Biomedical subjects

J B Holter

Publications and source records attributed to J B Holter.

At least 19 recordsLinked to original sources

PubMed1997

Predicting ad libitum dry matter intake and yield of Holstein cows.

Two data files, one from New Hampshire (n = 3308) and one from Georgia (n = 678), containing 4-wk or weekly means, respectively, of ad libitum dry matter intakes (DMI) and related variables were used to predict DMI and yields of 4% fat-corrected milk and milk protein in lactating Holstein cows. The DMI ranged from 5.9 to 30.4 kg/d, and milk yield ranged from 5.8 to 64.3 kg/d. Because of the lack of data from < 14 d in milk, prediction was not possible for the first 2 wk of lactation. Factors considered for inclusion in the DMI prediction model were parity number (1 or > or = 2), treatment with bovine somatotropin (bST), day of year, days in milk, minimum (nighttime) temperature-humidity index, body weight, 4% fat-corrected milk yield, milk protein yield, and corn silage and total silage percentages in forage dry matter. In separate models, the silage predictors were replaced with more specific descriptors of ration dry matter, including percentages of crude protein, fat (ether extract plus soaps of fatty acids), concentrate, acid detergent fiber or neutral detergent fiber, and forage acid detergent fiber or neutral detergent fiber. The square and sometimes natural logarithm of predictors were included in models, which then were subjected to a stepwise backward elimination option of a multiple regression procedure. Several useful equations were developed to predict ad libitum DMI; the best models accounted for about 80% of the variability in DMI, and standard deviations were < 9% of mean DMI. Depression in DMI related to heat stress was higher in pluriparous cows than in primiparous cows (22% vs. 6%). The negative coefficient for effects of bST treatment on DMI suggested that milk yield increased proportionally more in response to bST than did DMI. About 74 to 77% of DMI predictions were within 2 kg/d of observed DMI.

Animals↗

PubMed1996

Predicting ad libitum dry matter intake and yields of Jersey cows.

Two data files were used that contained weekly mean values for ad libitum DMI of lactating Jersey cows along with appropriate cow, ration, and environmental traits for predicting DMI. One data file (n = 666) was used to develop prediction equations for DMI because that file represented a number of separate experiments and contained more diversity in potential predictors, especially those related to ration, such as forage type. The other data file (n = 1613) was used primarily to verify these equations. Milk protein yield displaced 4% FCM output as a prediction variable and improved the R2 by several units but was not used in the final equations, however, for the sake of simplicity. All equations contained adjustments for the effects of heat stress, parity (1 vs. > 1), DIM > 15, BW, use of recombinant bST, and other significant independent variables. Equations were developed to predict DMI of cows fed individually or in groups and to predict daily yields of 4% FCM and milk protein; equations accounted for 0.69, 0.74, 0.81, and 0.76 of the variation in the dependent variables with standard deviations of 1.7, 1.6, 2.7, and 0.084 kg/ d, respectively. These equations should be applied to the development of software for computerized dairy ration balancing.

Animal Feed↗

PubMed1996

Evaluation of equations based on animal factors to predict intake of lactating Holstein cows.

The accuracy of seven DMI prediction equations based only on animal factors was evaluated with 11 independent data files. Mean square prediction error was used to compare equation accuracy, which was considered to be unsatisfactory when the square root of the mean square prediction error was greater than +/-20% of the observed mean DMI. Robust intake equations that have a tolerable level of prediction errors for most data files would be less risky for practical use than models that are highly accurate for some data files but highly inaccurate for others. The number of independent data files for which equation accuracy was unsatisfactory was used to measure lack of robustness. No equation evaluated was able to predict individual cow DMI with a prediction error that was consistently lower than +/-20% of the observed mean intake. The most robust equation in this study predicted intake unsatisfactorily for 3 of the 11 evaluation data files. Unsatisfactory accuracy for this equation was mainly due to mean bias.

Animal Nutritional Physiological Phenomena↗

PubMed1995

Energy intake and gross efficiency comparisons from calorimetric and field data on the same lactating cows.

