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ABSTRACT: Some forages require significant amounts of water to grow, causing the dairy industry to be dependent on a limited resource. Feeding crop residues and feed coproducts in dairy rations may represent opportunities when alfalfa is not readily available, and may reduce the industry's use of water. A study using indirect calorimetry and 12 multiparous lactating Jersey cows (BW = 447.5 ± 43.7 kg; DIM = 71 ± 11 d, mean ± SD) was conducted to determine the effect of feeding dried distillers grains and solubles (DDGS) and straw in replacement of alfalfa hay on milk production and energy utilization. A triplicated 4 × 4 Latin square design was used to evaluate the replacement of alfalfa hay with a coproduct mixture (COP) of wheat straw and DDGS. Animals were blocked by milk yield and randomly assigned to 1 of 4 experimental treatments as follows (proportions on a DM basis): a control diet (CON) containing 18.2% of alfalfa hay, a low-coproduct diet (LCOP) that contained 8.1% COP, a medium-coproduct diet (MCOP) that contained 16.3% COP, and a high-coproduct diet (HCOP) that contained 24.3% COP. No differences were observed for daily DMI or milk yield (mean ± SEM), 19.5 kg ± 0.60 and 29.6 kg ± 0.91, respectively. A quadratic tendency was observed, where increasing inclusion of COP up to 16.3% maintained ECM and milk fat yield but decreased these when animals were fed 24.3% COP. Total methane production decreased linearly from 429.4 to 345.0 ± 22.8 L/d from CON to HCOP diets, respectively. The digestibility of CP increased linearly from 64.0% to 70.4% ± 0.95%, and N balance increased linearly from 43.3 to 90.7 ± 15.0 g/d in animals consuming CON to HCOP diets. Total time spent ruminating was lowest in animals consuming the HCOP diet. A linear increasing tendency in digestible and metabolizable energy of 2.92 to 3.02 ± 0.041 Mcal/kg and 2.58 to 2.70 ± 0.047 Mcal/kg was observed in animals consuming CON to HCOP. The proportion of metabolizable energy from digestible energy tended to linearly increase from 88.3 to 89.4 ± 0.454 when COP was added to the diet. Results of this study indicate that alfalfa hay with a mixture of straw and DDGS can maintain milk production and DMI, but the partial or full replacement of alfalfa with the COP mixture may result in differences in energy utilization, in part driven by effects on CH4 reduction.

Diets formulated for dairy cattle are designed to supply nutrients, but rations delivered to the animal may deviate from original formulations, resulting in implications for milk production, composition, and even pregnancy rate. The objective of this study was to evaluate retrospective feed mixing records collected from 8 commercial dairy farms over 52 wk. Farms ranged from 2,982 to 29,783 animals, producing 31.8 ± 5.93 (±SD) kg of milk with 4.14 ± 0.461% fat and 3.26 ± 0.218% protein. Data collected included daily TMR nutrient deviation, calculated as diet nutrient content minus the observed divided by the formulated diet concentrations of CP, fat, NDF, and starch. Data were analyzed with fixed effects of time (modeled as 28-d periods) and days of positive nutrient deviation in fat, CP, NDF, and starch with each nutrient alone and in combination with the other nutrients, random effects of herd, and repeated measure of time within herd. The nutrient deviation by farm averaged (±SD) 1.68 ± 2.655, 2.28 ± 4.473, 1.75 ± 2.621, and 1.47 ± 2.147% for CP, fat, NDF, and starch, respectively. Days of positive nutrient deviation per period averaged (±SD) 25.5 ± 3.47, 25.5 ± 3.72, 25.6 ± 3.49, and 25.9 ± 2.61, respectively. Dry matter intake (DMI; 17.2 ± 1.78 kg/d) decreased with increasing positive deviation days in starch (−0.0483 ± 0.01265) and increased with increasing positive deviation days in CP (0.0211 ± 0.00942). Milk yield (31.4 ± 2.50 kg/d) increased with positive deviation days in starch (0.0486 ± 0.02110) and decreased with increased positive deviation days in NDF (−0.0298 ± 0.02202). Finally, pregnancy rate (21.7 ± 4.34) increased with increasing positive deviation days in fat (0.385 ± 0.1635) and decreased with increasing positive deviation days in CP (−0.420 ± 0.1879). For these models, period significantly affected milk yield but was not observed to affect pregnancy rate and DMI. Results suggest farm and nutrient type were significant sources of variation, and overall, farms overfeed nutrients CP, fat, NDF, and starch 92% of the days of a 28-d period.

