Partial Mixed Ration Research Articles

Quality and safety of hemp meal as a protein supplement for nonlactating dairy cows

Hemp seed meal may be a suitable protein supplement for dairy cows, but its quality and safety as a dairy cow feed has not yet been fully investigated. As a result, dry matter intake (DMI), rumen fermentation, blood metabolites, total-tract digestibility, and concentrations of cannabinoids in blood plasma, urine, muscle, and adipose tissues were compared among nonlactating Holstein dairy cows receiving a basal partial mixed ration that was supplemented with either 10.2% dry matter (DM) hemp meal (HM treatment), 13.5% DM canola meal (CM treatment), or 6.25% DM hemp meal and 6.16% DM canola meal (HC treatment). Diets were formulated to be isoenergetic and isonitrogenous. Six nonlactating, nonpregnant Holstein cows were used in a repeated 3 × 3 Latin square design trial with three 3-wk experimental periods. The first 2 weeks of each served as adaptation. Sample and data collection occurred during the third week of each period. Neither the partial mixed ration nor canola meal contain cannabidiol (CBD), cannabidiolic acid (CBDA), d9-tetrahydrocannabinol (THC), or tetrahydrocannabinolic acid A (THCA-A). However, the hemp meal contained 3.0, 4.4, 0, and 0.1 μg/g DM of CBD, CBDA, THC, and THCA-A, respectively. Treatment did not affect DMI, pH, concentrations of volatile fatty acids or ammonia in the rumen, total-tract digestibilities of DM and crude protein, or blood plasma concentrations of glucose, urea, β-hydroxybutyrate, and nonesterified fatty acids. Hence, based on these metabolites, treatment did not affect the nutritional status of the cows. However, the total-tract neutral detergent fiber digestibility of the CM treatment (43%) was higher than that of the HM treatment (38%). No cannabinoids were detected in blood plasma, rumen fluid, and urine. Cannabinoids were also not detected in kidney, liver, urine, muscle, or adipose tissues at the end of the experiment when cows had undergone all treatments. Feces from all treatments did not contain detectable concentrations of THC or THCA-A, but feces of cows on the HC treatment contained 0.42 and 0.40 μg/g DM of CBD and CBDA, respectively. Feces of cows on the HM treatment contained 0.68 and 0.67 μg/g DM of CBD and CBDA, respectively. This indicated that most ingested CBD and CBDA were not absorbed but instead were excreted in the feces. Our data show dietary inclusion rates of up to 10.2% of DM. We find that hemp meal is a high-quality and safe protein supplement for nonlactating dairy cows.

Comparing dehulled hemp meal and canola meal as a protein supplement for lactating dairy cows

Effects of replacing canola meal with dehulled hemp meal in the diet of lactating dairy cows on the dry matter intake (DMI), milk production, milk fatty acid profile, blood metabolites, total-tract nutrient digestibility, and transfer of cannabinoids were determined in 12 lactating, nonpregnant Holstein cows. These cows were used in a 3 × 3 Latin square design with three 3-wk experimental periods consisting of 2 wk of adaptation and 1 wk of sampling. Cows received basal partial mixed rations supplemented with either 15% dry matter (DM) canola meal (CM15), 15% DM dehulled hemp meal (HM15), or 7.5% DM dehulled hemp meal and 7.5% DM canola meal (CM7.5HM7.5). Diets were formulated to be isoenergetic and isonitrogenous, but the HM15 and CM7.5HM7.5 diets contained, on average 1.2 percentage units more crude protein (CP) that the CM15 diet. The CP of the dehulled hemp meal contained less soluble protein than that of canola meal. Hence, the intake of soluble protein did not differ among diets. Canola meal contained less crude fat than hemp seed meal (3.46% vs. 8.25% DM). The lipid fraction of canola meal fat contained more oleic acid (C18:1 cis-9; 47.3 vs. 14.9 g/100 g of fatty acids, FA) and vaccenic acid (18:1 cis-11; 13.7 vs. 1.2 g/100 g of FA) and less linoleic acid (C18:2n-6; 21.9 vs. 55.7 g/100 g of FA) and α linolenic acid (C18:3n-3; 3.2 vs. 8.9 g/100 g of FA) than the lipid fraction of hemp seed meal. The hemp seed meal contained 4.9 µg/g cannabidiol, 5.1 µg/g cannabidiolic acid, and 0.1 µg/g tertahydroxycannabinolic acid A. Treatments did not differ in DMI, yields of milk, milk protein and milk fat, total-tract neutral detergent fiber digestibility, and blood plasma concentrations of β-hydroxybutyrate and nonesterified FA. Apparent total-tract DM digestibility was lowest in the HM15 treatment, whereas the CP digestibility and the concentrations of urea in blood, urine, and milk were lowest in the CM15 treatment. Cannabinoids were not detected in urine, milk, and blood plasma. Replacing canola meal with hemp seed meal increased milk fat contents of polyunsaturated fatty acids (PUFA), which were 3.42, 3.90, and 4.25 g/100 g of FA for the CM15, CM7.5HM7.5, and HM15 treatments, respectively. Especially, the milk fat contents of 18:2n-6 (1.99 vs. 1.56 g/100 g FA) and 18:3n-3 (0.31 vs. 0.43 g/100 g FA) were increased by hemp meal feeding. Especially, the milk fat contents of 18:2n-6 (1.99 vs. 1.56 g/100 g FA) and 18:3n-3 (0.31 vs. 0.43 g/100 g FA) were increased by hemp meal feeding. Our data show that hemp seed meal is a suitable and safe replacement for canola meal as a feed for lactating dairy cows and that this replacement increases CP digestibility and urea in urine, milk, and blood plasma, as well the PUFA content of milk fat.

