPC). Pellets were similar except for 23% MSP or 23% SBM (dry matter basis). Pellets and water were fed ad libitum throughout the study. Feeding rates of MR on a dry matter basis were 0.37 kg twice daily during wk 1, 0.45 kg twice daily during wk 2 to 5, and 0.45 kg once daily during wk 6. Intakes were recorded daily. Body weights, frame size measurements, and jugular blood samples were collected 2 d every 2 wk at 3 h after the morning feeding. Fecal grab samples were collected 5 times per d for 3 d during wk 12 and then composited by calf for analysis of apparent total-tract digestibility of nutrients using acid detergent insoluble ash as an internal marker. Total and starter pellet dry matter intake were greatest for calves fed SBMA and least for MSPC. Calves had similar average daily gain among treatments, but there was a treatment by week interaction and during the last few weeks of the study calves on MSPC had less body weight compared with MSPA or SBMA. Gain-to-feed ratio was similar among treatments; however, there was a treatment by week interaction. Serum glucose was similar among treatments. Plasma urea nitrogen was greatest for calves fed MSPA and least for MSPC. Plasma concentrations of IGF-1 were greatest for calves fed SBMA. Plasma concentrations of triglycerides were greatest for calves fed MSPC. Plasma concentrations of β-hydroxybutyrate had a treatment by time interaction. Treatments had similar total-tract dry matter digestibility, but calves fed MSPC had greater crude protein digestibility than SBMA, with MSPA similar to both. Results demonstrated calves fed pelleted starters with MSP had maintained growth performance with less starter intake compared with SBM.     

Abomasum emptying in young dairy calves fed milk replacers containing animal or vegetable fats

Young Holstein male calves, fitted with re-entrant duodenal fistulae, were fed 25% fat milk replacers containing either butter oil, lard, or corn oil in a 3 X 3 Latin square experiment. Proteins were supplied by skim milk powder. Patterns of changes with time after feeding were observed for the composition and pH of duodenal digesta, recovery rates of fresh and dry matter, rates of abomasum emptying for fresh and dry matter, gastric proteolysis, and diarrhea. The composition and pH of duodenal digesta changed markedly with time after feeding, but the only notable differences between milk replacers were for contents of protein nitrogen and total nitrogen. Recovery rates of fresh matter were higher than 100%, presumably due to salivary and gastric secretions. Dry matter was recovered at a rate averaging 100% suggesting that the method used to measure the flow rate and sample duodenal digesta was adequate. The highest flow rates of fresh matter were during the first 3 h after feeding. Differences were marked among the flow rates of constituents of dry matter. Gastric proteolysis was not influenced by the nature of dietary fats. Fecal dry matter, a measure of the severity of diarrhea, was markedly lower for the milk replacer filled with corn oil than for the other two milk replacers.     

Effects of forage source and forage particle size as a free-choice provision on growth performance,rumen fermentation,and behavior of dairy calves fed texturized starters

We investigated the interactive effects of forage source and forage particle size (PS) as a free-choice provision on growth performance, rumen fermentation, and behavior of dairy calves fed texturized starters. Forty-eight Holstein calves (42 ± 3 kg of body weight) were randomly assigned (n = 12 calves per treatment) in a 2 × 2 factorial arrangement of treatments with the factors of forage source [alfalfa hay (AH) and wheat straw (WS)] and forage PS [(AH: medium = 1.96 mm or long = 3.93 mm) and (WS: medium = 2.03 mm or long = 4.10 mm), as geometric mean diameters]. The treatments were (1) AH with medium PS (AH-MPS), (2) AH with long PS (AH-LPS), (3) WS with medium PS (WS-MPS), and (4) WS with long PS (WS-LPS). Regardless of forage PS, the preweaning starter intake, dry matter intake, metabolizable energy intake, weaning body weight, and forage intake were greater for AH calves than WS calves. Average daily gain, average daily gain/metabolizable energy intake, feed efficiency, and final body weight of the calves did not differ among groups. An interaction of forage source and forage PS influenced acetate, propionate, and acetate-to-propionate ratio in the rumen on d 35, with the greatest acetate proportion and acetate-to-propionate ratio, but the least propionate proportion for AH-MPS calves than the other calves. The total volatile fatty acid concentration and the rumen proportions of propionate (d 70), butyrate (d 35), and valerate (d 35) were greater in AH-MPS calves than in AH-LPS calves. Calves fed AH had greater total volatile fatty acid concentration (d 35 and 70) and propionate proportion (d 70), but lesser ruminal proportions of butyrate (d 35 and 70), valerate (d 35 and 70), and acetate-to-propionate ratio (d 70) compared with calves fed WS. The ruminal valerate proportion (d 70) was greatest in WS-MPS calves than the other calves. An interaction of forage source and forage PS influenced preweaning standing time and starter eating time, with the least standing time for WS-MPS calves and the greatest eating starter time for AH-LPS calves. Calves fed AH spent less time for rumination, but devoted more time to non-nutritive oral behaviors than WS calves. Calves fed forage with long PS spent more time for rumination, eating forage, and spent less time lying and non-nutritive oral behaviors than medium PS. In conclusion, forage source and PS interacted, affecting behavior and rumen fermentation when calves were fed texturized starters. In addition, a desirable ruminal pH in dairy calves can be obtained with texturized starters.     