Field estimates on gross efficiency were obtained from intake and production data on 30 pluriparous Holsteins cows during wk 5, 7, 9, 11, 13, and 15 postpartum. Energy intake and efficiency from the energy chamber on the same cows were measured during wk 6, 10, and 14 postpartum. Measures of gross efficiency were expressed in terms of the utilization of metabolizable energy or net energy for lactation and maintenance. Within corresponding postpartum periods, chamber measures and field estimates were compared by canonical correlation analysis. All estimates from field data of energy and gross efficiencies closely approximated measures of the same traits from energy chamber data. Variation among cows in traits of energy partition and gross efficiency was similar for field estimates and energy chamber measures. Correlations were > .66 between field estimates and chamber measures on observations of maintenance energy and milk energy. Field estimates and chamber measurements of metabolizable energy and net energy had correlations of .76 and .70, respectively.

Animal Nutritional Physiological Phenomena↗

PubMed1994

No advantage to delaying the introduction of calcium soaps of palm oil fatty acids to early lactation dairy rations.

Holstein cows (n = 105, 39 primiparous) were blocked by parity (1 vs. > 1) and assigned randomly at calving to receive supplemental Ca soaps of palm oil (2.9% fatty acids in dietary DM), commencing on DIM 1, 29, or 57 and ending on DIM 112. Effects on DMI, BW and condition score, and milk yield and composition were studied during 1 to 140 DIM. Control TMR contained 4.4% ether extract (mainly from corn meal and dried distillers grains with solubles), was fed using four grain to forage ratios, and, in early lactation, averaged 60% concentrate, 25% corn silage, and 15% wilted grass silage DM. Delayed supplementation of soaps did not promote higher dietary DMI, resulted in reduced milk fat percentage and yield, tended to decrease 4% FCM yield, and did not significantly influence milk protein content. Supplementation of soaps in wk 1 to 8 did not spare postpartum BW loss, hasten BW regain, or affect the normal change in body condition score. Ad libitum DMI and 4% FCM yield were significantly and negatively correlated (r = -.3) with the proportion of dietary CP that was ruminally undegradable.

Animal Nutritional Physiological Phenomena↗

PubMed1993

Sources of variation in partitioning of intake energy for lactating Holstein cows.

Variation in energy partitioning was quantified. Data were from 34 multiparous Holstein cows using indirect respiration calorimetry during the 6th, 10th, and 14th wk postpartum. For each period, cows were placed in digestion stalls for a 6-d excreta collection, followed by two consecutive 11-h determinations of methane and heat production. Sources of variation among cows were analyzed for gross energy consumed; for fecal, urinary, CH4, heat, milk, and maintenance energies; for tissue energy balance; and for tissue partitioning. Ratios of heat production, energy balance, milk energy, and maintenance energy to intake energy were also analyzed for sources of variation. A within-period model was used that contained fixed effects of treatment, parity, season, and covariates for metabolic BW and SCM. None of the diet or parity effects were a significant source of variation in any of the variables. Season effects were only significant for milk energy and water intake. As a covariate, SCM was highly significant for all variables except energy for heat production and energy for maintenance. However, metabolic BW as a covariate was a significant effect for heat production at wk 10 and 14 postpartum. The significance of metabolic BW differed between periods for most energy partition and efficiency measures. The most significant proportion of the variation in energy utilization was attributable to the energy in the milk.

Animals↗

PubMed1993

Protein-fat bypass supplement for lactating dairy cows.