Evaluation of two commercially available rumen buffers derived from calcified seaweed for grazing dairy cows: Pilot trial in commercial farms

Calcified seaweed (CS) based products have been proposed as an alternative ruminal pH buffer to sodium bicarbonate. It has been reported that magnesium can aid in ruminal pH control too, especially those natural marine forms. We assessed the rumen buffer capacity and milk production and milk composition of two CS: Acid Buf (AB) compared with M12 (a natural marine magnesium enriched CS) on grazing dairy cows in a replicated Latin Square design involving 2 farms with the dairy herd in good sanitary and health status, 2 supplements and 4 measurements periods of one month each. Holstein Friesian dairy cows fed with a partial mixed ration (PMR) were supplemented for 30-d periods with either AB or M12. Total milk production and milk composition were measured in each farm, and five cows in each herd had rumen boluses for the monitoring of ruminal pH, allowing us to identify and monitor total subacute ruminal acidosis (SARA) events (i.e., = 2 h with pH < 5.8). The average pH during the experimental period was 2% greater (p < 0.05) and the number of SARA events per cow was lower (p = 0.007) for cows supplemented with M12 compared to AB. If only the cows that developed SARA events were considered, M12 showed a trend (p = 0.068) to reduce the number of SARA events and their duration compared to those cows supplemented with AB. Milk production and composition were similar between both rumen buffers at all periods.

Impact of varying levels of pasture allowance on the nutritional quality and functionality of milk throughout lactation

The objective of this study was to examine the impact of increasing proportions of grazed pasture in the diet on the composition, quality, and functionality of bovine milk across a full lactation. Fifty-four spring-calving cows were randomly assigned to 1 of 3 groups (n = 18), blocked on the basis of mean calving date (February 15, 2020 ± 0.8 d), pre-experimental daily milk yield (24.70 ± 3.70 kg), milk solids yield (2.30 ± 0.27 kg), lactation number (3.10 ± 0.13), and economic breeding index (182 ± 19). Raw milk samples were obtained weekly from each group between March and November 2020. Group 1 (GRS) consumed perennial ryegrass and was supplemented with 5% concentrates (dry matter basis); group 2 was maintained indoors and consumed a total mixed ration (TMR) diet consisting of maize silage, grass silage, and concentrates; and group 3 consumed a partial mixed ration diet (PMR), rotating between perennial ryegrass during the day and indoor TMR feeding at night. Raw milk samples consisted of a pooled morning and evening milking and were analyzed for gross composition, free amino acids, fatty acid composition, heat coagulation time, color, fat globule size, and pH. The TMR milks had a significantly higher total solids, lactose, protein, and whey protein as a proportion of protein content compared with both GRS and PMR milks. The GRS milks demonstrated a significantly lower somatic cell count (SCC), but a significantly higher pH and b*-value than both TMR and PMR milks. The PMR milks exhibited significantly lower total solids and fat content, but also demonstrated significantly higher SCC and total free amino acid content compared with GRS and TMR. Partial least squares discriminant analysis of fatty acid profiles displayed a distinct separation between GRS and TMR samples, while PMR displayed an overlap between both GRS and TMR groupings. Variable importance in projection analysis identified conjugated linoleic acid cis-9,trans-11, C18:2n-6 cis, C18:3n-3, C11:0, and C18:2n-6 trans as the largest contributors to the variation between the diets. Milk fats derived from GRS diets exhibited the highest proportion of unsaturated fats and higher unsaturation, health-promoting, and desaturase indices. The lowest proportions of saturated fats and the lowest atherogenic index were also exhibited by GRS-derived milk fats. This work highlights the positive influence of grass-fed milk for human consumption through its more nutritionally beneficial fatty acid profile, despite the highest milk solid percentages derived from TMR feeding systems. Furthermore, this study demonstrates the proportional response of previously highlighted biomarkers of pasture feeding to the proportion of pasture in the cow's diet.

