Potential of a rumen bolus containing 1,25-dihydroxyvitamin D3 glycosides for the prevention of hypocalcaemia in primiparous and multiparous dairy cows

Periparturient hypocalcaemia is a widespread metabolic disorder in dairy cows. Clinical and subclinical cases occur primarily in multiparous (Multi) cows, but subclinical cases have also been reported in primiparous (Primi) cows. A preventive strategy was investigated by administering the physiologically active vitamin D3 metabolite, 1,25-dihydroxyvitamin D3 (1,25-dihydroxycholecalciferol, 1,25(OH)2D3) as a rumen bolus. The bolus contained tablets of 1,25(OH)2D3 glycoside extract from Solanum glaucophyllum (SGE), releasing SGE over several days. The aim was to study the effect of a bolus containing 0 (C) or 500 µg (SGE) of 1,25(OH)2D3 on 1,25(OH)2D3 and mineral status in periparturient cows up to three weeks into lactation and on colostrum, milk and calves' blood mineral contents. The bolus was administered three to four days prior to expected calving to Primi and Multi cows fed a herbage-based diet (dietary cation-anion difference of +522 mEq/kg DM). One C or SGE bolus was applied to 12 Primi and 12 Multi cows. Blood was regularly sampled (and selected a posteriori for antepartum samples) in regard to the actual calving day (d0), immediately prior to bolus application and at day -2, 0.5, 1, 1.5, 2, 4, 8, 11, 15, 18 and 22. Additional samples included urine (at bolus application, d0.5 and d2), colostrum, milk samples (weekly) and calves' blood (d2). Blood serum 1,25(OH)2D3 increased between d0.5 and d2 in Primi-SGE, but remained unchanged in Primi-C, as did parathyroid hormone (PTH) and Ca in all Primi. Urinary Ca of Primi-SGE was increased on d2, indicating regulation of Ca excess. Three Multi-C cows with confirmed clinical hypocalcaemia needed treatment and thus were excluded from the dataset and replaced. Blood serum 1,25(OH)2D3 and PTH increased while Ca dropped by 40% between d0.5 and d2 in Multi-C, whereas 1,25(OH)2D3, Ca and PTH remained unchanged in Multi-SGE. Blood serum carboxyterminal telopeptide of type I collagen was higher in Primi than in Multi and increased with time, except in Primi-C. Mineral contents in colostrum, milk and blood serum of calves were not influenced to a relevant degree. In conclusion, Primi-C did not, in contrast to Multi-C, develop subclinical hypocalcaemia (<2.0 mmol Ca/l). Prevention of hypocalcaemia with one SGE bolus applied three to four days prior to expected calving was successful in maintaining blood Ca within normal range in Multi over the critical first two days and up to the first three weeks of lactation, without any observed detrimental effects on cows or calves

Pharmacokinetics of 1,25-dihydroxyvitamin D3 glycosides from Solanum glaucophyllum extract given in a rumen bolus on blood mineral profiles in dry pregnant dairy cows.

Providing tablets of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), the biologically active metabolite of vitamin D3, in a rumen bolus may be used as prevention for periparturient hypocalcemia in dairy cows. This study investigated the pharmacokinetics of 1,25(OH)2D3 glycosides extracted from Solanum glaucophyllum (SGE) on blood serum 1,25(OH)2D3, Ca, P and Mg response in dry pregnant dairy cows. Boluses contained tablets of SGE which differed in their release properties (rapid release, slow release and combination) and galenics (200 μg uncoated, 300 μg and 500 μg uncoated or coated, 2 × 500 μg uncoated). Nineteen blood samples were collected from 29 cows between 96 h before and 336 h after bolus administration. Blood serum 1,25(OH)2D3, Ca and P increased between 12 h and 120 h, 12 h and 264 h and 24 h and 264 h, respectively. Highest values were reached at 30 h, 72 h and 120 h for 1,25(OH)2D3, Ca and P, respectively. Baseline values were then reached at 216 h for 1,25(OH)2D3 and 336 h for Ca and P. Concentration of Mg decreased between 24 h and 216 h, before reaching values comparable to baseline at 264 h. Highest Ca values were obtained with the combined rapid and slow release properties (500 μg) and there was no effect from coating on pharmacokinetics. In conclusion, the antepartum oral SGE bolus administration may be suitable for the prevention of periparturient hypocalcemia

