Partial Mixed Ration Research Articles

Chewing and Drinking Activity during Transition Period and Lactation in Dairy Cows Fed Partial Mixed Rations.

Simple SummaryIt is common to feed cows varying levels of forage fibre in the time span before calving to lactation. The resulting changes in chewing time may help to evaluate if diets have adequate fibre content. Using rumination-halters to measure the chewing activities in dairy cows, we found diminished rumination and eating activity, especially around parturition. This indicates ruminal buffering insufficiency and a greater risk for rumen acidification during this period. In addition, reduced eating time in early-lactation cows was accompanied by reduced drinking time. We suggest that monitoring of chewing activity can be useful to assess rumen disorder risks of the cows during the transition period and rumination-halters may also be used as a tool to identify cows which are about to calve.Dairy cows need sufficient physically effective fibre (peNDF) in their diet to induce chewing with the latter stimulating salivation and maintaining rumen health. Thus, monitoring of chewing activity can be a non-invasive tool to assess fibre adequacy, and thus helping in the optimization of the diet. The objective of this study was to investigate and compare chewing activities of cows during transition period and in the course of lactation. Simmental dairy cows, in four different production groups such as dry period (from 8 to 6 weeks ante-calving), calving (24 h before and after calving), early-lactation (7–60 days in milk), and mid-lactation (60–120 days in milk) were used in the study. Cows were fed partial mixed rations supplemented with different amounts of concentrates. The chewing and drinking activity were recorded using rumination-halters (RumiWatch System, Itin+Hoch GmbH, Liestal, Switzerland). Feed data analysis showed that the peNDF content of the partial mixed ration (PMR) was highest during dry period, decreased around parturition, reaching the nadir in the lactation, in all cases, however, exceeding the peNDF requirements. Chewing data analysis showed that rumination time decreased (p < 0.05) in the time around parturition (from 460 min/d during dry period to 363 min/d 24 h before calving) and increased again in early-lactation (505 min/d), reaching a maximum in mid-lactation (515 min/d). Eating time was lowest for cows during early-lactation (342 min/d) and the highest for those in mid-lactation (462 min/d). Moreover, early-lactation cows spent less time (p < 0.05) drinking (8 min/d) compared to other groups (e.g., 24 min/d the day before calving and 20 min/d postpartum). Monitoring of chewing activity might be a useful tool to assess rumen disorder risks and welfare of the cows during the transition period. It further shows promising results to be used as a tool to identify cows that are shortly before calving.

PSXIII-38 Hepatic reducing factors expression changes in dromedary camel during late gestation and early lactation

Abstract Tremendous stress for female livestock species occurs during transition from gestation to lactation. The liver adaptive mechanisms have evolved to protect the animal’s overall health. However, there are many unknown mediators of this process, especially in dromedary camels. This study investigated the fluctuation of gene expression for the synthesis of hepatic reducing factors in ten multiparous (2.38 ± 0.56; mean ± SEM parity) pregnant dromedary camels (527.94 ± 73.46 kg body weight). Camels were pastured daily and kept in individual stalls nightly with provision of partial mixed ration (PMR) and water. Hepatic biopsies were taken on days 60, 45, 30, and 15 antepartum (AP) and days 3, 15, 30, 45, and 60 postpartum (PP). The mRNA abundance of genes regulating the key enzymes glutamate-cysteine ligase catalytic (GCLC) and modifier (GCLM), glucose-6-phosphate dehydrogenase (G6PD), and phosphogluconate dehydrogenase (6PGD) were analyzed with qPCR technique. Statistical significances were determined by general linear model with repeated measures using IBM SPSS statistics software and mean differences with LSD test significance considered at P values &amp;lt; 0.05. Compared to d 60AP, mRNA abundance of most target genes peaked at d 3 or 15PP (P ≤ 0.02) and decreased gradually to the previous 6AP nadir, at d 30PP. Only 6PGD remained elevated until d 30PP (P = 0.03) then decreased d 45PP. The measured mRNA abundances of the GCLC, GCLM, and G6PD at d 30PP, and of 6PGD at d 45PP were lower than at d 3PP (P ≤ 0.05). In contrast with GCLC and GCLM, which did not change for the rest of the study, G6PD and 6PGD decreased slightly from d 30PP to d 60PP (P ≤ 0.05). The results corroborate the increased demand for reducing factors during transition and substantiate the increased expression of hepatic regulating factors, such as Nrf2 during this period.

