Influence of transition diets on occurrence of subclinical laminitis in Holstein dairy cows.

Pre- and postpartum diets varying in energy and fiber were studied for effects on subclinical laminitis in Holstein cows. Also, ruminal acidosis was examined relative to sole hemorrhages and ulcers. Cows (n = 98) were assigned to a 2 x 2 factorial arrangement of treatments in a randomized complete block. Diets high in net energy of lactation (NE(L)) and low fiber were classified as high NE(L), whereas low NE(L) and higher fiber were defined as low NE(L). Two diets were fed for 3 wk before calving and 2 others fed for 3 wk postpartum resulting in 4 treatment combinations: high NE(L), low NE(L); high NE(L), high NE(L); low NE(L), low NE(L); and low NE(L), high NE(L). Levels of NE(L) (Mcal/kg DM), percentage of acid detergent fiber, and percentage of neutral detergent fiber for low NE(L) vs. high NE(L) prepartum diets, were 1.51, 30.2, 47.2 vs. 1.65, 23.4, 39.8, respectively, and 1.70, 22.4, 36.8 vs. 1.77, 17.5, 31.4 for low NE(L) vs. high NE(L) lactating diets, respectively. A single diet was fed after 21 d in milk (DIM). Measures of hoof discoloration, hemorrhage, and/or ulcer formation were done at about 45 d before calving, and near 28 and 70 DIM. Rumenocentesis was performed 14 d before calving and at 8, 22, and 70 DIM. Hoof scores among treatments were similar at 28 DIM. The low NE(L), high NE(L) group had less desirable hoof scores than high NE(L), high NE(L), or low NE(L), low NE(L) groups from 55 to 75 DIM. Rumen pH did not differ by treatment before calving. The lowest postpartum rumen pH was significantly lower and rates of ruminal acidosis (pH < or = 5.8) at 8 and 22 DIM were higher for groups fed high NE(L) after calving. No direct relationship between low postpartum rumen pH and hoof scores on individual cows was found. Low NE(L) before calving and high NE(L) right after calving may increase risk of subclinical laminitis if not carefully managed.

Effects of whole cottonseed diet and recombinant bovine somatotropin on ovarian follicles in lactating dairy cows.

The effects of whole cottonseed (WCS) in the diet and the administration of bovine somatotropin (bST) on ovarian follicular dynamics and plasma progesterone (P4) concentrations were examined in cows during a period of synchronized follicular growth. Lactating Holstein cows (n = 28) were randomly assigned to treatments in a 2 x 2 factorial arrangement. Diets consisted of WCS (15% of dry matter) or no WCS, and bST at a dose of 0 or 208 mg/14 d. Dietary treatments began within 24 h of calving and bST treatments began within 7 d postpartum. Cows received GnRH at 65 +/- 3 d postpartum (d 0), PGF2alpha, (d 7), a second dose of GnRH (d 9), and were inseminated 16 h later (d 10). Ovarian changes were monitored daily by ultrasonography from d 0 to 9. On d 9,93% of cows had a preovulatory follicle and 86% ovulated. For Class 2 (6 to 9 mm) follicles, a diet x bST interaction was detected, with bST stimulating Class 2 follicles in cows fed WCS, but not in cows on the control diet. Neither diet nor bST affected numbers of Class 1 (2 to 5 mm) or Class 3 (> or = 10 mm) follicles or sizes of the subordinate and dominant follicles. During the luteal phase of the cycle, lactating cows fed WCS tended to have elevated concentrations of plasma P4, whereas bST was without effect. Plasma concentrations of high-density lipoprotein cholesterol were increased in cows fed WCS. Number and diameter of corpora lutea did not differ among treatments.

Effects of gossypol from cottonseed on hematological responses and plasma alpha-tocopherol concentration of dairy cows.