ABSTRACT: Animals vary in the way in which they use energy due to diet, genetics, and management. Energy consumed by the animal supports milk production, but considerable variation among animals in energy utilization is thought to exist. The study objective was to estimate the among-animal variance in energy utilization in data collected from Jersey cows using indirect calorimetry. Individual animal-period data from 15 studies (n = 560) were used. The dataset included 115 animals from 44 to 410 DIM producing 11.5 to 39.1 kg/d of milk. On average, the 63 treatments in the dataset ranged 14.8% to 19.5% CP, 21.4% to 43.0% NDF, 16.2% to 33.3% starch, and 2.21% to 6.44% crude fat. Data were analyzed with the GLIMMIX procedure of SAS (9.4) with random effects of cow, treatment nested within period, square, and experiment. The percentage of among-animal, dietary treatment, and experimental variance was calculated as the variance associated with each fraction divided by the sum of variance from animal, dietary treatment, experiment, and residual, which was considered the total variance. The percentage of among-animal variance was characterized as high or low when the value was greater than or less than the mean value of 29.2%. Among-animal variance explained approximately 29.3% to 42.5% of the total variance in DMI, gross energy (GE), digestible energy (DE), ME, and NEL in megacalories per day. When energetic components of feces, urine, heat, and lactation in megacalories per day were expressed per unit of DMI, the among-animal variance decreased by 20.4, 4.82, 9.55, and 3.80 percentage units, respectively. However, among-animal variance explained 4.80 and 5.02 percentage units more of the total variation for methane energy and tissue energy in megacalories per day when expressed per unit of DMI. Variance in energetic efficiencies of DE/GE, ME/GE, and ME/DE were explained to a lesser extent by among-animal variance (averaging 17.8 ± 1.95%). The among-animal contribution to total variance in milk energy was 28.8%. Milk energy was a large proportion of the energy efficiency calculation, which included milk energy plus corrected tissue energy over net energy intake, which likely contributed to the 22.2% of total among-animal variance in energy efficiency. Results indicate that among-animal variance explains a large proportion of the total variation in DMI. This contributes to the variance observed for energy fractions as well as energy components when expressed in megacalories per day. Variation in energetic loss associated with methane was primarily explained by differences among animals and was increased when expressed per unit of DMI, highlighting the role of inherent animal differences in these losses.