Case Study: Evaluation of cooling in 3 grazing dairy farms in Georgia, USA

Our objective was to evaluate cooling systems in grazing dairy farms in Georgia during summer. This study was conducted during summer 2016 in 3 dairy farms. Farms were managed similarly and used rotary parlors with open holding pens with misters. When grazing during the day, cows were cooled by misters attached to pivots without access to shade. Cows were milked at 0400 and 1500 h and fed a partial mixed ration. In farm A, cows were fed for 3.5 h after each milking in an open feeding pad with concrete bunks equipped with misters, which operated only during afternoon feeding. In farm B, cows were fed 2 h before and 2 h after each milking in an open ridge barn with concrete feed bunks equipped with overhead sprinklers, which only operated before afternoon milking. In farm C, cows were fed for 3.5 h after milking in an open ridge barn with concrete bunks fitted with fans and soakers over the feedbunks. Ten cows per farm were randomly selected to have their vaginal temperature (VT) measured for 3 d. Cow’s genotype (Holstein or Holstein × Jersey) was determined by phenotype. Environmental data were obtained from local weather stations. Average air temperature and relative humidity over the 3-d period were 29°C and 70%. A farm by hour interaction ( P < 0.01) was observed for VT. From morning milking to departure from feeding areas, VT of all cows gradually decreased, but VT of cows in farm C decreased the most rapidly. After leaving the feeding areas, cows in farms B and C experienced a small increase in VT, but cows in farm A maintained VT. Cows in farm A maintained lower VT than cows in farms B and C while in feeding areas after afternoon milking. The VT of all cows increased after leaving feeding pens, but the highest VT was observed in cows in farm B. Regardless of farms, Holstein cows had lower VT than Holstein × Jersey cows during afternoon milking but higher VT after leaving the feeding areas. In summary, holding pen misting was effective for reducing body temperatures, and pivot cooling maintained VT. Holstein and crossbred cows responded differently to cooling and solar radiation.

A whole-farm investment analysis of a partial mixed ration feeding system for dairy cows

Aim A dairy farm in south-west Victoria was analysed to discern the impact on profit and risk of changing from a feeding system in the base case where grain was fed in the dairy and forage in the paddock, to a partial mixed ration (PMR) or a formulated grain mix (FGM) feeding system. Context A PMR feeding system involves feeding a well formulated mixed ration to a grazing dairy herd and typically requires the use of specialised machinery to mix and feed out the forage and grain components of the ration together onto a feed pad. In a FGM feeding system, the same formulated ration fed in the PMR system is used, but the grain component of the ration is fed using the existing feeding system in the dairy with the hay component fed in the paddock. Method The analysis used data from experiments recently performed to establish milk responses to mixed ration feeding under Australian conditions. The case study farm comprised 244 ha and a herd of 420 self-replacing Holstein-Friesian cows that calved from May to July. The herd feeding system was based on grazed pasture, grain fed in the dairy at milking and hay fed in the paddock. Supplementary feed comprised ~50% of metabolisable energy in the diet of the milking cows. The pre-existing feeding system was altered to incorporate either a PMR system or a FGM system. An increased herd size of an extra 100 cows, plus the PMR or FGM systems, was also tested. Key results All systems analysed were more profitable than the base case. Increasing the herd by 100 cows was the most profitable option for both the PMR and FGM systems, but intensifying the system by increasing cow numbers also had the most variability in profit. Conclusions and implications The FGM system was the most profitable system because milk production could be increased without the costs of extra labour, depreciation and repairs and maintenance associated with using a mixer wagon to feed the ration. The FGM system presents an option for farmers to expand or intensify their systems without needing to construct a feed pad or invest in extra machinery and equipment.

Effects of concentrate location on the behavior and production of dairy cows milked in a free-traffic automated milking system

The objective of this study was to determine whether the amount of concentrate allowance in an automated milking system (AMS) affects partial mixed ration (PMR) sorting behavior, milking activity, and production of lactating dairy cows fed isocaloric diets. Fifteen primiparous Holstein cows were used in a crossover design with 28-d periods, 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 higher-concentrate PMR (H-PMR) with a pelleted concentrate allowance of 3.0 kg/d on a dry matter (DM) basis in the AMS, or a lower-concentrate PMR (L-PMR) with a pelleted concentrate allowance of 6.0 kg/d in the AMS. As designed, cows on the L-PMR had greater AMS concentrate intake (6.3 vs. 3.1 kg/d of DM) compared with the H-PMR. The standard deviation for mean concentrate intake among days increased from 0.38 to 1.0 kg/d with greater targeted AMS concentrate intake. When fed the L-PMR diet, PMR intake was reduced compared with when cows were fed the H-PMR diet (17.1 vs. 19.1 kg/d of DM). The reduction in PMR intake was compensated for by greater AMS concentrate intake; thus, cows on the L-PMR had greater total dry matter intake (DMI; 23.6 vs. 22.3 kg/d). Cows sorted against long (>19 mm) and fine (<4 mm) PMR particle fractions, and in favor of medium (8 to 19 mm) and short (4 to 8 mm) PMR fractions when on the H-PMR treatment, but only sorted against the medium and in favor of the short PMR fractions on the L-PMR treatment. PMR eating rate and total time spent eating PMR did not differ significantly between the 2 treatments; however, meal size tended to be larger when cows were fed the H-PMR compared with the L-PMR (2.2 vs. 2.1 kg DM/meal). Cows tended to spend 30.8 min/d more time lying down when fed the L-PMR. On the L-PMR treatment, cows tended to have more voluntary AMS visits (5.9 vs. 4.6 visits/d), were fetched less (0.1 vs. 0.5 times daily), and had a greater milking frequency (3.5 vs. 3.0 milkings/d) compared with when they were on the H-PMR treatment. However, milk yield was not affected by treatment. These data suggest that allocating a greater proportion of total dietary concentrate to the AMS, in a free-traffic setup, may improve milking activity and decrease the need for fetching, as well as promoting greater amounts of and maintaining consistency in total dry matter consumption.