Effect of pre- and postpartum supplementation of a pure glycerol product to dairy cows on feed intake, metabolic markers, and milk yield and components

The objective of this study was to quantify the effects of supplementing transition dairy cows with a low inclusion dry glycerol product in the pre- and postpartum periods on feed intake, metabolic markers, and milk yield and components. Multiparous Holstein dairy cows (n = 60) were enrolled in a 2-by-2 factorial design study. Starting 21 d before expected parturition, cows individually received a dry cow diet with (1) 250 g/d glycerol product supplementation [66% pure glycerol (United States Pharmacopeia grade); GLY], or (2) no supplementation (CON) mixed to their total mixed ration. After parturition, cows, again, were individually assigned to either GLY, or (2) no supplementation (CON) to their partial mixed ration for the first 21 d in milk (DIM). Cows were milked by an automated milking system and offered a target of 5.4 kg DM/d pellet (23% of target total dry matter intake, DMI) in the automated milking system and followed for 42 d into lactation. Blood samples were collected 6.3 ± 3.47 d before calving for all blood measures and 3, 7, 10, and 14 DIM for analysis of glucose and β-hydroxybutyrate, as well as 3 and 7 DIM for nonesterified fatty acids (NEFA) and haptoglobin. Initial dry cow body weight (BW), calf birth weight, previous 305-d milk, and month of parturition were used as covariates in the statistical model. Cows supplemented with GLY prepartum lost less BW and consumed more DMI pre- and postpartum, as well as had lower postpartum blood β-hydroxybutyrate and NEFA concentrations compared with those fed the CON treatment prepartum. Cows supplemented with GLY postpartum had lesser DMI in the first 42 DIM than cows fed CON postpartum, but also had reduced blood NEFA concentrations, odds of a high haptoglobin test, odds of a low blood glucose test, and lesser preformed fatty acid concentrations and yields in their milk. Cows supplemented glycerol both pre- and postpartum lost the least total BW from -21 to 21 DIM. No treatment effects were detected for milk yield; however, cows receiving GLY postpartum had lower milk fat. Overall, glycerol supplementation during the transition period, particularly during the 21 d before calving, was associated with markers of improved metabolic status.

Including 8 hours of access to alfalfa in 1 or 2 grazing sessions in dairy cows fed a partial mixed ration: Effects on intake, behavior, digestion, and milk production and composition

The aim of this study was to evaluate the inclusion of alfalfa grazing during 8 h continuous or partitioned in 2 separated sessions of 4 h after each milking, on nutrient intake, digestibility, ruminal fermentation, feeding behavior, milk production, milk composition, and milk fatty acid profile, in late-lactation cows fed a partial mixed ration (PMR). Twelve dairy cows (193 ± 83 d in milk, 584 ± 71 kg of body weight) were housed in individual outdoor pens and assigned to treatments according to a 3 × 3 Latin square design replicated 4 times. The treatments were as follows: (1) control (T0), cows were fed a total mixed ration (TMR) provided ad libitum 20.0% crude protein (CP), 32.2% neutral detergent fiber (NDF); (2) fed a diet combining a PMR which had the same ingredient composition as the TMR (60% of ad libitum intake) + 1 session of 8 h of pasture (T8), continuous grazing alfalfa (Medicago sativa; 20.6% CP, 35.8% NDF) after the p.m. milking; and (3) PMR (60% of ad libitum intake) + 2 daily sessions of 4 h of access to pasture after each milking (T4+4). The experiment lasted 57 d and was divided into 3 periods of 19 d each. The first 12 d of each period was used for diet adaptation, and the last 7 d was used for data collection. No differences among treatments were observed for any of the productive variables, feeding efficiency, or purine derivatives excretion. Cows in T0 had greater intake and apparent digestibility of dry matter, organic matter, and nonfibrous carbohydrates compared with T4+4 and T8. Compared with T0, alfalfa grazing increased the concentration of C18:1 trans-11 and decreased those of C16:0 and C17:0 in milk fat. Cows in T4+4 consumed 1.1 more kg DM/d of alfalfa and N provided by alfalfa in the diet was 3 percentage points higher compared with T8 cows (266 vs. 229 g/d, respectively). In addition, T4+4 cows had a greater daily range of ruminal pH than T8 (0.73 vs. 0.93), and the highest concentrations of NH3-N were recorded during the a.m. grazing session while in T8 cows it occurred during the night. In conclusion, including 8 h of alfalfa grazing in T8 and T4+4 treatments allowed the substitution between 35.8 and 38.7% of the total dry matter intake (DMI) of a PMR (with a similar CP concentration to alfalfa) for pasture, maintaining milk solids production and increasing the C18:1 trans-11 of milk fat compared with a TMR in mid late-lactation cows. In an herbage plus PMR diet, splitting the 1 continuous grazing session of 8 h into 2 sessions of 4 h increased the proportion of energy and N provided by alfalfa pasture and reduced PMR intake, without modifying the total nutrient intake or productive performance of cows.