ABSTRACT: Research in a variety of species including cattle has suggested energy required for maintenance may be affected by body condition. The objective of this study was to use indirect calorimetry and total fecal and urine collections to estimate maintenance energy and fasting heat production (FHP) of cows differing in BCS. Twelve multiparous nonpregnant and nonlactating Jersey cows were randomly assigned to one of 2 treatment groups. To construct these groups, cows were fed 2 different TMR in a preexperimental period for 84 d resulting in a BCS of >5 (HiBCS) and a BCS

Two taste preference experiments were conducted with the same 8 multiparous lactating Jersey cattle (100 ± 7.1 DIM, 30.5 ± 4 0.06 kg of milk yield, 18.8 ± 2.52 kg of DMI in experiment 1; and 215 ± 7.1 DIM, 27.6 ± 3.98 kg of milk yield, 19.6 ± 3.03 kg of DMI in experiment 2). In experiment 1, 4 pellets were formulated and manufactured into 4.0-mm pellets. These were as follows: 45.7% alfalfa meal, 45.7% corn grain, and 8.57% wheat middlings (ALFC); 72.3% corn grain, 18.5% wheat middlings, and 9.25% dried distillers grains and solubles (ENG); a pellet containing 100% dehydrated alfalfa meal (DALF); and a pellet containing a mixture of concentrate ingredients (GMIX; 43.1% corn grain, 26.3% dried distillers grains and solubles, 13.8% wheat middlings, 7.10% dry molasses, 3.18% soybean meal, 0.93% corn oil, and 5.6% minor constituents). Cows were offered 0.50 kg of pellets in a randomized arrangement within the feed bunk. Feed preference was ranked from 1 to 4 with 1 being the most preferred and 4 the least. The resulting preference rankings were averaged (± SE) resulting in a highest (closest to 1) to lowest (furthest from 1) ranking as follows of ALFC (1.38 ± 0.164), ENG (2.13 ± 0.327), GMIX (2.88 ± 0.375), and DALF (3.13 ± 0.350). The probabilities of first choice were 70.6 ± 0.55% ALFC, 16.5 ± 0.46% ENG, 5.50 ± 0.475% DALF, and 7.48 ± 0.455% GMIX. A Z-test was conducted to determine the percentage a treatment would be chosen first differed from the value of no preference at 25%; ALFC and DALF differed from the mean value, whereas no difference was observed for ENG and GMIX. The most preferred pellet (ALFC) was used in a second study and compared against 3 other treatments in which different flavoring agents were added. In this study, 4 pellets were manufactured with ALFC: 45.7% alfalfa meal, 45.7% corn grain, 6.76% wheat middlings, and 1.81% oregano leaf (ALFCO); 45.7% alfalfa meal, 45.7% corn grain, 8.22% wheat middlings, 0.10% melon flavoring, and 0.25% BitterOff (ALFCM); and 45.7% alfalfa meal, 45.7% corn grain, 8.47% wheat middlings, and 0.10% licorice flavoring (ALFCL). The resulting preference rankings were averaged resulting in a highest to lowest ranking as follows: ALFC (1.25 ± 0.164), ALFCO (2.38 ± 0.263), ALFCM (2.63 ± 0.375), and ALFCL (3.25 ± 0.164). The probabilities of first choice were 81.9 ± 0.65% ALFC, 8.49 ± 0.46% ALFCO, 6.50 ± 0.481% ALFCM, and 3.12 ± 0.491% ALFCL. Of the pellet choices, ALFC and ALFCL differed from the mean value of no choice, whereas no difference was observed for ALFCO and ALFCM. Mixtures of corn grain and dehydrated alfalfa meal bound by wheat middlings may serve as a feeding strategy that is preferred by the animals and may be an effective reward to cows entering an automated milk system, and we were unable to improve preference by adding flavoring agents.

ABSTRACT: Advancing technologies of the corn dry-milling ethanol production process includes the mechanical separation of fiber-containing particles from a portion of plant- and yeast-based nitrogenous particles. The resulting high-protein processed corn coproduct (HPCoP) contains approximately 52% crude protein (CP), 36% neutral detergent fiber (NDF), 6.4% total fatty acids (TFA). The objective of this experiment was to examine the effects of replacing nonenzymatically browned soybean meal with the HPCoP on dry matter intake (DMI), energy and N utilization, and milk production of lactating Jersey cows. Twelve multiparous Jersey cows were used in a triplicated 4 × 4 Latin square design consisting of four 28-d periods. Cows were blocked by milk yield and assigned randomly to 1 of 4 treatment diets that contained HPCoP (dry matter [DM] basis) at (1) 0%; (2) 2.6%; (3) 5.4%; and (4) 8.0%. Diets were formulated to be isonitrogenous and thus replace nonenzymatically browned soybean meal with HPCoP in the concentrate mix, while forage inclusion remained the same across diets. Increasing the concentration of HPCoP had no effect on DMI (mean ± SE; 19.9 ± 0.62 kg/d), but tended to linearly increase milk yield (27.8, 28.5, 29.8, and 29.0 ± 1.00 kg/d). Although no difference was observed in the concentration of milk protein with increasing inclusion of HPCoP (3.40% ± 0.057%), the concentration of fat linearly increased with the inclusion of HPCoP (5.05%, 5.19%, 5.15%, 5.47% ± 0.18%). No differences were observed in the digestibility of DM, NDF, CP, TFA, and gross energy averaging 66.6% ± 0.68%, 49.0% ± 1.03%, 66.1% ± 0.82%, 73.6% ± 1.73%, 66.3% ± 0.72%, respectively, with increasing HPCoP inclusion. The concentration of dietary gross energy linearly increased with increasing concentrations of HPCoP (4.25, 4.26, 4.28, and 4.31 ± 0.01 Mcal/kg), but no difference was observed in digestible energy and metabolizable energy (ME) across treatments averaging 2.83 ± 0.033 and 2.53 ± 0.043 Mcal/kg, respectively. Concentration of dietary net energy for lactation (NEL) tended to increase with increasing HPCoP (1.61, 1.72, 1.74, 1.72 ± 0.054 Mcal/kg) with the ratio of NEL:ME increasing linearly with increasing HPCoP inclusion (0.648, 0.676, 0.687, 0.677 ± 0.0124). Results of this study suggest that inclusion of the HPCoP can replace nonenzymatically browned soybean meal and support normal milk production.

Four lactating, ruminally cannulated Jersey cows, (mean ± standard deviation) 264 ± 54.2 d in milk and 484 ± 24.1 kg of body weight, were arranged in a 4 × 4 Latin square design to measure the effects of abomasal infusion of choline chloride with or without dl-Met on milk and plasma choline metabolites and plasma AA in cows fed a Met-deficient diet. Cows were randomly assigned to 1 of 4 experimental treatments: (1) control; no supplemental Met or choline (CON), (2) 13 g/d of choline ion delivered via abomasal infusion (CHO), (3) 13 g/d of Met delivered via abomasal infusion (MET), and (4) 13 g/d of choline and 13 g/d of Met delivered via abomasal infusion (CHO + MET). Cows received the same basal diet throughout the experiment, which was formulated to be deficient in Met (−5.0 g of Met using the NASEM, 2021, model). Periods were 7 d in length with d 1 to 2 serving as a wash-out period and cows being infused on d 3 to 7. Milk samples were collected twice daily on d 5 to 7 and were analyzed for fat, true protein, lactose, and choline metabolites including betaine, phosphocholine, and free choline using hydrophilic interaction liquid chromatography-tandem mass spectrometry. Blood samples were collected via venipuncture of the coccygeal vein at 1100, 1300, and 1500 h on d 7 of each period and were analyzed for free AA as well as choline metabolites. Plasma Met increased in response to Met infusion and an interaction with choline and Met infusion was observed in the plasma concentration of branched-chain AA. Cows receiving choline exhibited the greatest Cho yield in milk. Milk phosphocholine yield tended to be highest when both choline and Met were infused.

Starch and NDF are usually assumed to contain the same concentration of gross energy (GE), but NDF is more variable in chemical composition and varies more in the extent of digestion. The variable chemical composition of NDF may have direct implications on dairy nutrition models that predict dietary GE and use this estimate for also predicting digestible energy. For example, when NDF is enriched in lignin and protein, the concentration of GE would increase, whereas NDF enriched in ash would have the opposite effect. Current nutritional models, such as the NASEM (2021) and CNCPS (6.55), assume a GE coefficient of 4.20 Mcal/kg for NDF. This study aimed to determine the heat of combustion of NDF and to consider if it is a contributing factor to the variance in digestible energy. To do so, NDF residues were isolated from 9 feed and 8 fecal samples and then combusted. Approximately 0.20 g of NDF residues from 16 feeds (corn silage, n = 2; grass hay, n = 2; alfalfa hay, n = 2; wheat straw, n = 1; cottonseed hulls, n = 1; soyhulls, n = 1; distillers dried grains with solubles, n = 1; and total mixed ration, n = 6) and 34 fecal samples were collected. A bomb calorimeter (Parr 6400 Calorimeter, Parr Instrument Company) was used to determine concentration of GE in each NDF residue sample. The GE concentration of feed NDF was observed to be 4.03 ± 0.245 Mcal/kg, which was similar to that of fecal NDF (3.94 ± 0.245 Mcal/kg). The lack of difference between feed and fecal NDF GE implies that digested NDF is of a similar GE concentration as total feed NDF and that current nutritional models are validated in their current approach in predicting digestible energy from NDF. However, our observed estimate of GE in NDF is lower than what is assumed and across feed types varied from 3.85 to 4.19 Mcal/kg.