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.     

Performance of young calves fed soybean protein replacers

In two 12-wk trials we evaluated soybean protein in calf milk replacers. In trial 1, twelve 5-day-old Holstein calves were allotted randomly to three milk replacers. The diets contained 26% crude protein. In trial 2, 18 calves were used and the diet contained 30% crude protein. In trial 1 period 1 (10 to 15 days), mean coefficients of apparent digestibility (%) for milk protein, soy protein concentrate, and full fat soy flour replacers were dry matter 92.0, 70.0, 71.0; protein 90.1, 56.6, 61.3; fat 88.9, 55.0, 53.2;; and ash 85.8, 62.5, 61.2. Average daily nitrogen retentions were 10.8, -1.24, and -.7 g. Results in period 2 (30 to 35 days) for digestibilities and nitrogen retention showed considerable improvement over those in period 1. In trial 2 period 1, mean coefficients of apparent digestibility (%) for milk protein, soy protein concentrate, and defatted soy flour replacers were dry matter 87.5, 66.6, 47.9; protein 80.5, 57.2, 28.5; fat 81.5, 55.9, 33.5; and ash 83.8, 58.9, 48.4. Average daily nitrogen retentions were 10.8, 2.9, and -3.6 g. Results in period 2 for digestibilities and nitrogen retention also showed considerable improvement. Calves are able to use soy based replacers more effectively with age.     

Nutrient digestibility and endogenous protein losses in the foregut and small intestine of weaned dairy calves fed calf starters with conventional or enzyme-treated soybean meal

The aims of this experiment were (1) to compare the effects of a soybean meal with an enzymatic treatment (ESBM) to reduce the concentration of antinutritional factors versus a standard soybean meal (SBM) on foregut and small intestine digestion in weaned dairy calves and (2) to estimate the endogenous losses of crude protein (CP) in the small intestine. Our hypothesis was that a diet containing ESBM instead of SBM would improve ruminal and small intestine digestion and absorption of nutrients. A T-cannula was placed in the duodenum, and a second T-cannula was installed in the distal ileum of 12 Holstein calves at approximately 3 wk of age. Calves were weaned on d 42, and on d 50 they were assigned randomly to a quadruplicated 3 × 3 Latin square with 10-d periods. Digesta samples were collected on d 7 and 8 from the ileum and d 9 and 10 from the duodenum. The diets were fed for ad libitum intake and consisted of a calf starter (CS) of 20% CP with SBM as the main source of protein (CTRL), and an isonitrogenous CS with an ESBM instead of SBM (ENZT). A third diet with a low content of CP (10%) and no soy protein was fed to estimate endogenous N losses and digestibilities of test ingredients. Flows and digestibilities of nutrients were compared between CTRL and ENZT and their test ingredients (SBM vs. ESBM, respectively). Duodenal net flows of CP and total AA as well as ruminal microbial protein synthesis per kilogram of digested CP were greater, and flow of nonprotein N and CP true (corrected by endogenous and microbial flows) foregut digestibility were lower with ENZT than CTRL. The apparent small intestine digestibilities of CP and total AA were greater for ESBM than SBM, but there were no differences between the CTRL and ENZT diets. We observed no differences in digestibilities at the duodenum or ileum of starch or NDF, but true small intestine digestibilities of CP and all AA were greater with ENZT than CTRL. Total endogenous protein losses in the small intestine estimated from calves fed the low-CP with no soy protein diet were 37 ± 1.5 g of CP and 29 ± 1.4 g of AA/kg of DMI. These values may be considered the basal endogenous losses as they are similar to values obtained with the regression method, which estimates N losses when dietary N is null. Our results indicated that the inclusion of an ESBM improved the efficiency of ruminal microbial protein synthesis per digested kilogram of organic matter and CP, and increased CP and AA absorption in the small intestine despite a greater proportion of undigested dietary protein entering the duodenum.     