Holstein cows (n = 46) were fed free choice a silage mixture balanced weekly throughout lactation using 13 and 36% CP grains to individualize CP for each cow; grains contained 15 and 20% of distillers grains with solubles, respectively. Cows were blocked by parity (1 vs. > 1) and assigned at calving to receive a commercial bypass protein-fat supplement at 0 (control) or 6% of weekly projected 4% FCM yield throughout lactation. In peak lactation, supplementation raised dietary fat from 4.3 to 6.0% of DM, NE(L) from 1.64 to 1.70 Mcal/kg of DM, and undegradable protein from 42 to 47% of CP and contributed about 25 and 20% of total CP in early and late lactation. Supplement reduced forage and total DMI significantly, which negated the potential nutritional value of the supplement. Reduction in protein content of milk from supplemented cows was small but significant; BW and yields of milk, SCM, and 4% FCM were not significantly affected by treatment. Supplementation increased fat test in parity 1 cows and lowered it in older cows. In wk 5 to 8, 21 to 24, and 37 to 40 postpartum, cows consumed 100 to 116% of the NRC recommendations of undegradable protein but only 65 to 94% of degradable CP needs; NE(L) intake generally was adequate except for primiparous cows in early lactation. Supplementation lowered Lys intake in early lactation. Addition of rumen-protected fat and undegradable, high quality protein mixture to the diet of lactating cows cannot be effective if its use reduced DMI or if degradable protein intake is inadequate.

Animal Feed↗

PubMed1992

Water partitioning and intake prediction in dry and lactating Holstein cows.

Data from four energy and N balance trials with lactating Holstein cows (n = 329) and one trial with dry cows (n = 60) were used to predict free water intake and water-related traits. Lactating cows were between 36 and 159 DIM and, individually, were allowed ad libitum water and forage (corn silage without or with wilted haycrop silage) plus concentrates; dry cows accessed ad libitum water and single forages (grass, clover, or alfalfa, as hays or as wilted silages, or corn silage) varying in maturity. Intake of DM per day and dietary DM percentage were significant and positively related predictors of free water intake in dry and lactating cows. Daily milk yield (range 16 to 52 kg/d) was related linearly to water consumption (.60 L/kg of milk), and season effect in lactating cows was curvilinear; peak water intake was in late June and nadir in late December. Ration CP percentage (DM basis) affected free water intake only in dry cows; 1 unit of increase resulted in an increase of about 1 kg/d in water intake between 12 and 13% CP. As ration moisture dropped from 70 to 40%, free water intake increased about 7 L/d in dry cows, but this was accompanied by a drop of 15 L/d in total water intake (free plus feed water). Free water intakes were predicted with R2 of .64 and .69 in dry and lactating Holstein cows, respectively. Fecal water and urine outputs also were predicted. We found no significant relationship between DM content of the diet and the resulting ad libitum intake in either dry or lactating cows.

Animal Feed↗

PubMed1992

Energy balance and lactation response in Holstein cows supplemented with cottonseed with or without calcium soap.

Holstein cows (n = 58, 21 primiparous), fed corn and wilted grass silages (63:37, DM basis) for free choice consumption, were assigned to control concentrate or supplemented concentrate during wk 1 to 16 postpartum with linted whole cottonseed (15% of projected DMI) alone or with Megalac (.54 kg/d). Our objective was to examine the effects of fatty acids on energy and N balances, total tract digestibility, and milk fatty acids in wk 7 and 16 and to assess total lactation responses. During balance measurements, fatty acids constituted 4.1, 6.8, and 8.6% of DM in control, oilseed, and oilseed plus protected fatty acid diets. Fat additions reduced fiber digestion (attributed to oilseed) and, to some degree, DMI and milk yield, but enhanced fat test without affecting protein percentage. Supplementary fat increased the proportion of C18:0 in milk at the expense of short-chain fatty acids. Supplemental oilseed with or without protected fatty acids reduced total heat production by 6% and reduced heat in excess of maintenance by 8%. Best estimates of NEL in linted whole cottonseed and of fat in Megalac were 1.81 and 5.69 Mcal/kg of DM. In total lactation, primiparous cows yielded more milk and FCM when fed oilseed plus Megalac and less of each when fed oilseed alone than controls. In pluriparous cows, milk yield was reduced by 2.7 kg/d relative to other treatments when oilseed plus Megalac was fed; FCM yield increased about 2 kg/d only when oilseed was supplemented alone. Overall, data suggest that basal ration fat and oilseed supplementation were too high or that supplementation should have been delayed until feed intake was higher.