Effect of alternating total mixed ration and pasture feeding on the fatty acid content and health indices of Jersey and Fleckvieh x Jersey milk

Certain fatty acids (FAs), such as omega-3 and conjugated linoleic acid (CLA) are considered essential FAs with beneficial health effects for humans. Milk is considered a relatively inexpensive and readily available source of these FAs and is part of a recommended healthy daily diet. The aim of the study was to determine the effect of diet changes on the FA composition of Jersey (J) and Fleckvieh x Jersey (FxJ) milk. Cows were alternately put on kikuyu-ryegrass pasture, followed by a feedlot system, then returned to kikuyu-ryegrass pasture for four weeks each. The same concentrate mixture was fed to cows regardless of feeding system. The feedlot system consisted of a partial total mixed ration (pTMR). Milk samples were collected two and four weeks after diet changes and stored at −20 °C until laboratory analysis by gas chromatography. The FA concentration of milk was not affected by breed, although it was affected significantly by diet changes. Most notably, the total omega-3 and -6 FAs decreased when cows were fed pTMR while increasing when the diet was changed back to pasture feeding. The CLA content of milk was similarly affected. That is, concentrations decreased significantly when the cows were on the pTMR diet and increased when cows were put back on the pasture-based diet. The results suggested that the health benefits of milk fat are affected negatively when cows are fed pTMR compared with being fed in a pasture-based system. The health benefits of milk are reduced owing to decreased levels of the CLA content of milk fat. Therefore, feeding additional hay in a pasture-based production system should be reconsidered when aiming to produce milk that provides health beneficial qualities. Keywords: breed, diet, n-3 fatty acid, n-6 fatty acid, pasture, Fleckvieh

Effect of late prepartum fibre-based diets on the live weight changes and reproduction of Holstein cows in the subsequent lactation period

The objective of this study was to evaluate two late prepartum fibre-based diets that differed in non-structural carbohydrate (NFC) and protein levels on live weight (LW) changes and fertility traits of Holstein cows until 120 days postpartum. At 30 days before calving, 120 pregnant Holsteins (heifers, n = 54 and dry cows, n = 66) from the Elsenburg herd were assigned to two nutritional treatments according to parity, expected calving date, LW, and milk production during the previous lactation. Prepartum heifers and cows were fed independently a similar type and level of a prepartum concentrate, associated with an ad libitum intake of either unchopped oat hay for the control group or a partial total mixed ration (pTMR: oat hay (48%), lucerne hay (43%) and soybean oil cake meal (9%)) for the treatment group. After parturition, cows in both the control and treatment groups were maintained on ad libitum cultivated irrigated kikuyu-ryegrass pastures, supplemented each with a post-partum concentrate of 7 kg/day from calving until 120 days in milk (DIM). As expected, young and still growing primiparous cows were significantly lighter in pre- and post-partum LW traits compared with mature multiparous cows (parity &gt; 3). Prepartum LW of cows was similar between the control and the treatment in both parity groups. Post-partum LW of the primiparous cows differed significantly between the control and the treatment, which were 488 ± 9 and 507 ± 13 kg, respectively. However, no difference was observed in terms of post-partum LW of multiparous cows of the control and the treatment groups, which were 579 ± 10 and 579 ± 8 kg, respectively. Primiparous cows that received the prepartum oat hay-based diet showed significant decrease in post-partum LW loss changes, LWnadir, LW loss at nadir and rate of LW loss from calving to LWnadir in comparison with their counterparts on the prepartum pTMR-based diet, but these LW traits were similar in multiparous cows. Prepartum diets did not have an effect on post-partum fertility parameters of the multiparous cows, whereas primiparous cows that received the control diet recorded a significantly longer interval from calving to first service (CFS) in the subsequent lactation in comparison with their counterparts fed the treatment diet i.e. 117 ± 9 and 86 ± 8 days, respectively. Proportions of cows that were pregnant at 120 DIM were similar in the subsequent lactation between groups that received the prepartum oat hay- and pTMR-based diets in both parity groups. Further research is required to investigate different prepartum feeding periods and nutritional approaches involving various levels and sources of energy and protein nutrients to encourage post-partum metabolic and hormonal responses that benefit the fertility of dairy cows in the subsequent lactation.Keywords: Dairy, dry period, non-structural carbohydrate, protein, postpartum, pregnancy