Effectiveness of precision feeding in reducing N excretion in dairy cattle

Two periods enrolling 56 (milk yield 36.2 ± 7.91 kg/d) and 58 (milk yield 32.4 ± 4.99 kg/d) grouped-fed dairy cows were performed to evaluate nutrient adjustment and N emissions of a precision feeding strategy. Pens blocked by parity were randomly assigned to a conventional (CONV) or to a precision feeding scheme (PREC) for a 21-d period. The CONV group was offered a total mixed ration (TMR, 6.82 and 6.65 MJ of NEl/kg of DM, in period 1 and 2, respectively, and 165 g of CP/kg of DM in both periods; whereas PREC cows were fed a partial mixed ration (PMR, 6.65 and 6.40 MJ of NEl/kg of DM, 135 and 137 g of CP/kg of DM, in period 1 and 2, respectively) and a concentrate feed supplemented twice daily in the milking parlour, which contained different quantities of soybean meal, corn meal, and wheat middling’s according to estimated nutritional needs of each cow above those supplied by the consumption of PMR. Individual daily nutritional needs and nutrients consumed from the PMR were calculated using a 10-d rolling average of performance data (milk yield and concentration of its components, and BW daily recorded in both periods). A N balance using urine and fecal spot sampling during the last 3 d of the study was performed in period 1, and stored manure gaseous emissions (ammonia, methane, nitrous oxide, and carbon dioxide) were measured for 2 wk in period 2. After 2 wk of adaptation to the diet, 82 cows homogeneously distributed in 4 DIM categories: early DIM (< 81), mid-early DIM (81−150), mid-late DIM (151−220), late DIM (> 220) were used to assess how energy and protein requirements were adjusted using both feeding system. Dairy cows in both feeding systems were energetically overfed, and CONV cows tended to be more CP overfed in mid-late and late DIM cows than PREC fed cows. Total daily N urine excretion, and milk N urea concentration were greater in CONV than in PREC cows. There were no differences in ammonia and nitrous oxide emissions from the manure storage between PREC and CONV cows; however, methane and carbon dioxide emissions from manure increased by 55% and 15%, respectively in PREC fed cows. Precision feeding system based on preceding average daily milk yield and composition can reduce N excretion without affecting short-term milking performance but increasing C gaseous emissions from manure.

Evaluation of 3 northwest European seaweed species on enteric methane production and lactational performance of Holstein-Friesian dairy cows

Seaweeds have been studied for their ability to reduce enteric methane emissions of ruminants when fed as a feed supplement. In vivo research with dairy cattle is mainly limited to the seaweed species Ascophyllum nodosum and Asparagopsis taxiformis, whereas in vitro gas production research covers a broader range of brown, red, and green seaweed species from different regions. The objective of the present study was to determine the effect of Chondrus crispus (Rhodophyta), Saccharina latissima (Phaeophyta), and Fucus serratus (Phaeophyta), 3 common northwest European seaweeds, on enteric methane production and lactational performance of dairy cattle. Sixty-four Holstein-Friesian dairy cattle (16 primiparous, 48 multiparous) averaging (mean ± standard deviation) 91 ± 22.6 d in milk and 35.4 ± 8.13 kg/d fat- and protein-corrected milk yield (FPCM) were randomly assigned to 1 of 4 treatments in a randomized complete block design. Cows were fed a partial mixed ration [54.2% grass silage, 20.8% corn silage, and 25.0% concentrate; dry matter (DM) basis] with additional concentrate bait in the milking parlor and the GreenFeed system (C-Lock Inc.). The 4 treatments consisted of a control diet without seaweed supplement (CON), or CON supplemented with 150 g/d (fresh weight of dried seaweed) of either C. crispus (CC), S. latissima (SL), or a 50/50 mix (DM basis) of F. serratus and S. latissima. Milk yield (28.7 vs. 27.5 kg/d, respectively), fat- and protein-corrected milk (FPCM) yield (31.4 vs. 30.2 kg/d, respectively), milk lactose content (4.57 vs. 4.52%, respectively), and lactose yield (1,308 vs. 1,246 g/d, respectively) increased for SL compared with CON. Milk protein content was lower for SL compared with the other treatments. Milk fat and protein contents; yields of fat, protein, lactose, and FPCM; feed efficiency; milk nitrogen efficiency; and somatic cell count did not differ between CON and the other treatments. Depending on week of experiment, milk urea content was higher for SL compared with CON and CC. No effects were observed of the treatments compared with CON for DM intake, number of visits to the GreenFeed, or gas emission (production, yield, or intensity) of CO2, CH4, and H2. In conclusion, the seaweeds evaluated did not decrease enteric CH4 emissions and did not negatively affect feed intake and lactational performance of dairy cattle. Milk yield, FPCM yield, milk lactose content, and lactose yield increased, and milk protein content decreased, with S. latissima.