Influence of decoquinate fed to neonatal dairy calves on early and conventional weaning systems

Forty-four Holstein calves were assigned randomly to treatments in a 2 x 2 factorial arrangement of weaning age (4 or 7 wk) and coccidiostat (treatment or control). The objective of this study was to compare the effectiveness of a coccidiostat, decoquinate, on health parameters and growth of neonatal dairy calves on early and conventional weaning systems. Calves weaned at 4 wk had greater intakes of grain in wk 5 to 7 than did calves weaned at 7 wk. Differences in intakes between weaning groups were not apparent from wk 8 to 24. Fecal coccidia oocyst counts were not affected by age at weaning but were affected by coccidiostat feeding at the rate of .5 mg/kg BW/d offered from 3 d of age and throughout the trial. No effects due to age at weaning or coccidiostat treatment were found in plasma glucose, urea N, and minerals (Ca, P, Na, Cl, K, Mg). Growth parameters were significantly increased in treated animals. Total BW was increased (wk 9 to 24) in treated over control calves (127.3 versus 118.5 kg). Height at withers was also increased in treated calves (95.0 vs. 92.8 cm). Coccidiosis treatment increased growth of dairy calves from 9 to 24 wk, but no interactions were found between coccidiosis treatment and age at weaning.     

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.     

Effects of feeding different carbohydrate sources and amounts to young calves

Corn, oats, molasses, and soyhulls are commonly used carbohydrate sources in calf starters. A total of 180 calves were used in 4 studies to compare the use of these ingredients in calf starters. Study 1 compared textured starters with different amounts of molasses or sucrose. The control starter contained 5% molasses (A). The test starters contained greater concentrations of dietary sugar than starter A as either 10% molasses (B) or 5% molasses plus 1.5% granular sucrose (C). Starters B and C were equal in dietary sugar. Study 2 evaluated textured starters containing 0 or 25% whole oats for calves up to approximately 12 wk old. Study 3 evaluated pelleted starters containing 0 or 62.75% soyhulls for calves up to approximately 8 wk old. Study 4 evaluated textured starters containing 0, 14, 28, and 42% soyhulls for calves between approximately 8 and 12 wk old. Calves were housed in individual pens in an unheated nursery with curtain sides through 8 wk and then in group pens of 6 calves/pen from 8 to 12 wk. Calves were bedded with straw. In study 1, calves fed the starters with extra molasses or sucrose had an average of 9% slower average daily gain (ADG) and greater average fecal scores from 42 to 56 d and 9% slower ADG from 0 to 56 d than calves fed the textured starter with low molasses. In study 2, ADG and feed efficiency (kg of feed/kg of gain) were 22 and 20% less, respectively, in calves fed the starter without oats from 0 to 28 d, but there were no differences thereafter. In study 3, calves fed starters with soyhulls had a 10% slower ADG and 8% lower efficiency of gain from 28 to 56 d than calves fed the starters without soyhulls. In study 4, ADG declined linearly as soyhulls increased in the starter. The change in ADG was 14% from 0 to 42% soyhulls. Replacing corn in a starter with molasses, sucrose, or soyhulls reduced postweaning ADG and increased the cost of ADG. Whole oats were an acceptable substitute for corn.     

Feeding behavior and performance of dairy cows fed pelleted nonroughage fiber byproducts