Effect of Milking Frequency on Body Condition Score, Somatic Cell Count, and Reproductive Performance of Dairy Cows Milked by An Automatic Milking System

The objective of this study was to determine the effect of milking frequency using an Automatic Milking System (AMS) on body condition scores (BCS), somatic cell count (SCC), and reproductive performance of Holstein cows. The study was conducted in Hiroshima University Farm. Eight multiparous cows and four primiparous cows were divided into two treatments of groups (2 and 4 times milking frequency). Cows were fed by Partial Mixed Ration (PMR) ad libitum and concentrate diet (5-8 kg) at every milking. The PMR consisted of Italian ryegrass silage 35% dry matter (DM), oat hay (8% DM), alfalfa hay (8% DM), pellet bit pulp (8% DM), formula feed (39% DM), minerals and vitamin. The PMR nutrients contents were 13.6% crude protein (CP) and 70% total digestible nutrient (TDN), while concentrate contained 20.6% CP and 82.4% TDN. On days 20, 35, and 50 postpartum, BCS was observed, and milk samples were collected for SCC analysis. Reproductive performance data collected were S/C, calving interval, and postpartum mating. The MIXED model for repeated measures (SAS 2004) was used for testing the difference in BCS and SCC. Significance was declared at P < 0.05, and tendency at P < 0.10. The research showed that no difference on BCS and SCC between 2 and 4 times milking by AMS, but the probability of occurrence of high SCC (> 100,000) was lower for four times milking cows than 2 times milking cows (6% vs 59%). The effect of milking frequency did not show any difference on S/C, calving interval, and postpartum mating. Increasing milking frequency may positively affect on SCC without any effects on BCS and reproductive performance in this experiment.

Effect of the amount of concentrate offered in an automated milking system on dry matter intake, milk yield, milk composition, ruminal digestion, and behavior of primiparous Holstein cows fed isocaloric diets

The objective of this study was to determine if the quantity of concentrate provided in an automated milking system (AMS) affects dry matter intake (DMI), attendance to the AMS, milk and milk component yield, feeding behavior, cow activity, and ruminal fermentation of lactating dairy cows fed isocaloric diets. Eight ruminally cannulated primiparous Holstein cows were used in a replicated 4 × 4 Latin square design with 28-d periods. Cows were housed in a freestall facility with a guided-traffic (feed-first) flow barn design. Treatments included 0.5, 2.0, 3.5, or 5.0 kg/d of dry matter of pellet in the AMS with an equivalent reduction of the same pellet in the partial mixed ration (PMR). Days 21 to 24 of each treatment period were used for DMI, milking performance (visits, yield, and composition), behavior, and ruminal pH determination, and d 25 to 28 were used for ruminal short-chain fatty acid and ammonia concentrations as well as total-tract digestibility. As imposed, consumption of AMS pellet linearly increased, equating to 0.50, 2.00, 3.49, and 4.93 kg of dry matter/d for the 0.5, 2.0, 3.5, and 5.0 kg/d treatments, respectively. Correspondingly, the standard deviation in AMS pellet intake among days linearly increased from 0.06 to 0.85 kg of dry matter/d as the quantity of concentrate in the AMS increased from 0.5 to 5.0 kg. The PMR DMI decreased linearly with increasing AMS concentrate allocation, but total DMI (PMR + AMS) was not affected (25.3 kg/d). As the AMS concentrate allocation increased, the selection against particles retained on an 18-mm sieve linearly increased and selection against particles retained on the pan decreased. Milking frequency (3.22 milkings/d), milk yield (37.5 kg/d), milk fat yield (1.43 kg/d), and milk protein yield (1.22 kg/d) were not affected; however, milk urea nitrogen concentration decreased linearly with increasing AMS concentrate. Ruminal pH averaged 6.18 and was not affected by AMS concentrate. Total ruminal short-chain fatty acid concentration was greatest when 3.5 kg of concentrate was allocated in the AMS and ruminal ammonia decreased linearly with increasing AMS concentrate. Time spent lying, the number of lying bouts, and average bout duration were not affected by treatment. These data indicate that increasing the quantity of concentrate in the AMS increases daily variability in AMS concentrate intake while decreasing PMR intake without affecting voluntary visits to the AMS and milk or milk component yield. As such, under isocaloric dietary settings, increasing the supply of pellet in the AMS is not likely to affect voluntary visits to the AMS, milk and milk component yields, or ruminal fermentation.