Increasing the proportion of hazel leaves in the diet of dairy cows reduced methane yield and excretion of nitrogen in volatile form, but not milk yield

Various feeds for ruminants have been identified that help to mitigate the greenhouse gas methane. However, even when there has been success in suppressing absolute methane emissions, intake, digestibility, and performance often decline in parallel. Ideal dietary levels of effective feeds would reduce methane production without affecting performance-related variables. Such favorable associative effects have been demonstrated in vitro by combining a high-quality forage with plants rich in phenols. In the present study, the tannin-rich leaves of hazel (Corylus avellana) gradually replaced (from 0 to 820 g/kg) a high-quality forage (dried alfalfa) in 20 types of experimental pellets fed to 20 mid-to-late lactating cows. Additionally, the cows were fed a mixed basal ration and some concentrate. The proportion of hazel in the 20 complete diets ranged from 0 to 400 g/kg dry matter. After 14 days of adaptation, 8 days were used for intensive sampling of feces (including markers for determining digesta retention time), urine, and milk. In addition, cows stayed for 2 days in open-circuit respiration chambers. Hazel leaves reduced the feed intake only slightly. Digestibility declined and mean digesta retention time was prolonged with increasing hazel proportion, likely due to the lower feeding value of the hazel leaves compared to the alfalfa. As aimed for, there were no significant effects on energy-corrected milk yield, body energy, and body N retention with increasing hazel intake, even though methane emission clearly declined in absolute term and per unit of digestible organic matter and tended to decrease per unit of energy corrected milk. In addition, increasing hazel proportions strongly shifted N excretion from urinary N (which declined from about 300 to 100 g/kg N intake) to fecal N. This could also be anticipated from the sharp decline in milk urea concentration (from about 35 to 10mg/dL). In conclusion, hazel leaves as a feed supplement for dairy cows showed a high palatability within 3 weeks of feeding in dairy cows and great potential to mitigate emissions of methane and nitrogen in volatile form at maintained production levels. No favorable associative dosage effects seem to exist when combining tannin-rich hazel leaves with the high-quality forage alfalfa in a different proportions to a mixed basal ration. However, the present study is one of the few, where it was possible to mitigate noxious emissions of dairy cows by feeding a tannin rich feed supplement without concomitant negative impact on the animal’s performance

Increasing the proportion of hazel leaves in the diet of dairy cows reduced methane yield and excretion of nitrogen in volatile form, but not milk yield

Various feeds for ruminants have been identified that help to mitigate the greenhouse gas methane. However, even when there has been success in suppressing absolute methane emissions, intake, digestibility, and performance often decline in parallel. Ideal dietary levels of effective feeds would reduce methane production without affecting performance-related variables. Such favorable associative effects have been demonstrated in vitro by combining a high-quality forage with plants rich in phenols. In the present study, the tannin-rich leaves of hazel (Corylus avellana) gradually replaced (from 0 to 820 g/kg) a high-quality forage (dried alfalfa) in 20 types of experimental pellets fed to 20 mid-to-late lactating cows. Additionally, the cows were fed a mixed basal ration and some concentrate. The proportion of hazel in the 20 complete diets ranged from 0 to 400 g/kg dry matter. After 14 days of adaptation, 8 days were used for intensive sampling of feces (including markers for determining digesta retention time), urine, and milk. In addition, cows stayed for 2 days in open-circuit respiration chambers. Hazel leaves reduced the feed intake only slightly. Digestibility declined and mean digesta retention time was prolonged with increasing hazel proportion, likely due to the lower feeding value of the hazel leaves compared to the alfalfa. As aimed for, there were no significant effects on energy-corrected milk yield, body energy, and body N retention with increasing hazel intake, even though methane emission clearly declined in absolute term and per unit of digestible organic matter and tended to decrease per unit of energy corrected milk. In addition, increasing hazel proportions strongly shifted N excretion from urinary N (which declined from about 300 to 100 g/kg N intake) to fecal N. This could also be anticipated from the sharp decline in milk urea concentration (from about 35 to 10 mg/dL). In conclusion, hazel leaves as a feed supplement for dairy cows showed a high palatability within 3 weeks of feeding in dairy cows and great potential to mitigate emissions of methane and nitrogen in volatile form at maintained production levels. No favorable associative dosage effects seem to exist when combining tannin-rich hazel leaves with the high-quality forage alfalfa in a different proportions to a mixed basal ration. However, the present study is one of the few, where it was possible to mitigate noxious emissions of dairy cows by feeding a tannin rich feed supplement without concomitant negative impact on the animal’s performance