Feed is often offered to a cow in the milking unit of an automated milking system. This offering provides nutrients but also acts as a reward to the cow for entering the unit. To complement the partial total mixed ration and to enable handling, flow, and delivery within this mechanized system, this offering is usually a mix of feeds that are combined and manufactured into a feed pellet. The objective of this experiment was to compare 4 different pelleting formulation strategies and measure the effects of feed preference in lactating Jersey cattle. To test the objective, a taste preference experiment was conducted with 8 multiparous lactating Jersey cattle (289 ± 25.3 d in milk, 26.0 ± 2.45 kg of milk yield, 19.36 ± 1.29 kg of dry matter intake). Four formulation strategies were tested including (1) a pellet containing feeds commonly included in the concentrate mixture of a total mixed ration, including 43.1% corn grain, 26.3% dried distillers grains, 3.18% soybean meal, and 5.6% vitamin and mineral premix (CMIX), (2) a pellet of dry corn gluten feed (CGF), (3) a pellet including feedstuffs that are considered to be highly palatable (53.2% wheat middling, 15.7% dried corn distillers grains and solubles, 15.2% cane molasses, and 1.81% oregano (FLVR), and (4) a high-energy pellet (ENG) consisting of 61% corn grain and 26.2% wheat middlings. Cows were offered 0.50 kg of each in a randomized arrangement within the feed bunk for 1 h or until the feed was fully consumed. According to the procedure, cows were offered all 4 treatments for the first 4 d, then the most preferred feed for each cow was removed, and the remaining 3 feeds were offered for 3 d. The process was repeated for the last 2 d. Feed preference was ranked from 1 to 4 with 1 being the most preferred and 4 the least. The resulting preference ranking was CGF (1.25 ± 0.463), FLVR (2.5 ± 0.926), CMIX (2.88 ± 0.835), and ENG (3.13 ± 0.991). These results were subsequently examined utilizing the Plackett-Luce analysis to examine the probability animals would choose a given pellet first based on the current data set. The analysis determined probabilities of first choice as 78.6 ± 0.601% CGF, 9.38 ± 0.438% FLVR, 4.94 ± 0.453% ENG, and 7.11 ± 0.439% CMIX. A Z-test was also conducted to determine if the percentage a treatment will be chosen first differed from the mean value of no preference at 25%. Corn gluten feed and ENG differed from the mean value while no difference was observed for FLVR and CMIX. Results suggest that animals exhibit a high degree of preference for CGF pellets and that this preference is greater than pellets containing other feed ingredients. Alternatively, cows appeared to exhibit the lowest preference for a high-energy pellet containing mostly corn and wheat middlings.