Effects of an individual cow concentrate strategy on production and behavior

The aim of this study was to investigate the effects of a concentrate strategy based on the individual cow partial mixed ration (PMR) intake compared with a flat rate. Half of the cows were fed the individual concentrate strategy, whereas the other half were fed the control strategy. The individually fed cows were offered a concentrate proportion equal to 30% of the ad libitum intake of the PMR in the automatic milking system, and the control cows were offered 3 kg of concentrate/d in the automatic milking system. The cows (83 Holstein and 64 Jersey), kept in 2 separate groups, were blocked between the treatments according to expected calving date, breed, and parity and were randomly divided between treatments. Lactation was divided into 3 periods (early, mid, and late lactation), and the MIXED and GLIMMIX procedures in SAS (SAS Institute Inc., Cary, NC) were used to analyze the production and behavioral responses. The response trajectories during lactation were analyzed with a MIXED procedure fitted by Wilmink parameters. The individually fed cows had a higher concentrate intake and a lower PMR intake than control cows. Moreover, the total dry matter intake and energy-corrected milk yield did not differ between concentrate strategies. The actual average concentrate intake reached 19% of the PMR intake during mid lactation and not 30% of the PMR intake, as intended with the strategy. This was due to leftovers and lower allocation than intended. The cow behavior did not differ between concentrate strategies. However, variation in PMR intake and eating rate between cows fed individually was lower during mid lactation and lower for lying bouts during early lactation compared with control cows. This may indicate that an individual cow concentrate strategy results in a more stable PMR intake and time budget, which potentially could improve welfare, but this needs further investigation. The overall conclusion is that the cows were robust to adjustments in the concentrate allowance.

Production, milk fatty acid profile, and nutrient utilization in grazing dairy cows supplemented with ground flaxseed

Flaxseed has been extensively used as a supplement for dairy cows because of its high concentrations of energy and the n-3 fatty acid (FA) cis-9,cis-12,cis-15 18:3. However, limited information is available regarding the effect of ground flaxseed on dry matter intake (DMI), ruminal fermentation, and nutrient utilization in grazing dairy cows. Twenty multiparous Jersey cows averaging (mean ± standard deviation) 111 ± 49 d in milk in the beginning of the study were used in a randomized complete block design to investigate the effects of supplementing herbage (i.e., grazed forage) with ground corn-soybean meal mix (control diet = CTRL) or ground flaxseed (flaxseed diet = FLX) on animal production, milk FA, ruminal metabolism, and nutrient digestibility. The study was conducted from June to September 2013, with data and sample collection taking place on wk 4, 8, 12, and 16. Cows were fed a diet formulated to yield a 60:40 forage-to-concentrate ratio consisting of (dry matter basis): 40% cool-season perennial herbage, 50% partial total mixed ration, and 10% of ground corn-soybean meal mix or 10% ground flaxseed. However, estimated herbage DMI averaged 5.59 kg/d or 34% of the total DMI. Significant treatment by week interactions were observed for milk and blood urea N, and several milk FA (e.g., trans-10 18:1). No significant differences between treatments were observed for herbage and total DMI, milk yield, feed efficiency, concentrations and yields of milk components, and urinary excretion of purine derivatives. Total-tract digestibility of organic matter decreased, whereas that of neutral detergent fiber increased with feeding FLX versus CTRL. No treatment effects were observed for ruminal concentrations of total volatile FA and NH3-N, and ruminal proportions of acetate and propionate. Ruminal butyrate tended to decrease, and the acetate-to-propionate ratio decreased in the FLX diet. Most saturated and unsaturated FA in milk fat were changed. Specifically, milk proportion of cis-9,cis-12,cis-15 18:3, Σn-3 FA, and Σ18C FA increased, whereas that of cis-9,cis-12 18:2, Σn-6 FA, Σ odd-chain FA, Σ<16C FA, and Σ16C FA decreased with feeding FLX versus the CTRL diet. In conclusion, feeding FLX did not change yields of milk and milk components, but increased milk n-3 FA. Therefore, costs and industry adoption of premiums for n-3-enriched milk will determine the adoption of ground flaxseed in pasture-based dairy farms.

Effect of diets containing sulfate or chloride-based anionic salts, fed to grazing prepartum dairy cows, on concentrations of Ca in plasma, disease incidence and milk yield