The effects of feeding whole cottonseed (WCS) and bovine somatotropin (bST) administration on hematological responses and plasma alpha-tocopherol concentrations of lactating dairy cattle were examined. After parturition, multi and primiparous Holstein cows (n = 159) were assigned randomly to a 2 x 2 factorial arrangement of treatments consisting of (0 or 15% WCS and 0 or 208 mg of bST injected every 2 wk starting within 7 d after calving. Blood samples were collected from a subset group of 64 cows at 14, 28, 42, and 56 d postpartum. Blood was collected from all cows (n = 159) at 75, 96 and 120 d postpartum. Blood samples were analyzed for alpha-tocopherol and total and (+)- and (-)-gossypol in plasma. Erythrocyte osmotic fragility, hemoglobin and hematocrit also were determined in blood. The mean concentrations of alpha-Tocopherol, total, and (+)- and (-)-gossypol were higher in cows fed WCS regardless of bST administration and plateaued by d 75 postpartum. Hematocrit and hemoglobin concentrations were not affected by treatments. Erythrocyte osmotic fragility was higher in cows fed WCS, but the increase was attenuated when bST was injected (diet x bST interaction). No clinical signs of gossypol toxicity were observed in the cows consuming the WCS.

Effects of prepartum dry matter intake and forage percentage on postpartum performance of lactating dairy cows.

The objective of this research was to determine whether different dry matter intakes (DMI) or forage percentages prepartum would have an impact on postpartum performance. Multiparous Holstein cows (n = 41) received either high (H) or low (L) forage rations that were fed free choice (F) or restricted (R), i.e., HF, HR, LF, and LR. The L rations were higher in net energy of lactation and lower in neutral detergent fiber concentrations. After calving, all cows were fed the same ration ad libitum. Prepartum DMI were 8.0 for R versus 12.4 kg/d for F with LF greater than HF (14.1 vs. 10.7 kg/d). Prepartum treatments did not affect postpartum means for DMI, milk yield, milk protein percentage, body weight, body condition score, or plasma glucose concentrations (overall means 1 to 40 DIM were, respectively, 21.1 kg/d, 34.0 kg/d, 3.03%, 624 kg, 3.2, and 66 mg/dl). However, curves from 1 to 40 DIM showed that DMI and milk yield were slightly higher in early lactation in cows whose DMI had been restricted prepartum but mean milk fat percentage was lower (3.10 vs. 3.42%). Plasma NEFA were higher and insulin lower in H versus L before and after calving. High DMI prepartum, at best, showed no advantage over restricted feeding.

Interrelationships in lactating Holsteins of rectal and skin temperatures, milk yield and composition, dry matter intake, body weight, and feed efficiency in summer in Alabama.

Thirty-two lactating, multiparous Holstein cows were utilized in a 91-d experiment in Auburn, Alabama, during summer to determine whether rectal and skin temperatures and respiration rates are repeatable and interrelated and whether whole cottonseed or calcium salts of long-chain fatty acids (Megalac, Church & Dwight Co., Inc., Princeton, NJ) affected milk production or its constituents. Treatments were (I) control, (II) I plus 10.4% whole cottonseed, (III) I plus 2.6% Megalac, and (IV) I plus 5.2% whole cottonseed plus 1.3% Megalac. Data included 358 to 2644 measurements analyzed as a split-plot design of experiment. Only milk protein percentage and protein-to-fat ratio were significantly affected by dietary treatment. Milk protein percentage was depressed by dietary fat additions, especially by the combination of whole cottonseed and Megalac. Within lactation repeatabilities for milk, fat, protein, and SCM yields ranged from 0.44 to 0.66; two percentages and protein to fat ratio, 0.21 to 0.32; feed efficiency, 0.18; dry matter intake (DMI) and body weight, 0.98 and 0.84; rectal and skin temperatures and respiration rate, 0.001 to 0.055. Partial and simple correlations were similar in sign and magnitude. Noteworthy were partial correlations between milk yield and DMI, 0.367; milk yield and rectal temperature, -0.135; milkyield and respiration rate, 0.102. Skin temperature was unrelated to other variables. Respiration rate was correlated with DMI, 0.270. Results should help researchers designing future experiments involving these responses to predict the number of measures needed to detect differences.