Animal Feed↗

PubMed1992

Response of Holstein cows to corn gluten meal used to increase undegradable protein in early or later lactation.

Supplemental corn gluten meal was used to raise CP by 1.1 to 1.5 percentage units and undegradable intake protein from 35 to 39% of CP in the corn-based diet of parity 1 or greater Holstein cows to study effects of undegradability, parity, stage of lactation, and interactions on DMI, milk yield and composition, BW, and related traits during complete lactations. Cows were assigned at calving to treatments (n = 30, 8 primiparous): control, supplement wk 1 to 8 postpartum (early), or supplement wk 9 to 44 postpartum (late). Total lactation means were not affected significantly by treatments. Supplementation with undegradable protein enhanced forage and, thus, total DMI in later lactation by pluriparous cows; it apparently spared BW loss wk 1 to 8 postpartum and enhanced BW recovery thereafter in first lactation cows with no effect in older cows. Effects of supplementation on milk yield were small, and they were negative in early lactation and generally positive in late lactation; effects were positive on fat test in early lactation for both parity categories but distinctly negative for parity 1 cows in late lactation. Supplementation of undegradable protein in late lactation also decreased milk protein content in parity 1 cows and raised it in older cows. Data suggest that Lys may have been first-limiting, followed by Ile in early lactation and Met in late lactation, and that AA adequacy may be more important than undegradability in ration protein balancing. For most traits measured, treatment by parity interactions were significant, indicating that parity 1 cows did not respond in the same way as older ones to protein supplementation.

Amino Acids↗

PubMed1992

Estimating production benefits through simulation of group and individual feeding of dairy cows.

Objectives were 1) to develop DMI and milk prediction equations, 2) to use these equations to simulate group and individual feeding of dairy herds, and 3) to estimate effects of group and individual feeding on FCM production. University of New Hampshire data were used to predict DMI from previous DMI and cow and ration characteristics. The same data were used to predict milk production from DMI and previous milk production. Feeding was simulated for 100 cows over 50 4-wk periods in a number of trials. Effects of individual feeding, additional groups, herd calving intervals, and within-herd variation of annual milk production per cow on daily FCM per cow were isolated in average and high producing herds. Changing from one group to individual feeding can increase daily FCM per cow by .5 to 1.1 kg and two groups to individual feeding by 0 to .8 kg without changing total herd nutrient intake. Reallocation of the same amount of nutrients to two groups instead of one can increase daily milk production by .15 to .8 kg of FCM per cow, reallocation to three groups instead of two by 0 to .6 kg of FCM per cow, and reallocation to four groups instead of three by 0 to .35 kg of FCM per cow.

Animal Feed↗

PubMed1992

Methane prediction in dry and lactating Holstein cows.

Data from six experiments (two with dry cows) were used to predict partitioning of gross energy to CH4 in Holstein cows using selected independent variables, some of which were intercorrelated, and a stepwise backward elimination regression procedure. Methane outputs ranged from 3.1 to 8.3% (mean 5.5) of gross energy intake for 134 dry cow balance trials and from 1.7 to 14.9% (mean 5.2) of gross energy intake for 358 lactating cow energy balance trials. This is equivalent to 176 and 300 g/d or 245 and 419 L/d of CH4 for dry and lactating Holstein cows, respectively. Digestibilites of hemicellulose and neutral detergent solubles were positive predictors, and cellulose digestibility was a negative predictor of CH4 output in dry cows fed all forage diets, but hemicellulose digestibility was not a significant variable for predicting CH4 production by lactating cows fed diets with concentrate and forages. Fiber digestibility generally remained in models to predict CH4 output. Except for one data set, regression equations accounted for 50 to 72% of the variation in percentage of gross energy partitioned to CH4 by Holstein cows. Results confirm that increased concentrate feeding reduces CH4 production. Supplementation of lactation diets with fat generally increases fat digestibility, and this trait was associated with reduced CH4 output. Results enable 1) estimation of CH4 output for calculation of metabolizable energy and 2) computation of the contribution from dairy cows to global warming.