AIMS: To compare the effect of two partial mixed ration diets containing either sulfate or chloride-based anionic salts, fed to grazing prepartum dairy cows, on concentrations of Ca, Mg, P and beta-hydroxybutyrate (BHB) in plasma, disease incidence and milk yield during the early postpartum period.METHODS: The study was conducted on a seasonal-calving grazing dairy farm located in Benton (MO, USA). In August 2016, two groups of 200 cows were randomly assigned at 30 days before expected parturition to receive either a sulfate or chloride-based anionic diet, to achieve a dietary cation–anion difference (DCAD) of −25 mEq/kg DM. Cows were fed partial mixed rations to provide 50% of their DM intake, with 50% provided by grazing fescue pasture. Urine samples were collected from 20 cows from each group once a week for 5 weeks until calving for pH assessment. At parturition, 42 cows per group were selected at random and blood samples collected on Days 1, 2, 3 and 7 postpartum. The study continued until 100 cows per group calved. Health events and cumulative milk yield until 30 days postpartum were recorded. Concentrations of Ca, P, and Mg in plasma at Days 1, 2, 3, and 7, and BHB in plasma at Day 7 postpartum were assessed.RESULTS: Mean urine pH was lower in cows in the chloride than sulfate group (p≤0.06) on four of five sampling occasions. Mean concentrations of Ca in plasma on Day 1 were 2.00 (95% CI=1.94–2.05) and 1.91 (95% CI=1.88–1.97) mmol/L for the chloride and sulfate groups, respectively (p=0.15), and on Day 3 were 2.03 (95% CI=1.97–2.08) and 1.90 (95% CI=1.84–1.96) mmol/L, respectively (p=0.038). Concentrations of Mg, P and BHB in plasma and incidence of diseases postpartum were similar in both groups (p>0.05). There were no cases of clinical hypocalcaemia in either group.CONCLUSIONS AND CLINICAL RELEVANCE: Prepartum cows fed a partial mixed ration with a negative DCAD containing chloride-based anionic salts and free access to a fescue pasture had lower prepartum urine pH, and higher concentrations of total Ca in plasma during the first week postpartum, than cows receiving a partial mixed ration containing sulfate-based anionic salts.

Effects of berry seed residues on ruminal fermentation, methane concentration, milk production, and fatty acid proportions in the rumen and milk of dairy cows

Strawberry (SB), black currant (BC), and raspberry seed (RB) residues were used in 3 experiments to study their effects on ruminal fermentation, methane concentration, and fatty acid (FA) proportions in the ruminal fluid and milk of dairy cows. Initially, a batch fermentation in vitro study (experiment 1) was performed to investigate the effects of the 3 berry residues on basic ruminal fermentation parameters. Total volatile fatty acid concentrations, including acetate, propionate, and butyrate, increased in the BC group compared with other treatments. Based on the preliminary in vitro results, 2 consecutive in vivo experiments were conducted using 4 Polish Holstein-Friesian cows fitted with rumen cannulas (experiment 2) and 30 lactating Polish Holstein-Friesian dairy cows (experiment 3) in a replicated 2 × 2 crossover design. Cows in both experiments received a partial mixed ration (PMR) in 2 variants: (1) a control diet of PMR + 2 kg of concentrate (control); (2) PMR + 2 kg of BC seed residues (BC). The BC diet did not mitigate ruminal methane production. Ruminal fermentation (experiment 2) was not affected by the BC diet; however, the concentrations of C18:1 trans-11 and C18:2 cis-9,trans-11 increased significantly by 91 and 131%, respectively. Likewise, concentrations of total trans C18:1 and total monounsaturated FA in ruminal fluid were increased significantly by BC seed residues. In experiment 3, BC significantly increased milk fat C18:1 trans-11, C18:2 cis-9,trans-11, n-3, n-6, and polyunsaturated FA concentrations without affecting milk production performance. In conclusion, the amount (2 kg/d) of BC used in this study did not adversely affect ruminal fermentation or milk production and composition. However, using BC increased proportions of unsaturated FA and conjugated linoleic acid in milk. Although dietary BC did not exert a strong methane inhibition effect, it could represent an inexpensive alternative concentrate to improve beneficial FA in milk without negative effects on rumen fermentation and production parameters in dairy cows. Incorporation of berry seed residues in diets would be profitable economically and nutritionally for dairy cattle production.

PSX-2 In vitro evaluation of the inclusion of a fibrous concentrate to partial Total Mixed Ration for lambs.

PSX-2 In vitro evaluation of the inclusion of a fibrous concentrate to partial Total Mixed Ration for lambs.

Changes of ruminal pH, rumination activity and feeding behaviour during early lactation as affected by different energy and fibre concentrations of roughage in pluriparous dairy cows

ABSTRACTThe aim of this study was to assess differences of ruminal pH and rumination activity between the prepartal and postpartal period of cows and to investigate changes of feeding behaviour and ruminal fermentation depending on postpartal rations with slight differences in roughage energy and fibre concentration. Therefore, 11 rumen-cannulated German Holstein cows were used from 3 weeks antepartum until 16 weeks postpartum. During the dry period, all cows received the same diet. After calving cows were assigned to two groups receiving partial mixed rations with different energy concentrations (6.1 MJ NEL/kg DM [moderate], with 18% straw on dry matter [DM] basis, group MR) or 6.5 MJ NEL/kg DM [high], with 6% straw on DM basis, group HR). In both groups, concentrates were supplied on average at 45% of total DM intake. Circadian measurements of ruminal pH, ruminal temperature and rumination activity were conducted weekly during the transition period and bi-weekly after week 4 postpartum. Throughout the postpartal period, feed intake behaviour was measured, and twice during the experiment, rumen fluid composition and net-acid-base excretion in urine were determined. Mean ruminal pH, feeding behaviour, rumination activity and rumen fluid composition did not differ between the groups, whereas group HR exhibited higher diurnal variations of pH and had a lower rumen temperature than group MR postpartum. However, these differences also occurred during the prepartal period when groups received equal rations. It was observed that ruminal pH values and the risk for subacute ruminal acidosis (SARA) were increased during postpartal period, whereby the circadian pH values showed high cow-individual variations. Overall, differences of energy and fibre concentrations in roughage did not affect the observed variables, whereby it should be noted that the number of cows was quite low in this study. Our results suggest that the ruminal pH characteristics are rather cow individual, indicating that cows presumably differ in their susceptibility to develop SARA.