Responses of lactating dairy cows to copper source, supplementation rate, and dietary antagonist (iron).

Forty-eight lactating Holstein cows were fed low-Cu diets with 500 mg of supplemental Fe/kg of dry matter (DM), a Cu antagonist, for a 30-d Cu-depletion period. After depletion, two Fe treatments (0 and 500 mg of Fe/kg of dietary DM) and five Cu treatments (2 x 5 factorial arrangement) were compared over 83 d. The Cu treatments were control (basal diet containing 8 mg of Cu/kg of DM) and either 15 or 30 mg of supplemental Cu/kg of dietary DM from either CuSO4 or Cu-lysine. Feeding 500 mg of supplemental Fe/kg of DM (in addition to basal dietary concentration of 140 mg Fe/kg) depressed liver Cu in the absence of Cu supplementation. Apparent Cu retention, estimated from Cu intake minus fecal Cu, was increased greatly by Cu supplementation immediately after the depletion period but declined to very low net retention by d 45 of the 83-d experiment. There were no differences detected between CuSO4 and Cu-lysine except a tendency over time for Cu-lysine to maintain higher plasma Cu, especially in the absence of the Fe antagonist.

Performance of dairy cattle fed citrus pulp or corn products as sources of neutral detergent-soluble carbohydrates.

The effects of modifying the dietary profile of neutral detergent-soluble carbohydrates (NDSC) on milk production and rumen fermentation were determined. Corn silage and alfalfa hay-based diets were formulated to contain 40% calculated NDSC supplied primarily by dried citrus pulp as a source of neutral detergent-soluble fiber (NDSF), or corn products as sources of starch. Diets were compared within cow with reversal experiments with two periods. In experiment 1, 11 multiparous Holstein cows including three ruminally cannulated animals were individually fed diets containing 23.6% citrus pulp (diet CPD) or 25.3% corn hominy (diet HD) on a dry matter basis. In experiment 2, 184 animals fed as two groups received diets containing 20.5% citrus pulp (diet CPD) or 19.5% cornmeal (diet CMD). Diets CPD provided more dietary NDSF and HD and CMD more starch. In experiment 1, cows fed HD had a greater milk protein percentage (+0.12%), and tended to yield more milk protein (0.08 kg/d) than cows fed CPD. Although ruminal H+ concentrations did not differ between diets, diet x time postfeeding interactions were significant. Ruminal organic acid concentrations did not differ between diets. In experiment 2, cows fed CMD yielded more milk (3.9 kg/d), 3.5% fat- and protein-corrected milk (2.6 kg/d), fat (0.05 kg/d), and protein (0.08 kg/d), whereas cows fed CPD produced greater concentrations of fat (+0.18%), and milk urea nitrogen (0.76 mg/dl). Modifying the proportions of NDSC in the diet can alter milk production and composition, the pattern of ruminal fermentation, and N utilization in dairy cows.

Effects of anaerobic digestion and additives to effluent or cattle feed on odor and odorant concentrations.

Odor intensity (5,437 observations), determined by human panelists (100 different panelists over the course of the experiment), and a number of chemical odorant concentrations were determined for manure-related samples (326) obtained from effluents from conventional stirred-tank reactor (CSTR) and fixed-film anaerobic digesters, effluents to which commercial additives or KMnO4 or H2O2 were added, and feces, urine, and mixed manure from cows fed a control or additive-containing diet. Mostly, samples were held in stoppered, Erlenmeyer flasks for 3 d at room temperature before evaluation by panelists and with chemical analyses, but shorter holding times also were tested. Anaerobic digestion reduced odor intensity linearly with increasing hydraulic retention time (HRT) up to 20 d; fixed-film digestion with 1.5- or 2.3-d HRT reduced odor intensity similarly to that observed with 10-d HRT in CSTR. Addition of commercial products and chemicals altered some odorant concentrations (e.g., ammonia) but did not reduce odor intensity; some products increased odor intensity. Addition of a commercial yeast-based product to a dairy cow diet had no detectable effect. The cow diet study showed that fresh urine and feces alone were less odorous than a mixed combination (manure). Fresh manure was less odorous than manure held for 3 d. Total phenol was the odorant most highly correlated with odor intensity. Individual and total volatile fatty acids also contributed. Ammonia did not seem to be a major contributor to odor in this data set.