Animal Feed↗

PubMed1992

Weekly balancing crude protein in diets for Holstein cows throughout lactation using one versus two grains.

Holstein cows (n = 72, 28 primiparous) were fed for ad libitum intake a forage mixture (corn and haycrop silages, 63:37 DM) and a 71:29 ratio of two grain mixtures (13.8 and 36.2% CP, DM basis) at 1 kg/2.5 kg of the previous day's milk during 1 to 28 DIM (covariate period). Thereafter, rations were balanced and adjusted for energy and CP weekly based on monthly DHI data, forage analyses, and NRC requirements. Cows were blocked by parity (1 vs. greater than 1) and assigned randomly to receive one grain (blend of 13.8 and 36.2% CP grains, herd mean) or two grains according to individual needs. Daily yields of milk, 4% FCM, SCM, and resulting intakes of grain were higher for cows fed two grains, but the increase in daily DMI and the decreases in daily forage intake and SCM:grain ratio were not significant. Fewer pluriparous cows (3 vs. 8 out of 19) on the two-grain treatment conceived after first service, but overall services per conception (1.97) were equal. Percentage of cows with SCC below linear score 4 (91%) was equal between treatments. Means adjusted by covariate 4% FCM resulted in more modest treatment effects. Advantage of two-grain versus one-grain treatment for milk per day was 7.7% for parity 1 and only 1.6% for parities greater than 1; corresponding responses (nonsignificant) for 4% FCM were 2.8 and 4.3, respectively. Forage DMI depressions on two-grain treatment were not significant. When covariate-adjusted means were used, the advantage in income over feed cost for individualized feeding of CP was $106 and $36/yr per cow in parities 1 and greater than 1 when cows produced 8209 kg (313 DIM) and 8527 kg (320 DIM) of milk, respectively.

Animal Feed↗

PubMed1991

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.

Animal Feed↗

PubMed1990

Effect of prepartum dietary energy on condition score, postpartum energy, nitrogen partitions, and lactation production responses.

Objectives were to examine the effects of feeding to alter body condition at calving on subsequent full lactation production performance and feed intake, on BW and periparturient blood traits, and on complete energy and N balances and ration digestibility during wk 6, 10, and 14 postpartum. Thirty pluriparous Holstein cows were assigned randomly to two energy intakes from wk 33 of previous lactation through the dry period to create either normal (7.2) or thin (5.8) mean body condition scores at calving (9 = fat, 1 = thin). The thin group was fed 0 kg hominy feed daily; the normal group was fed 2.7 kg daily to supplement forage DM available ad libitum during this period. When compared with the normal group, cows in the thin condition group exhibited less negative body fat balance (-206 vs. -507 g/d); similar milk yield, DM intake, N partitions, and nutrient digestibilities; and lower fat test (3.2 vs. 4.1%) during the balance measurements. Whole blood and serum traits were within normal physiological ranges. Full lactation measurements were similar between treatments except that milk fat percentage was lower and DM intake (as percentage of BW), was higher in the thin condition group. Although mean BW at calving was more (651 vs. 599 kg) for normal condition cows, condition scores and BW were not significantly different at 14 wk postpartum; BW curves indicated similar rates of recovery of weight thereafter. Cows considered underconditioned at parturition mobilized less body fat after calving, resulting in reduced milk fat concentration without significant effects on milk yield, protein, SNF, DM intake, or nutrient utilization.

Adipose Tissue↗

PubMed1986

Predicting maternal protein and fat balances of growing and mature dry cows.