Particle size distribution of forages and mixed rations, and their relationship with ration variability and performance of UK dairy herds

The particle size of the ration has been proposed as a key factor, along with its fibre and non-forage carbohydrate concentration, to ensure healthy rumen function and optimal performance of dairy cows. The current particle size distribution recommendations for forages and rations are primarily based on lucerne-haylage and maize silage (MS) and may not be suitable for the wetter grass silage (GS) based rations typically fed in Northern Europe. In order to characterize the particle size distribution of forages and rations in the UK, fifty commercial dairy herds feeding a range of GS and MS based rations were sampled during the winter of 2015/2016. The particle size distribution of the fresh forages and mixed rations (MR; total and partial mixed rations) were analysed using a modified Penn State Particle Separator with six screens of hole size 60, 44, 26.9, 19, 8, and 4 mm. The fresh MR was collected at 5-equally-spaced locations along the length of the feed-face for each herd within 5-min of feeding to determine the consistency of ration mixing, and again from the same locations 4 h post-feeding. Grass silage was fed on 50 herds, with 80.3% of the dry matter (DM) being retained above the 19 mm sieve, which is considerably higher than the North-American recommendations for lucerne-haylage. The particle size distribution of MS followed the general recommendations for North American forages, however, the 8–19 mm fraction was higher and the <4 mm lower. The >60 mm fraction of the MR had the lowest (0.1% DM) DM retention, and the 8–19 mm fraction the highest (34.9% DM). The MR had a higher proportion of particles retained on the 26.9 mm sieve when GS was the sole forage. Fifty eight % of herds were considered to have either moderately or poorly mixed rations, whilst 66% had evidence of diet selection (either preferential consumption or selective refusals). Particle size of the MR accounted for 33% of the variance in the milk fat content and 12% of milk yield. In conclusion, the particle size distribution of the GS and MR fed on UK dairy herds is different from the current recommendations, suggesting that the particle size of UK dairy rations is too long or new guidelines using additional sieves with larger pore sizes are required. There is also a high proportion of herds with poor mixing and/or evidence of diet selection.

The effect of the forage-to-concentrate ratio of the partial mixed ration and the quantity of concentrate in an automatic milking system for lactating Holstein cows

This study was conducted to evaluate the effects of the forage-to-concentrate ratio of the partial mixed ration (PMR) and the quantity of concentrate offered in an automated milking system (AMS), in a feed-first guided-flow barn, on the behavior and performance of dairy cows. Eight ruminally cannulated multiparous Holstein cows were used in a replicated 4 × 4 Latin square balanced for carry-over effects. Treatments were arranged in a 2 × 2 factorial consisting of a PMR that contained (dry matter basis) either a low (54:46; L-FOR) or a high (64:36; H-FOR) forage-to-concentrate ratio and AMS concentrate provision to achieve low (2 kg/d; L-AMS) or high (6 kg/d; H-AMS) intake. Each period consisted of 28 d with 6 d for dietary transition, 13 d for adaptation, and 9 d of collection. The first 4 d of data and sample collection were used to evaluate behavioral data (milking frequency, feeding behavior, and standing and lying behavior) and ruminal pH. Subsequently, a sampling device removal day was provided, and the last 4 d were used to evaluate ruminal fermentation and apparent total-tract digestibility. All 9 d were used for milk yield measurement, and the 8 d were used for dry matter intake measurement. Cows fed the H-AMS consumed 3.5 kg/d less PMR while consuming 4.2 kg/d more AMS concentrate, but total dry matter intake (PMR+AMS) was not affected by treatments averaging 27.3 kg/d. Although cows fed H-AMS had greater concentrate intake, they also had greater variability for AMS concentrate intake among days (0.85 vs. 0.25 kg/d, respectively). The number of PMR meals and PMR eating behavior were not affected by the PMR or AMS treatments. Feeding H-AMS did not affect milking frequency averaging 3.63 milkings/d, but tended to increase milk yield by 1.25 kg/d relative to L-AMS. Likewise, cows fed the L-FOR tended to have greater milk yield relative to H-FOR (39.3 vs 37.9 kg/d, respectively), but had greater holding area time. Minimum ruminal pH tended to be lower for cows fed L-FOR compared with cows fed H-FOR but was not affected by the AMS concentrate treatment. When fed the L-FOR, feeding the H-AMS increased total short-chain fatty acid concentration in the rumen relative to cows fed L-AMS, whereas the response for H-FOR was not affected by the AMS concentrate. These data suggest that feeding H-AMS may improve milk yield, but also increases the day-to-day variability in AMS concentrate consumption. Feeding a L-FOR PMR may increase milk yield without affecting variability in AMS concentrate consumption; however, it may reduce ruminal pH and increase the time spent in the holding area compared with cows fed a H-FOR PMR.