Ruminant nutrition from an environmental perspective: factors affecting whole-farm nutrient balance.

Nutrient budgeting strategies focus primarily on recycling manure to land as fertilizer for crop production. Critical elements for determining environmental balance and accountability require knowledge of nutrients excreted, potential nutrient removal by plants, acceptable losses of nutrients within the manure management and crop production systems, and alternatives that permit export of nutrients off-farm, if necessary. Nutrient excretions are closely related to nutrient intake and can be predicted by subtracting predicted nutrients in food animal products exported from the farm from total nutrients consumed. Intensifying crop production with double- or triple-cropping often is necessary for high-density food animal production units to use manure without being forced to export manure or fertilizer coproducts to other farms. Most manures are P-rich relative to N largely because of 1) relatively large losses of volatilized NH3, most of it converted from urea in urine, 2) denitrification losses in soil under wet, anaerobic conditions, and 3) ability of many crops to luxury-consume much more N than P. Most soils bind P effectively and P usually is permitted to accumulate, allowing for budgets to be based on N. However, P budgeting may be required in regions where surface runoff of P contributes to algae growth and eutrophication of surface waters or where soil P increases to levels of concern. Research is needed to determine whether dietary P allowances can be lowered without detriment to animal production or health in order to lower P intake and improve N:P ratios in manure relative to fertilization needs.

Effects of varying forage types on milk production responses to whole cottonseed, tallow, and yeast.

Four forage treatments (45% corn silage, 33.75% corn silage plus 11.25% alfalfa hay, 11.25% bermudagrass hay, or 11.25% cottonseed hulls on a DM basis) were arranged factorially with no added fat, 12.5% whole cottonseed, or 2.5% tallow. Different diets were fed during three 28-d periods to 20 control Holstein cows and to 20 cows receiving yeast continuously in a split-plot design. Milk yield of cows fed cottonseed hulls with corn silage was 2.4 kg/d higher than with corn silage plus bermudagrass hay and .7 kg/d higher than with corn silage only or corn silage plus alfalfa hay. Whole cottonseed depressed milk yield by 1 kg/d. Cows fed yeast had increased DMI, and yeast interacted with forage so that more milk was produced by cows fed alfalfa diets. Yeast depressed milk protein percentage. Holstein cows in a commercial Florida dairy were fed no yeast or 10 g/d continuously for 60 d; milk fat percentage was greater (3.51 vs. 3.37%) with yeast. In summary, effects on milk and SCM were positive when cottonseed hulls were utilized with corn silage, negative with whole cottonseed, and neutral with supplemental tallow. Yeast effects on SCM, although not significant for either experiment, tended to be positive for both (mean +1.2 kg/d per cow).

Effects of variable sources of distillers dried grains plus solubles on milk yield and composition.

This study compared diets supplemented with distillers dried grains plus solubles originating from whiskey distilling with those from fuel alcohol production or soybean meal. Forty-eight cows in mid and early lactation were offered a different dietary treatment in each of three 28-d periods. Dietary design included three supplements at 14 or 18% CP of dietary DM, with or without blood meal. Additionally, a third, darker, fuel ethanol source was added at 14 and 18% CP without blood meal during period 3 to incorporate greater variation in quality of distillers grains. No detectable differences occurred in DMI or in any variables because of blood meal. Milk yield was higher when cows were fed diets at 18% rather than at 14% CP. Cows fed the two lighter distillers grains diets yielded .8 kg/d more milk than cows fed soybean meal diets, and cows fed whiskey distillers grains yielded 1.3 kg/d more SCM than cows fed diets with darkest distillers grains. Milk protein percentage was depressed when the darkest distillers grains were fed. Distillers dried grains plus solubles can provide an excellent substitute for soybean meal and corn in dairy cow diets.