When the measurement affects the object – Impact of a multi-part head/neck mounted wearable device on dairy cow behaviour, health and productivity

Wearable technology is increasingly used in both dairy research and commercial dairy farming. Assessment of how such wearables affect cows is of major importance to rule out reductions in welfare and productivity that would hamper commercial implementation. Furthermore, if devices intended to measure behaviour affect behaviour, data can no longer be extrapolated to a larger (unequipped) population, hampering their use as research tools. Lack of published research on this topic may cause an underestimation of effects on cows and research findings. We assessed the effects of a head/neck mounted wearable intended to capture methane and measure activity on dairy cow behaviour, health and productivity. The device consisted of a nose-piece covering the nostrils, held in place by a halter and a 4 kg neck-rig (31 × 19 × 23 cm at the widest points). We performed a 2 × 3-week cross-over trial involving 44 cows. Whereas many variables were not found to be affected, the wearable significantly (P < 0.05) affected bald spots (2.3-fold increase), social grooming (initiated: 41% decrease, received: 34% decrease) and drinking time (10% increase). Furthermore, milk yield and lactose content were significantly decreased, and partial mixed ration intake tended to be decreased (P < 0.10), but all three to a minor extent (<2% decrease). During the initial 6 h only, the wearable significantly increased transitions (standing up and lying down) and tended to increase the probability of a lowered head. During the first week only, the wearable significantly affected step counts (14% increase). During the last (third) week only it affected displacements with physical contact in the feeder area (initiated: 29% increase, P < 0.10, received: 34% increase, P < 0.05). This study showed that wearable technology can affect several parameters of dairy cow welfare. Whilst some effects were minor or short-lived, others were larger and persisted or increased throughout the 3-week deployment phase. This suggests that a habituation period of approximately one week should be observed before collecting data with the wearable. In addition, further product development would be advisable to reduce skin abrasions and improve its suitability for long-term application.

Effects of raw and fermented rapeseed cake on ruminal fermentation, methane emission, and milk production in lactating dairy cows

The objective of this study was to evaluate the effects of replacing raw rapeseed cake (RC) with fermented rapeseed cake (FRC) in the diet of dairy cows on methane (CH4) production, ruminal fermentation, and milk production, composition, and fatty acid composition. The Hohenheim gas test (exp. 1) was initially used to evaluate RC and FRC as substrates. Following batch fermentation, an in vitro study (exp. 2) was performed to assess the effects of replacing RC with FRC at 28.75, 57.5, 86.25, and 115 g/kg (FRC25, FRC50, FRC75, and FRC100) in the total mixed rations (TMR). Based on the in vitro results, the control TMR (115 g/kg dry matter (DM) of RC; CONRC) and experimental TMR (115 g/kg DM of FRC; FRC100) were chosen for an in vivo assessment. In exp. 3, four ruminally cannulated cows were used in a replicated 2 (group) × 2 (period) crossover design and fed the TMR ad libitum. In exp. 4, twenty multiparous Polish Holstein-Friesian cows in their mid-lactation (148 ± 26 d in milk) were used in a completely randomized design. The cows were fed a partial mixed ration without the RC and FRC, and the RC and FRC were supplied in a concentrate feeder at 2.65 kg/d/cow. The FRC100 markedly decreased CH4 production by 12% and archaeal population without adversely affecting nutrient digestibility. The molar proportion of propionate was increased, and the molar proportion of acetate and butyrate and acetate to propionate ratio were decreased by FRC100. No significant effects on milk production or composition, except an increase in milk urea concentration, were observed in cows fed FRC100. Milk C18:2 cis-9, trans-11 concentration was greater, and n-6 to n-3 fatty acid ratio was lower for FRC100 than CONRC. In-situ ruminal degradation of RC and FRC were explored using in-sacco techniques (exp. 5). The potential degradation and effective degradability of the DM, organic matter, and crude protein were significantly higher for FRC than RC. These results suggested that FRC could mitigate enteric CH4 production by decreasing archaeal abundances without adversely affecting milk production and ruminal fermentation in lactating cows.

Nutrient utilization and ingestive behavior by lambs fed a partial mixed ration consisting of different carbohydrate sources combined with fresh alfalfa