Analysis of lactating cows in commercial Austrian dairy farms: diet composition, and influence of genotype, parity and stage of lactation on nutrient intake, body weight and body condition score

This study characterises diets used on-farm and examines nutrient and feed intake (DMI) together with other animal specific traits (body weight, milk yield, body condition score). Data came from the project ‘Efficient Cow’ to develop efficiency traits for Austrian cattle breeding (161 farms, 6105 cows, one-year data collection). Most diets were grass silage- or maize silage-based. Nearly half (42.8%) of the records were diets with separately fed concentrate or were partial mixed rations (PMR, 42.9%), and 12.0% were total mixed rations (TMR). Feedstuffs from permanent grassland ranged between 62% (TMR) and 84% (pure forage diets) of forage. Partial mixed rations and TMR showed the highest average proportion of maize silage (30%). The little importance of pure forage diets and pasture reflected the above-average production level of the farms. Most production traits increased from Fleckvieh (FV) over FV groups with increasing Red Holstein (RH) genes to Holstein Friesian (HF). The FV group with highest RH proportion and HF had the highest energy corrected milk yield (ECM) and DMI (29.3 vs. 29.2 kg ECM/d; 20.8 vs. 20.9 kg DMI/d). Brown Swiss (BS) and FV had lower levels (26.5 vs. 26.7 kg ECM/d; 19.8 vs. 19.7 kg DMI/d). Body condition declined in relation to proportion of RH genes from FV to HF (FV 3.42 Pt., BS 2.88 Pt., HF 2.61 Pt.). The study allowed a broad view on the continuous spectrum between dual-purpose and dairy breeds due to the different characteristics of metabolism and on the common diets on Austrian dairy farms.

Short-term responses in production and behavior during periods of change in concentrate allowance for dairy cows

The aim of this study was to investigate the short-term responses of dairy cows during periods of change in the concentrate allowance in an automatic milking system. The experiment had a design with a 2 × 2 factorial arrangement including 2 types of concentrates and 2 amounts of concentrates (type O: mix of pelleted concentrate and steamrolled, acidified barley; type S: pelleted) in amounts of 3 and 6 kg/d. The experiment length was 11 wk. The concentrate type changed between wk 6 and 7 and included both increase and decrease in concentrate allowance for each concentrate type. The concentrate allowance was changed by 0.5 kg/d over 6 d. The 96 cows (48 Danish Jersey, 48 Danish Holstein) included in the experiment were blocked according to breed, parity, and days in milk, and randomly divided into 8 groups of treatment order. The cows visited the automatic milking unit more often when concentrate type O was offered, but not when an increased concentrate allowance was provided. The changes in concentrate intake and partial mixed ration (PMR) eating time showed a symmetrical pattern between the periods of increasing allowance and decreasing allowance. However, PMR intake and milk yield varied in the magnitude of the responses, indicating that these responses may not be driven by the same underlying mechanisms during increase and decrease in concentrate allowance. The daily lying time increased and the PMR eating rate decreased during periods of both increase and decrease in concentrate allowance. We found no significant change in milk yield during increase in concentrate allowance, despite a higher milk yield during periods with constant concentrate allowance at the high concentrate amount; however, the milk yield decreased during periods of decrease in concentrate allowance. Visit frequency, lying time, and steps changed during periods of changes in concentrate allowance without showing any differences at the constant concentrate allowance. In conclusion, these results indicate that it may be difficult to adjust the individual concentrate allowance based on the short-term responses of the cow.

Does the location of concentrate provision affect voluntary visits, and milk and milk component yield for cows in an automated milking system?

Eight Holstein cows were used in a cross-over design to test whether concentrate allocation in an automated milking system (AMS) affects dry matter intake (DMI) and milk production. Cows were fed a high-energy partial mixed ration (HE-PMR) with 0.5 kg of AMS concentrate or a low-energy PMR (LE-PMR) with 5.0 kg of AMS concentrate. The AMS concentrate intake was greater and PMR intake was reduced for LE-PMR than HE-PMR. Milk, fat, and protein yields were not affected by treatment. In a guided-traffic flow barn, providing a PMR with greater energy density increases DMI, but has no effect on milk and milk component yield.