Components of dairy manure management systems.

Dairy manure management systems should account for the fate of excreted nutrients that may be of environmental concern. Currently, regulatory oversight is directed primarily at the assurance of water quality; N is the most monitored element. Land application of manure at acceptable fertilizer levels to crops produced on the farm by hauling or by pumping flushed manure effluent through irrigation systems is the basis of most systems. Nutrient losses to surface and groundwaters can be avoided, and significant economic value can be obtained from manure as fertilizer if adequate crop production is possible. Dairies with insufficient crop production potential need affordable systems to concentrate manure nutrients, thereby reducing hauling costs and possibly producing a salable product. Precipitation of additional nutrients from flushed manures with sedimented solids may be possible. Composting of separated manure solids offers a possible method to stabilize solids for distribution, but, most often, solids separated from dairy manures are fibrous and low in fertility. Manure solids combined with wastes from other sources may have potential if a marketable product can be produced or if sufficient subsidy is received for processing supplementary wastes. Solutions to odor problems are needed. Energy generated from manure organic matter, via anaerobic digestion, reduces atmospheric emissions of methane and odorous compounds. Use of constructed wetlands or harvesting of photosynthetic biomass from wastewater has the potential to improve water quality, making extensive recycling possible.

Effects of undegradable protein and supplemental fat on milk yield and composition and physiological responses of cows.

Because some previous studies indicated that addition of dietary fat may delay milk yield response and that effects carry over after withdrawal, an objective of this reversal design with four 28-d periods was to estimate residual effects. Diets were fed 2 wk before period 1 to permit inclusion of pretreatment diet in the mathematical model and changed for each of 33 cows at the start of periods 1 through 3; period 4 treatments continued those for period 3. Diets were 50% corn silage supplemented to be 12% CP with soybean meal and urea; 15% CP with soybean meal, blood and soybean meals, or feather and soybean meals; and 18% CP with soybean meal or blood and soybean meals. Protein treatments were replicated in diets containing 2.0% Ca soaps of fatty acids. No carry-over effects were significant; however, yield increases from Ca soaps were not evident until wk 4. Diet CP had a positive linear effect on milk and SCM yields, BW, and blood urea N. Milk protein percentage was higher from soybean meal diets. Addition of dietary Ca soaps of fatty acids increased milk, protein, fat, and SCM yields. Milk protein percentage was depressed when Ca soaps of fatty acids were fed with blood meal but not with soybean meal. No positive responses were observed from increasing dietary undegradable protein with blood meal or feather meal.

Effects of concentration of dietary phosphorus on amount and route of excretion.

Objectives were to determine the effect of dietary concentration of P in DM on routes of excretion of P and to evaluate direct and indirect measures of calculating DM digestibility and P excretion. Twelve lactating Holstein cows were fed 20 kg of DM containing .41% P daily for 4 wk and then were assigned randomly to one of three diets: low (.30%), medium (.41%), or high (.56%) in P for 9 wk. Total collections of excreta (feces and urine) and milk were made during wk 4, 7, 10, and 13. At wk 4, cows excreted 88.2% of P consumed daily: 68.6% of excreted P in feces, 1.0% in urine, and 30.3% secreted in milk. Cows assigned to the low P diet decreased intake by 26.8% and excretion of P in feces by 22.7% in wk 13 compared with wk 4, whereas cows fed the high P diet increased intake by 36.5% and excretion of P in feces by 48.6%. Digestibility of DM was 62.6% when calculated from total collection of feces but only 55.7 or 56.5% when estimated indirectly using Cr or acid detergent lignin as indigestible markers. Apparent excretion of P was less than that estimated using either of the marker techniques (49.7 vs. 59.1 and 58.1 +/- .7 g/d of P) because digestibility of DM was underestimated. A prediction equation was developed for P excretion based on P intake and milk production.