The objective of the current study was to evaluate the nutrient utilization by lambs fed partial mixed ration (PMR) containing either cereal grain or fibrous by-products as an energy source complemented with fresh alfalfa. Eighteen male Corriedale × Ile-de France lambs (32.2 ± 1.82 kg body weight and 4 months old) fitted with permanent rumen catheters were individually housed in metabolism cages and randomly assigned to the treatments (diets): FF, fresh alfalfa ad libitum; PMR-C, PMR containing cereal grains plus fresh alfalfa or PMR-F, PMR containing fibrous by-products plus fresh alfalfa. The amount of PMR offered corresponded to 75% of the potential total dry matter intake of lambs, in two equal meals daily (i.e. morning and afternoon) whereas fresh alfalfa was offered ad libitum from 10:00 to 18:00 h The inclusion of PMR, independently of the energy source, increased the nutrient intake and digestibility of lambs and reduced daily eating time. The ruminal fluid of lambs fed either PMR showed lower pH, higher propionate and butyrate concentration, and lower NH3 concentration compared to lambs fed only alfalfa (P < 0.01). Lambs fed PMR-F showed lower digestibility of N compounds and ruminal ammonia concentration compared to lambs fed PMR-C (P < 0.01). We concluded that offering PMR combined with fresh alfalfa to lambs had positive effects on nutrient intake, regardless of whether the energy source in PMR was starch or fibers.

Examining feed preference of different pellet formulations for application to automated milking systems

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.

Performance of Dairy Cows Supplemented with By-Pass Fat under Heat Stress Conditions

The objective of this study was to determine the effect of supplementation with a protected fat source on the productive response, metabolic environment and physiological indicators in Holstein cows under heat stress conditions during a 12-week experimental period. Thirty Holstein cows were distributed in 15 blocks by parity (2.0 ± 1.1), days in milk (182 ± 80) and milk production (29.4 ± 5.7 kg·day-1) at the beginning of the trial and randomly assigned within each block to the following treatments (diets): SPF: supplementation with protected fat or WPF: without supplementation with protected fat. All the cows were kept in a dry-lot where they were given a partial mixed ration (PMR) ad libitum while in the milking parlor they received individual supplementation depending on the treatment. The SPF diet contained 4.0 kg·day-1 concentrate in pellet form + 0.6 kg·day-1 ground corn grain + 0.7 kg·day-1 protected fat, while the WPF diet was similar to that offered in SPF, but the protected fat was isoenergetically replaced by ground corn grain. The fat supplement contained fats of animal and vegetable origin and microencapsulation was used for its preparation. Total dry matter and metabolic energy intakes were similar (p > 0.05) between treatments. Fat corrected milk (4% FCM) production was higher (p = 0.04), while energy corrected milk and fat productions tended (p = 0.06) to be higher in cows from the SPF group, without effects (p > 0.05) on the rest of the milk production and composition parameters. These results could be attributed to an improvement in the efficiency of the use of the energy consumed. Protected fat supplementation neither modified the metabolic profile, nor reduced the respiratory rate and body temperature of heat-stressed cows. Future research is needed to explain this latter result.

Effects of fermentative quality of corn silage on lactation, blood metabolites, and rumen fermentation in dairy cows.

We investigated the effect of fermentation quality of corn silage on dry matter intake (DMI), milk yield, ruminal fermentation, methane (CH4 ) emissions, and plasma metabolites in lactating cows. Six lactating Holstein cows were used in a 2 × 2 crossover design with two dietary treatments containing high quality corn silage with lower pH (high group) or low quality corn silage with higher pH (low group). The cows were fed partial mixed ration (PMR containing 50%DM of each corn silage) ad libitum plus 0.7 kg/day of concentrates at milking. The DMI of cows in the low group (24.8 kg/day) tended to be lower (p< 0.10) than that in the high group (26.8 kg/day). The dietary treatment did not affect milk yield or milk fat, protein, or lactose concentrations. The ruminal acetic acid proportion of the low group was significantly higher (p< 0.05) than that of the high group. The CH4 emission per DMI of the low group tended to be higher (p< 0.10) than that of the high group. The plasma concentration of the total cholesterol (TCHO) and the activity of aspartate aminotransferase and alanine aminotransferase of the low group were significantly higher than those of the high group.

Variability in Enteric Methane Emissions among Dairy Cows during Lactation

The aim of this study was to investigate variability in enteric CH4 emission rate and emissions per unit of milk across lactations among dairy cows on commercial farms in the UK. A total of 105,701 CH4 spot measurements were obtained from 2206 mostly Holstein-Friesian cows on 18 dairy farms using robotic milking stations. Eleven farms fed a partial mixed ration (PMR) and 7 farms fed a PMR with grazing. Methane concentrations (ppm) were measured using an infrared CH4 analyser at 1s intervals in breath samples taken during milking. Signal processing was used to detect CH4 eructation peaks, with maximum peak amplitude being used to derive CH4 emission rate (g/min) during each milking. A multiple-experiment meta-analysis model was used to assess effects of farm, week of lactation, parity, diet, and dry matter intake (DMI) on average CH4 emissions (expressed in g/min and g/kg milk) per individual cow. Estimated mean enteric CH4 emissions across the 18 farms was 0.38 (s.e. 0.01) g/min, ranging from 0.2 to 0.6 g/min, and 25.6 (s.e. 0.5) g/kg milk, ranging from 15 to 42 g/kg milk. Estimated dry matter intake was positively correlated with emission rate, which was higher in grazing cows, and negatively correlated with emissions per kg milk and was most significant in PMR-fed cows. Mean CH4 emission rate increased over the first 9 weeks of lactation and then was steady until week 70. Older cows were associated with lower emissions per minute and per kg milk. Rank correlation for CH4 emissions among weeks of lactation was generally high. We conclude that CH4 emissions appear to change across and within lactations, but ranking of a herd remains consistent, which is useful for obtaining CH4 spot measurements.