Dose-response effects of woody and herbaceous forage plants on in vitro ruminal methane and ammonia formation, and their short-term palatability in lactating cows

Plant secondary compounds (PSC) are prevalent in many woody, temperate-climate plant species and play a crucial role in dietary attempts to mitigate methane emissions in ruminants. However, their application requires sufficient palatability and feeding value. In the present study, leaves from silver birch (Betula pendula), hazel (Corylus avellana), blackcurrant (Ribes nigrum), green grape vine (Vitis vinifera) and the herbs rosebay willow (Epilobium angustifolium) and wood avens (Geum urbanum) were tested in various doses with the Hohenheim gas test method in vitro and their short-term palatability in dairy cows. For the palatability experiment, the plants were pelleted with lucerne in different proportions to obtain the same phenol content, but realised contents differed from expected contents. The pellets were provided separately from a mixed basal ration (0.4 : 0.6) to each cow, in a randomised order, for 3 days per plant. All plants mitigated in vitro methane and ammonia formation, often in a linear dose response. These levels of effects differed among plants. Significant effects were observed at 100 (hazel, rosebay willow) to 400 g/kg of plant material. The test plants had a lower feeding value than the high-quality basal diet. This was indicated by in vitro organic matter digestibility, short-chain fatty acid formation and calculated contents of net energy of lactation. Simultaneously, the linear depression of ammonia formation indicated a dose-dependent increase of utilisable CP. Only blackcurrant and birch were less preferred to lucerne. However, this aversion subsided on day 3 of offer. The rosebay willow pellets had the highest phenol content but were not the least palatable. Accordingly, PSC may not be the main determinants of palatability for the plants tested. Plants did not differ significantly in their short-term effects on milk yield and composition, and all of the plants substantially reduced milk urea content. Overall, the results suggest that hazel and vine leaves, and rosebay willow and wood avens herbs should be tested for their potential to mitigate methane and N emissions in vivo

Behavioural responses related to increasing core body temperature of grazing dairy cows experiencing moderate heat stress