Responses of lactating dairy cows to protected fats or whole cottonseed in low or high forage diets.

Thirteen treatments to compare effects of dietary fat on milk yield and composition were control, 15% whole cottonseed, and 2 and 4% Ca-tallowate factorially distributed in low forage (35% corn silage DM) with 14 or 18% CP and high forage (66% corn silage) diets with an additional diet of 8% Ca-tallowate. Different treatments were fed to 36 cows in each of three 28-d periods. Feeding 2 and 4% Ca-tallowate improved milk yield with high forage, although DM intake was slightly depressed; compared with 4% Ca-tallowate, DM intake and milk yield were depressed by 8% Ca-tallowate. Across all diets, whole cottonseed depressed DM intake and milk yield more than when nearly equal fat came from Ca-tallowate (4%). Calcium-tallowate depressed milk fat percentage linearly. Milk fat from cows fed whole cottonseed or Ca-tallowate contained unsaturated fatty acids (mostly C18:1) and lesser quantities of short-chain fatty acids. In a subsequent experiment, Ca-tallowate depressed milk fat percentage, whereas Megalac (calcium salts of fatty acids from palm oil) did not. In a field study, one trial with 210 cows in midlactation showed no effect on milk yield and composition from .54 kg of Megalac/d for 60 d, nor was there any effect detected with 121 cows in early lactation from feeding of .45 kg of Megalac/d for 90 d.

Dose response of dairy cows to ammonium salts of volatile fatty acids.

In previous studies ammonium salts of a mixture of isobutyrate, 2-methylbutyrate, isovalerate, and valerate were fed in a corn silage, corn, corn gluten meal, and urea diet to Holstein cows throughout lactation to define the optimum level of ammonium salts of milk production. The objective of this work was to conduct another dose response study using other forage and protein sources and to determine the effects of decreasing VFA intakes as lactation advanced. The concentrate portion of the diet contained 0, .4, .8, 1.2, or 1.6% ammonium salts of VFA. The forage to concentrate ratio was 50:50, 60:40, and 70:30 for the first, middle, and last third of lactation, respectively. The study was conducted at four university locations using 191 Holstein cows. Feeds used included corn silage, alfalfa silage or hay, corn, soybean meal, minerals, and vitamins. Treatment x location interactions were significant for milk yield during early lactation. During mid- and late lactation, supplemental VFA (.8%) improved milk and protein yield. Milk composition was not greatly affected by feeding VFA. In mid-lactation, cows fed .8% ammonium salts of VFA ate more feed than did controls. Feed efficiencies were similar among groups throughout the experiment. Cows fed VFA tended to gain less BW during lactation than did controls. Health and reproduction were not different among groups.

Dietary interaction of cane molasses with source of roughage: intake and lactation effects.

Effects of cane molasses at 0, 4, and 8% of DM in complete mixed diets were evaluated when molasses was fed to lactating dairy cows with cottonseed hulls, alfalfa haylage, or both combined. Thirty-six mature Holstein cows from mid to late lactation were used in a partially balanced incomplete block design with three 28-d periods. Variables measured were DM intake, milk yield, and composition. With cottonseed hull diets (30% of DM), molasses improved milk yield, milk fat percentage, solids-corrected milk, and feed efficiency. Dry matter intake was not affected by molasses. With alfalfa haylage diets (35% of DM), 8% molasses depressed actual milk yield and solids-corrected milk, DM intake, milk fat percentage, milk protein percentage, and feed efficiency. Milk fat percentage was increased with 4% molasses. With 65% alfalfa haylage diets, most variables measured were unaffected by molasses; however, with 8% molasses, DM intake increased and milk protein percentage decreased. In diets with both roughages combined, molasses did not affect any variable measured; however, these diets gave highest solids-corrected milk yields. Results show clearly that molasses effects depend on percentage molasses and type and amount of roughage in the diet.