The potential of pellets made of soy hulls (SH) and corn gluten feed (CGF) to replace starchy pelleted supplement in diets of lactating cows was measured in a feeding regime comparable to automatic milking systems. Twenty-four cows were divided into 2 equal groups and fed for 7 wk in individual feeders monitored by computer on one of the 2 experimental diets. Both diets contained 75% basic total mixed ration plus an additional 25% of pelleted supplement (17% CP), being either high starch pellets (HST) in treatment, or pellets made of SH + CGF (2:1) (SHCG) in treatment. In vitro dry matter digestibility was higher in the HST pellets, whereas neutral detergent fiber (NDF) digestibility was higher in the SHCG pellets. The NDF content was higher in the SHCG diet. Individual cow behavior at the feeding lane was analyzed during the experimental period. Average number of meals and daily eating duration of the SHCG cows were significantly greater, as compared with the HST group. However, intake per meal and rate of eating were greater in the HST cows, whereas meal duration was similar in both groups. Feeding behavior resulted in significantly higher daily dry matter and NDF intake by the SHCG cows (27.1 and 11.1 kg, respectively) as compared with the HST group (24.8 and 7.61 kg, respectively). Consequently, significantly higher milk fat content, milk fat yield, and 4% FCM yield were obtained in the SHCG cows. Milk and milk protein yields were similar in both treatments. Data suggest potential advantages of the SHCG pellets for herds using automatic milking systems.     

Nutrient digestibility of diets with different fiber to starch ratios when fed to lactating dairy cows

The objective of this experiment was to determine whether increasing the dietary neutral detergent fiber (NDF):starch ratio affected NDF digestibility when diets were formulated to have equal in situ NDF digestibility. Six lactating Holstein cows were fed 1 of 3 diets in a replicated 3 x 3 Latin square. All diets had 41.5% of the dry matter (DM) as corn silage but the concentration of corn grain varied from 23.3 to 34.8% and the NDF:starch ratios were 0.74, 0.95, and 1.27. As corn grain increased, the concentration of a mixture of 54% soyhulls and 46% cottonseed hulls decreased. The soyhull:cottonseed hull mixture had the same in situ NDF digestibility as the corn silage. All diets had 18% forage NDF but starch concentration varied from 25.4 to 33.3% and NDF varied from 24.7 to 32.2%. Intake tended to increase as the NDF:starch ratio increased. Total tract digestibility (measured by total collection of feces and urine) of dry matter and energy decreased linearly as the NDF:starch ratio increased, but NDF digestibility was not affected by treatment. Retention of N increased linearly as the NDF:starch ratio increased. As dietary NDF:starch ratio increased, ruminal pH was not affected, but the concentration of total volatile fatty acids (VFA) decreased and the VFA profile was altered by diet. Consistent with the observed changes in ruminal VFA, milk fat percentage increased with increasing dietary NDF:starch. Intake of digestible energy and output of energy in milk and body weight change was not affected by treatment.     

Effects of ad libitum milk intake on dairy calves

Conventional milk feeding for calves (by bucket twice daily at a total of 10% of body weight) was compared with feeding milk for ad libitum consumption from a nipple. Calves were weaned gradually between d 37 and 42 by diluting the milk with water, and body weight and feed consumption were followed until d 63. Calves fed ad libitum drank 89% more milk than calves fed conventionally during the preweaning period, but the ad libitum-fed calves ate only 16% as much calf starter and 17% as much hay. Consumption of starter and hay increased rapidly after weaning, and treatment differences disappeared. Probably as a result of the much higher intake of milk, the ad libitum-fed calves gained 63% more weight than the conventionally fed calves before weaning, resulting in a 10.5-kg weight advantage on d 35. During and immediately after weaning, the rate of weight gain slowed for both treatment groups, but recovered by approximaely d 49. There were no treatment differences in weight gains over the weaning or postweaning periods, and at the end of the experiment on d 63, the calves fed ad libitum maintained an advantage in mean (+/- SEM) body weight (89.07 +/- 2.47 kg vs 81.07 +/- 2.47 kg for the conventionally fed calves). Incidence of diarrhea was low and did not differ between treatment groups. We conclude that ad libitum nipple feeding of milk to dairy calves can allow for increased milk intake and weight gain with no detrimental effects on intake of solid food after weaning.     

Effects of conjugated linoleic acids fed to dairy cows during early gestation on hematological, immunological, and metabolic characteristics of cows and their calves