ABSTRACT: A simulation study was conducted to examine accuracy of estimating daily O2 consumption, CO2 and CH4 emissions, and heat production (HP) using a spot sampling technique and to determine optimal spot sampling frequency (FQ). Data were obtained from 3 experiments where daily O2 consumption, emissions of CO2 and CH4, and HP were measured using indirect calorimetry (respiration chamber or headbox system). Experiment 1 used 8 beef heifers (ad libitum feeding; gaseous exchanges measured every 30 min over 3 d in respiration chambers); Experiment 2 used 56 lactating Holstein-Friesian cows (restricted feeding; gaseous exchanges measured every 12 min over 3 d in respiration chambers); Experiment 3 used 12 lactating Jersey cows (ad libitum feeding; gaseous exchanges measured every hour for 1 d using headbox style chambers). Within experiment, averages of all measurements (FQALL) and averages of measurements selected at time points with 12, 8, 6, or 4 spot sampling FQ (i.e., sampling every 2, 3, 4, and 6 h in a 24-h cycle, respectively; FQ12, FQ8, FQ6, and FQ4, respectively) were compared. Within study a mixed model was used to compare gaseous exchanges and HP among FQALL, FQ12, FQ8, FQ6, and FQ4, and an interaction of dietary treatment by FQ was examined. A regression model was used to evaluate accuracy of spot sampling within study [i.e., FQALL (observed) vs. FQ12, FQ8, FQ6, or FQ4 (estimated)]. No interaction of diet by FQ was observed for any variables except for CH4 production in experiment 1. No FQ effect was observed for gaseous exchanges and HP except in experiment 2 where CO2 production was less (5,411 vs. 5,563 L/d) for FQ4 compared with FQALL, FQ12, and FQ8. A regression analysis between FQALL and each FQ within study showed that slopes and intercepts became farther from 1 and 0, respectively, for almost all variables as FQ decreased. Most variables for FQ12 and FQ8 had root mean square prediction error (RMSPE) less than 10% of the mean and concordance correlation coefficient (CCC) greater than 0.80, and RMSPE increased and CCC decreased as FQ decreased. When a regression analysis was conducted with combined data from the 3 experiments (mixed model with study as a random effect), results agreed with those from the analysis for the individual studies. Prediction errors increased and CCC decreased as FQ decreased. Generally, all the estimates from FQ12, FQ8, FQ6, and FQ4 had RMSPE less than 10% of the means and CCC greater than 0.90 except for FQ6 and FQ4 for O2 consumption and CH4 production. In conclusion, the spot sampling simulation with 3 indirect calorimetry experiments indicated that FQ of at least 8 samples (every 3 h in a 24-h cycle) was required to estimate daily O2 consumption, CO2 and CH4 production, and HP and to detect changes in those in response to dietary treatments. This sampling FQ may be considered when using techniques that measure spot gas exchanges such as the GreenFeed and face mask systems.

Hydrolyzed feather meal (HFM) is a feedstuff high in rumen undegraded protein (RUP) that can be used as an effective source of metabolizable protein for dairy cattle. Because the production process may vary, the rumen degradability and intestinal digestibility of HFM may also vary. Additionally, some processes may incorporate additional blood into the final product to result in feather meal with poultry blood. To determine the rumen degradability and intestinal digestibility of these products, several laboratory assays can be used; the common assays are the mobile bag (MOB), modified three-step (MTS), and Ross (ROS) assays. Although all 3 assays determine RUP digestibility, they vary in whether they are performed in situ, in vitro, or both. The objective of this study was to evaluate the ruminal degradability and intestinal digestibility of HFM originating from processes that differ in their inclusion of blood, and to compare the MOB, MTS, and ROS assays. Ten samples of HFM, which were identified by the suppliers as HFM with little blood (n = 5) and with more blood (n = 5), were spot-sampled, collected from 10 production plants across the United States, and subjected to all 3 assays. Assay type had an effect on RUP, total-tract crude protein (CP) digestibility, and the amount of RUP digested. A significant effect was observed on RDP and RUP concentrations for blood inclusion; no effect was detected for total-tract CP digestibility. We found no difference in RUP digestibility for assay or blood inclusion. There was also no interaction of the effect of assay or blood inclusion. Results suggest that even though there are differences in chemical composition in HFM associated with the inclusion of blood, such as ash and crude fat, few if any differences are observed in intestinal digestion of protein. Although the assays varied in their estimates of rumen undegraded protein, MOB and MTS yielded the most similar values. However, all 3 assays resulted in similar estimates of RUP digestibility.