Comparison of different methods of expressing dietary protein for lactating dairy cows.

Data were from Holstein cows from 20 experiments at the University of Florida (1688 cow-period observations). Objectives were to compare milk responses to increasing dietary percent or daily intake of CP, estimated undegradable CP, and estimated metabolizable protein from Burroughs and Chalupa equations and to determine if higher producing cows (26.8 kg milk/d) responded differently to increasing dietary protein percent or intake than do lower producing cows (18.9 kg milk/d). The mathematical model included experiment, cow-within-experiment, period, body weight, and source of roughage. Intake of protein (kg/d) had a greater effect (cubic polynomial) on milk yield than protein percent of DM since CP, undegraded protein, Chalupa metabolizable protein, and Burroughs metabolizable protein intakes explained 17.2, 20.9, 23.5, and 24.1% of residual variation in milk yield compared with .6, 2.1, 1.7, and 2.1%, for percents of DM. High producing cows responded more to increasing protein intake than did low producing cows. Respective protein intake variables explained 20.6, 23.7, 30.5, and 31.2% of residual variation in milk yield in high production group compared with 17.2, 23.1, 20.6, and 20.6% in low production group.

Effects of citrus molasses distillers solubles and molasses on rumen parameters and lactation.

Effects of dietary citrus molasses distillers solubles (0, 6, 12, and 18% of DM) on diet digestibility and ruminal parameters were studied with four fistulated Holstein cows fed each diet in Latin square sequence. Diets were 25% cottonseed hulls with solubles substituted for corn. Dry matter and organic matter digestibilities were increased curvilinearly with peak at 6%. Crude protein digestibility was depressed linearly and ADF curvilinearly with added solubles. Ruminal acetic acid proportion increased linearly and propionic acid decreased curvilinearly. Change in butyric acid was small with 0, 6, and 12% solubles but it increased dramatically with 18%. In a 36-cow (107 cow-period) lactation experiment with corn silage-based and cottonseed hull-based diets (0, 3, 6, and 9% solubles) milk yield increased; the diet containing 6% solubles gave highest production. We compared cane molasses (3 and 6%), liquid hemicellulose extract (3%, Masonex), and liquid lignin sulfonate (3%, Flambeau) added to cottonseed hull diets. Linear increases in milk yield and FCM were obtained with cane molasses; Flambeau and Masonex effects on production were not different from control. With diets and amounts used in these experiments, citrus molasses solubles and cane molasses each at up to 6% of DM nutritionally were superior to corn.

Effects of neutral detergent fiber and roughage source on dry matter intake and milk yield and composition of dairy cows.

Data were from 20 experiments that utilized early to midlactation Holstein cows fed complete mixed diets or fed at constant forage:concentrate ratios. Within-cow diet comparisons (1688 cow-periods) were analyzed by least squares analysis of variance; mathematical model included experiment, cow in experiment, period, body weight, and source of roughage. Objectives were to determine relationships between neutral detergent fiber content of diet and milk yield and dry matter intake. Roughages and number of cow-periods were: sugarcane bagasse/silage (507), cottonseed hulls (504), corn silage (268), ground corrugated boxes (170), alfalfa/peanut hay (132), and others (107). Dry matter intake and estimated net energy intake had linear effects on milk yield and explained 21.6 and 24.0% of its residual variation; milk yield had curvilinear (quadratic) effect and explained 22.4% of dry matter intake residual variation. Interaction between neutral detergent fiber and source of roughage on milk yield, 4% fat-corrected milk, and dry matter intake resulted in reductions of 5.6, 5.6, and 13% in residual variations. Results suggest neutral detergent (% of dry matter) has greater effect on dry matter intake than on milk yield and its use in formulating diets for dairy cows will be within roughage source.