Effects of Sugar Beet Silage, High-Moisture Corn, and Corn Silage Feed Supplementation on the Performance of Dairy Cows with Restricted Daily Access to Pasture.

Simple SummarySeasonal variations in herbage growth rate and nutrient composition result in low herbage intake which is insufficient to meet the nutritional requirements of cows and limits milk production. The main opportunities for increasing milk production per cow and per ha are a careful pasture management to ensure adequate herbage high-quality and strategic low-cost and high-energy feed supplementation. Supplementation strategies include different combinations of level, type, and processing of supplemental feeds. This study evaluates the effect of supplementation with sugar beet silage, corn silage, or high-moisture corn (HMC) on dairy performance, rumen, and plasma metabolites in dairy cows under conditions of restricted grazing in spring. We found that the supplementation with sugar beet silage allowed milk production, live weight, and fat concentration similar to corn silage and HMC, but with a lower concentration of milk protein than HMC. Results suggest that sugar beet silage can be used as an alternative supplement for high-producing dairy cows under conditions of restricted grazing in the current experiment.A study was undertaken to assess the effect of supplementation with sugar beet silage, corn silage, or high-moisture corn on dairy performance, rumen, and plasma metabolites in dairy cows under conditions of restricted grazing in spring. Eighteen multiparous Holstein Friesian cows, stratified for milk yield (39.4 kg/day ± 3.00), days of lactation (67.0 days ± 22.5), live weight (584 kg ± 38.0), and number of calves (5.0 ± 1.5), were allocated in a replicated 3 × 3 Latin square design. Treatments were as follows: SBS (10 kg DM of permanent pasture, 7 kg DM of sugar beet silage, 4 kg DM of concentrate, 0.3 kg DM of pasture silage, 0.21 kg of mineral supplement); corn silage (10 kg DM of permanent pasture, 7 kg DM of corn silage, 4 kg DM of concentrate, 0.3 kg DM of pasture silage, 0.21 kg of mineral supplement), and HMC (10 kg DM of permanent pasture, 5 kg DM of high-moisture corn, 4.5 kg DM of concentrate, 1.2 kg DM of pasture silage, 0.21 kg of mineral supplement). Pasture was offered rotationally from 9 a.m. to 4 p.m. Between afternoon and morning milking, the cows were housed receiving a partial mixed ration and water ad libitum. The effect of treatments on milk production, milk composition, body weight, rumen function, and blood parameters were analyzed using a linear–mixed model. Pasture dry matter intake (DMI) was lower in SBS than CS (p < 0.05) and similar to HMC, but total DMI was higher in HMC than SBS (p < 0.05) and similar to CS. Milk production for treatments (32.6, 31.7, and 33.4 kg/cow/day for SBS, CS, and HMC, respectively), live weight, and fat concentration were not modified by treatments, but milk protein concentration was lower for SBS compared with HMC (p < 0.05) and similar to CS. B-hydroxybutyrate, cholesterol, and albumin were not different among treatments (p > 0.05), while urea was higher in SBS, medium in CS silage, and lower in HMC (p < 0.001). Ruminal pH and the total VFA concentrations were not modified by treatments (p > 0.05), which averaged 6.45 and 102.03 mmol/L, respectively. However, an interaction was observed for total VFA concentration between treatment and sampling time (p < 0.05), showing that HMC produced more VFA at 10:00 p.m. compared with the other treatments. To conclude, the supplementation with sugar beet silage allowed a milk response and composition similar to corn silage and HMC, but with a lower concentration of milk protein than HMC. In addition, sugar beet silage can be used as an alternative supplement for high-producing dairy cows with restricted access to grazing during spring.

Effects of concentrate allowance and individual dairy cow personality traits on behavior and production of dairy cows milked in a free-traffic automated milking system