The aim of the present experiment was to test the stimulation ability of peripheral blood mononuclear cells (PBMC) expressed as stimulation index (SI) of newborn calves and of their dams fed a control fat supplement (CON, n=6) or 50 and 100g/d of a CLA-containing fat supplement (CLA50, n=5, and CLA100, n=6, respectively) during the preceding lactation period for 182 d after calving. The total intake of cis-9,trans-11 and trans-10,cis-12 CLA by groups CLA50 and CLA100 amounted to 4 and 8 g/d each, respectively. For this purpose, blood was collected immediately after parturition from calves before and after colostrum intake, and from cows after parturition and 21 d later. The SI was related to the fatty acid composition of erythrocyte and milk lipids and to various hematological and clinical-chemical parameters. Retrospective evaluation revealed that depletion time (i.e., the individual period elapsed between the day of terminating the feeding of the experimental diet in the preceding lactation period and the day of calving) ranged from 190 to 262 d, which corresponded to fetal exposure times of 19 to 102 d. The SI from cows increased significantly by 77 and 55%, within 21 d after calving according to the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) and Alamar Blue assays, respectively. However, feeding of 50 g of the CLA product failed to demonstrate this increase in the MTT assay. Moreover, SI was significantly lower for calves whose dams belonged to the CLA50 group, whereas stimulation ability was comparable for the PBMC from calves whose mothers were treated with CON and CLA100. Plasma metabolites (total bilirubin, total cholesterol, glucose, nonesterified fatty acids, 3-β-hydroxybutyrate, total protein, and albumin) and hematological parameters (hematocrit, white blood cell profile) were not significantly influenced by dietary treatments of the cows in the preceding lactation period. Although the fatty acid pattern of erythrocyte lipids of cows remained uninfluenced, that of calves showed alterations due to the feeding type of their dams. For example, C16:0 increased significantly from 14.4 to 16.9% of total fatty acid methyl esters, whereas cis-9,trans-11 CLA increased slightly from 0.11 to 0.15% at the same time in calves when their mothers were fed the CLA100 instead of the CON diet. Fatty acid profile of colostrum was significantly different from that of milk after 3 wk for most of the detected fatty acids, but was not influenced by diet type. In conclusion, feeding a CLA-containing fat supplement during the preceding lactation and gestation period exerted effects on the stimulation ability of PBMC from cows and calves for the subsequent parturition. However, CLA dose effects were inconsistent and require further investigation.     

Development of colonic microflora as assessed by pyrosequencing in dairy calves fed waste milk

The objective of the current study was to examine the effect of pasteurization of waste milk, used to feed dairy calves, on the bacterial diversity of their lower gut. Using 16S rDNA bacterial tag-encoded FLX amplicon pyrosequencing, fecal samples from dairy calves, ages 1 wk to 6 mo old and fed either pasteurized or nonpasteurized waste milk, were analyzed for bacterial diversity. Calves were maintained on 2 separate farms and, aside from how the waste milk was treated, were housed and cared for similarly. Fifteen calves were sampled from each age group (1, 2, and 4 wk, and 2, 4, and 6 mo of age; n=90 samples per milk treatment, 180 total samples) on each farm via rectal palpation and the samples shipped and frozen before analysis. In general, bacterial diversity, as represented by the total number of different species, was greater for the calves fed pasteurized waste milk at all ages (except 1 wk of age) and increased with increasing age in both treatments. Proteobacteria, Bacteroidetes, and Firmicutes were the predominant phyla. Differences in phyla and class were observed among treatments and age of calf but with no consistent trends. Salmonella were detected in 9 out of 14 (64%) of the 1-wk-old calves fed nonpasteurized milk. Treponema, an important beneficial bacterium in cattle rumen, was more prevalent in the pasteurized waste milk-fed animals and became higher in the older animals from this group. Escherichia-Shigella were detected among treatments at all ages, and highest at 1 wk of age, averaging approximately 21 and 20% of all bacteria for calves fed pasteurized and nonpasteurized waste milk, respectively, and decreasing as calves aged (2.6 and 1.3%). The consistent detection of Salmonella in the younger animals fed nonpasteurized milk and its absence in all other groups is an important finding related to this feeding practice.     

Detergent fiber traits to predict productive energy of forages fed free choice to nonlactating dairy cattle.

Hay crops that were predominantly alfalfa, clover or grass, and silage corn were harvested at early and late maturities to give a wide range in fiber contents. Hay crops were stored as field-cured hay and wilted silage. Each was fed for ad libitum intake to three or more nonlactating Holstein animals using total collection digestibility and calorimetry to measure DM intake, TDN, digestible energy, and metabolizable energy. Various fiber components (ADF, NDF, lignin), and expressions computed from them, were used to estimate TDN and digestible energy of forages or groups of forages having homogenous relationships. Stepwise backward elimination procedure was employed to discard independent variables or their squared terms at 5% probability to develop significant, biologically sound, practical predictive relationships. Standard NRC equations were used to extend energy densities to NEL. Free choice DM intake of forages (fed alone) was not closely related to NDF percentages. Estimates of NEL generally were higher when computed via TDN as opposed to digestible energy or metabolizable energy, which did not differ. We present equations to predict NEL from ADF via digestible energy for legumes, grasses, and corn silage, which differ markedly, in some cases, from those in current use. Equations for grasses had low r2, but these could not be compared with published ones, which apparently are based on treatment means rather than individual-animal observations. The NEL of hay crops and corn silages also were predicted from an expression of lignified NDF in DM with moderate precision.     