To examine factors affecting maternal protein and fat changes of dry cows, we fed a diet of silages at varying intakes. Conceptus-corrected balances (fat and protein) were computed and predicted from ration protein and energy densities (digestible, metabolizable, or total digestible nutrients), predry body weight, dry matter intake as percents of body weight or predry body weight, and square or natural log of each. Maximum daily dry matter intake was 1.8% of body weight. Observed energy density did not change with changing intake. Proportion of ingested energy apparently stored increased with dry matter intake/predry body weight, primarily at the expense of heat production. Partition of energy and nitrogen were not significantly affected by this intake expression. Cows in first and subsequent dry periods fed low intakes had positive maternal fat balances at energy intakes equal to or below established maintenance requirements. Body condition score of primiparous cows did not increase and their growth was related to dry matter intake, predry weight, total digestible nutrients, and protein percentage of the diet; daily maternal fat balance followed protein balance (2:1 ratio) up to energy intake 14% above maintenance, thereafter increasing to 4:1 ratio. In older cows, maternal daily fat balance varied primarily with digestible energy density of ration, intake, and to a lesser extent with predry weight and ration protein; protein balance was not closely related to factors studied.

Adipose Tissue↗

PubMed1985

Varying protein content and nitrogen solubility for pluriparous, lactating Holstein cows: lactation performance and profitability.

Effects on total lactation performance of varying ration crude protein (15.3 vs. 13.6% of dry matter) and nitrogen solubility (35 vs. 45% of total nitrogen) in early lactation was studied using 57 pluriparous Holstein cows. Grain was fed according to production so as to minimize change in body weight throughout lactation. Forages high in nitrogen solubility, corn and grass silages, were fed free-choice. Percent concentrate in ration dry matter was highest (64%) 5 to 8 wk postpartum and lowest (3%) 33 to 44 wk postpartum. Protein and nitrogen solubility were varied by formulating four protein supplements fed as 10% of the grain allocation, so differences in treatments applied narrowed as lactation progressed. Cows fed the medium-protein diets produced 196 kg more milk than those receiving low-protein diets, but their peak daily milk yield was only .6 kg higher. Cows receiving rations with reduced nitrogen solubility produced 347 kg more milk than those fed the higher solubility diets, but their peak daily milk yield was 1.0 kg lower. Income above fed cost for the lactation was highest and postpartum loss in body weight was least for cows receiving medium-protein and low-solubility rations in early lactation, but no differences were significant. Both milk yield (38.3 to 40.6 kg) and total dry matter intake (3.74 to 3.91% body weight) means were maximum 6 to 7 wk postpartum, but lactation performance was not proportional to peak milk yield. When cows are fed to minimize body fat mobilization, response to increased protein in the diet is small. Reducing nitrogen solubility of silage-based diets increased milk produced per unit grain fed. There were no adverse effects of treatments on breeding efficiency or herd health.

Animals↗

PubMed1985

Varying protein content and nitrogen solubility for pluriparous, lactating Holstein cows: digestive performance during early lactation.

Thirty-four pluriparous Holstein cows were used to examine effects of crude protein (15.3 vs. 13.6%, dry matter basis) and nitrogen solubility (39.7 vs. 47.9%) on digestibility, energy and protein balances, and related traits during early lactation. Cows were assigned randomly at parturition to treatments in a 2 X 2 factorial arrangement; measurements were during wk 6, 10, and 14 postpartum. Diets were protein supplements (varying in protein content and nitrogen solubility), low-protein concentrate, corn silage treated with urea at ensiling, and wilted grass silage fed individually for ad libitum intake. Reducing nitrogen solubility of diet improved energy intake and productive energy factors but resulted in no significant increase of milk yield or body tissue balances, although body fat balance tended to be higher for low-solubility diets. There was no effect on overall partition of nitrogen in the body. Digestibility of carbohydrates and protein was higher for 15.3 than for 13.6% crude protein diets, resulting in higher total digestible nutrients and digestible and metabolizable energy of dry matter. Raising crude protein in the ration decreased milk yield of cows in early lactation but generally increased body tissue balances. Concentrations of rumen ammonia and blood urea nitrogen were not influenced by nitrogen solubility; increasing dietary protein increased concentrations of both, although not enough to increase consumption of free water. Best digestive efficiency was for animals fed the ration of medium crude protein and low nitrogen solubility.

Ammonia↗