The primary objective of this study was to determine whether the level of concentrate allowance in an automated milking system (AMS) affects the feed intake, eating behavior, milking activity, and performance of lactating dairy cows. The secondary objective of this study was to describe how the response to concentrate allocation, specifically in feeding and milking behavior, varies with cow personality traits. Fifteen Holstein cows were used in a crossover design with two 28-d periods, each including 14 d of adaptation and 14 d of data collection. The cows were housed in a freestall pen with free-traffic access to the AMS. Treatments consisted of a basal partial mixed ration (PMR) common to both treatment groups, with a concentrate allowance (on dry matter basis) of (1) 3.0 kg/d in the AMS (L-AMS) or (2) 6.0 kg/d in the AMS (H-AMS). Between the 2 treatment periods, each cow was assessed for personality traits using a combined arena test consisting of exposure to a novel environment, novel object, and novel human. Principal component analysis of behaviors observed during the novel environment and object tests revealed 3 factors (interpreted as active, social, and alert-curious) that together explained 76% of the variance, whereas principal component analysis of the novel human test revealed 2 factors (interpreted as active-vocal and fearful of novel humans) that together explained 77% of the variance. When on the H-AMS treatment, PMR dry matter intake (DMI) was less (24.5 vs. 26.0 kg/d) and AMS concentrate delivery was greater (5.9 vs. 3.1 kg/d), as per design. Consequently, total DMI was greater on the H-AMS treatment (30.4 vs. 29.1 kg/d). When on the H-AMS treatment, cows who were more alert-curious consumed more PMR, whereas cows who were more fearful of the novel human were less likely to receive the maximum amount of AMS concentrate available, limiting their total DMI and increasing the day-to-day variability of that intake. Although this was a preliminary study, these data suggest an association between dairy cow personality traits and how cows respond to increased AMS concentrate allowance.

Changing the grazing session from morning to afternoon or including tannins in the diet was effective in decreasing the urinary nitrogen of dairy cows fed a total mixed ration and herbage

Our aim was to evaluate whether increasing soluble carbohydrates in the herbage by changing the time of the grazing session or including Acacia mearnsii tannin in the diet would affect intake, digestion, N partitioning, and productive performance of dairy cows fed a diet combining ryegrass herbage with partial total mixed ration (PMR). We hypothesized that both strategies could reduce the concentration of NH3-N in the rumen, reducing urinary N excretion. Nine Holstein cows were used in a triplicate 3 × 3 Latin square experiment with 3 experimental periods of 22 d. The cows were fed a fixed amount of PMR [60% of the predicted individual dry matter intake (DMI)], and an unrestricted amount of herbage in 1 grazing session of 5 h/d. The treatments were (1) morning grazing session and afternoon PMR meal (AM); (2) morning PMR meal and afternoon grazing session (PM); and (3) morning grazing session and afternoon PMR meal supplemented with 15.0 g of tannins/kg of PMR dry matter (TAN). Milk production was not affected by treatments. Although the protein concentration was lower for TAN than for PM, no differences were detected for the yield of any component between treatments. The concentration of individual or grouped fatty acids in milk fat was not affected by treatments, except for 16:1 cis-9 and Δ9-desaturase ratios 14:1/14:0 and 16:1/16:0, which were lower for TAN. Treatments did not affect total DMI, but PM tended to increase herbage DMI and reduce dry matter and crude protein digestibilities. Treatments did not affect cow eating and ruminating behavior except for the proportion of time spent eating PMR, which was higher for PM and TAN. Although no relevant effects of treatments on ruminal fermentation, purine derivatives excretion in urine, or N excretion in milk were detected, both PM and TAN decreased the total N excreted in urine by an average of 8% compared with AM. In conclusion, changing the grazing session from the morning to the afternoon and including tannins in the diet were effective in decreasing the excretion of urinary N but did not change the productive performance of dairy cows fed PMR and ryegrass herbage.

Rumination Behavior and Its Association with Milk Yield and Composition of Dairy Cows Fed Partial Mixed Ration Based on Corn Silage

Rumination Behavior and Its Association with Milk Yield and Composition of Dairy Cows Fed Partial Mixed Ration Based on Corn Silage

Effects of supplementing a Saccharomyces cerevisiae fermentation product on the prevention and control of digital dermatitis in lactating dairy cows

The aim of the study was to evaluate the effects of supplementing a Saccharomyces cerevisiae fermentation product (SCFP, NutriTek, Diamond V) on the prevention and control of digital dermatitis (DD) in lactating dairy cows. A blinded randomized, controlled field study on a commercial robot-milking farm was performed for 5 mo using the first 2.5 mo for the base phase and the last 2.5 mo for the test phase. A total of 968 lactating cows were enrolled in the trial distributed over 4 pens. The SCFP and control supplements were fed in their respective partial mixed ration. GoPro (https://gopro.com) images of the cows’ hind feet in the milking robots were scored to identify the presence of DD using an M-stage DD classification system. Pen-level analysis revealed no statistically significant differences in M-stage groups between the control and SCFP group during the base and test phases of the study. Cow level analysis indicated that the relative risk for having M2M2P lesions (ulcerated/active) versus having M0M4H lesions (healthy/contained) in the control group during the test phase was 1.8 times greater compared with the SCFP group. The transition from M0M4H to M2M2P lesions occurred more rapidly in the control group compared with the SCFP group. The supplementation of SCFP warrants further research as a potential DD prevention and control strategy in dairy cattle.