Effects of different physical forms of wheat grain in corn-based starter on performance of young Holstein dairy calves

The objective of the present study was to examine the effects of partially replacing corn with 2 forms of wheat grain on daily intake of starter feed, average daily gain, feed efficiency, rumen pH, fecal score, weaning weight, skeletal growth, and blood metabolites of dairy calves. Thirty-two male and female Holstein dairy calves (n = 8 calves per treatment) were used in a completely randomized block design. At d 3 of age, individually housed calves were randomly allocated to different treatments consisting of a starter diet with 60% ground corn (control), a starter diet with 60% whole corn, a starter diet with 30% ground corn plus 30% ground wheat (GCGW), and a starter with 30% ground corn plus 30% whole wheat (GCWW), with all other components in a meal form. All calves had free access to water and feed throughout the study period and received 4 L of milk replacer/d from d 3 to 50 and 2 L/d from d 50 to 52; weaning occurred at the end of d 52. Feed intake was recorded daily and body weight and skeletal growth measures were recorded on d 10 and every 10 d thereafter. Rumen pH was measured on d 30, 45, and 60. Blood sample were collected on d 30 and every 10 d thereafter through d 70. Data were analyzed using MIXED procedures of SAS (SAS Institute Inc., Cary, NC). Over the experimental period (d 1–70), the starter intake for the GCWW group was significantly different from the control group, but not different from the other groups. Calves fed whole wheat had a significantly greater average daily gain compared with other groups over the experimental period (d 1–70). Feed efficiency was only better in calves fed the GCWW diet than the GCGW group for postweaning and overall periods. No differences were observed for preweaning in body length, hip height, or withers height among the treatments; however, differences were significant in heart girth and body barrel. Postweaning, some of the body measurements were greater in calves fed the GCWW and GCGW starter diets. Blood glucose concentration reduced with age; however, blood urea nitrogen, β-hydroxybutyrate, albumin, and total protein increased with age. Treatment × time effects on blood urea nitrogen and total protein concentrations were detected. Blood urea nitrogen concentration (mg/dL) was affected by dietary treatments on d 30, 40, and 70, but no significant difference was detected on d 50 and 60. Serum total protein concentration (g/dL) was also affected by dietary treatments on d 40 and 70, but no significant difference was detected on d 40, 50, and 60. Whereas rumen pH was significantly reduced for the control compared with the GCWW treatment on d 45, comparison of the fecal scores showed no detectable differences among the treatments. Overall, the results of the current study indicate that starter diets containing whole wheat and ground corn can improve performance in young dairy calves compared with diets containing ground corn/ground wheat, whole corn, or ground corn, under our experimental conditions.     

Effects of dietary protein on milk, rumen, and blood parameters in dairy cattle fed low fiber diets

Eighteen multiparous and 9 primiparous Holstein cows were used to determine the effects of a 13 and 23% crude protein concentrate on milk fat depression during early lactation. Beginning on d 22 postpartum, cows were fed a high fiber diet (27% acid detergent fiber) for 3 wk and then switched to a low fiber diet (9 to 10% acid detergent fiber) for 6 wk. Crude protein percentages calculated from dry matter consumption were 13.5 and 17.9% during the high fiber period and 12.7 and 22.3% during the low fiber period. Daily milk and fat yields for both primiparous and multiparous cows were greater for the high protein treatment. The magnitude of decline in milk fat percentage (from high to low fiber) was greater for the low protein treatment, as determined by nonlinear regression. The high protein treatment was more effective in reducing the severity of milk fat depression in primiparous cows than in multiparous cows. Dietary crude protein had no effect on milk protein or solids-not-fat percentages, rumen volatile fatty acid molar proportions, or serum acetate concentration. The mechanism by which the high protein ration minimized the fat depression response to low fiber rations by primiparous cows is unknown.