Exposure to direct solar radiation, high ambient temperature, lack of wind movement, coupled with own metabolic heat production, makes grazing dairy cows vulnerable to heat stress. In pastures, it would be beneficial to monitor heat stress by observable changes in behaviour. We hypothesised that grazing dairy cows exhibit behavioural changes due to increasing heat load in temperate climate. Over two consecutive summers, 38 full-time grazing Holstein dairy cows were investigated in 12 experimental periods of up to 3 consecutive days where the cows were repeatedly exposed to various levels of moderate heat load determined by the comprehensive climate index (CCI). The CCI defines the ambient climate conditions, combining air temperature, relative humidity, solar radiation and wind speed. Vaginal temperature (VT) was automatically measured as an indicator of heat stress. In addition, as a less invasive method, we investigated if reticular temperature (RET) can be indicative of heat stress on pastures. Walking activity, lying-, feeding, and ruminating durations were recorded continuously with sensors. Respiration rate (RR), proximity to and competition at the water trough, social licking, self-licking, inter-individual distance, and fly intensity were directly observed. Data were analysed in the morning (0900–1100 h) and during the hottest time of day when cows were on pasture (1230–1430 h). The VT and RET showed similar patterns in relation to the CCI, suggesting that RET can be suitable for continuous monitoring of heat stress on pastures. In the morning, the cow’s VT and RET did not relevantly react to the CCI. During the period 1230–1430 h, the cow’s mean VT (mean vaginal temperature (VTMEAN); range: 37.7–40.3 °C) and mean RET (mean reticular temperature; range: 37.0–41.1 °C) were positively related to the mean CCI (mean comprehensive climate index) in this period (mean ± SD: 25.9 ± 5.71 °C). For cows with greater VTMEAN, an increased mean RR and decreased durations of walking, lying, feeding, and ruminating were found. These cows were also more likely to be in proximity to the water trough and to have small inter-individual distances. Changes in these traits seem to reflect behavioural adaptations to heat stress in a temperate climate and could be used to detect the heat stress in individual dairy cows on pastures

Immediate effect of Acacia mearnsii tannins on methane emissions and milk fatty acid profiles of dairy cows

The effects of dietary supplements for modifying cattle digestion and metabolism are typically measured after one or more weeks of adaptation. Consequently, how quickly the effects occur remains unknown. The long-term efficacy of Acacia mearnssii bark tannins (Acacia) on methane mitigation has been previously demonstrated. The present study, therefore, investigated the time it took for the extract to affect methane emissions and milk fatty acid profiles. Twenty lactating Brown Swiss dairy cows, categorized as 10 low- and 10 high methane emitters (average difference in methane yield: 0.10 of total), were housed in respiration chambers for 4 days. A control diet consisting of a mixed ration supplemented with grass pellets and concentrate pellets was fed initially (Day 0). The original pellets were then replaced with pellets containing 141 g Acacia/kg, providing 30 g Acacia/kg of dietary dry matter (DM) (Days 1–3). Methane emissions were measured every 10 min and gas chromatography was used to analyze individual fatty acids from daily milk samples. A significant decline in methane production was detected 20 min after starting supplementation, with methane production (g/day) and methane yield (g/kg DM intake) decreasing in a linear fashion from Day 0 to Day 3 by up to proportionately 0.18 and 0.16, respectively. Additionally, changes in proportions of various milk fatty acids occurred within 3 days of Acacia feeding. Using stepwise multiple regression analysis, several milk fatty acids were identified as being related to methane emissions. Applicable equations from the literature also showed relationships to methane emissions of high and low emitters as well as to the Acacia diet effect on methane emissions. The equations with close relationships all included minor and nondietary milk fatty acids like odd-chain fatty acids. These specific fatty acids originate from rumen microbial activity. In conclusion, A. mearnsii extract is an immediately acting methane mitigating supplement. Certain milk fatty acids are related to methane emission in dairy cows and may assist in determining whether and when tanniferous supplements will act against enteric methane formation

Effects of Acacia mearnsii added to silages differing in nutrient composition and condensed tannins on ruminal and manure-derived methane emissions of dairy cows

ABSTRACT: This study investigated the effects of acacia (extract of Acacia mearnsii) and sainfoin (Onobrychis viciifolia) as condensed tannin (CT)-rich sources on ruminal and manure methane (CH4) emissions in comparison with non-CT silages characterized by different contents of the cell wall and water-soluble carbohydrates. In a 3 × 6 incomplete Latin square design, 30 Holstein cows (63 ± 23 d in milk; mean ± SD; 33.8 ± 7.6 kg of milk per day, body weight 642 ± 81 kg) were provided with ad libitum access to 1 of 6 total mixed rations comprising 790 g of silage and 210 g of concentrate per kilogram of dry matter (DM). The silages were either rich in sainfoin [neutral detergent fiber (NDF): 349 g/kg of DM], perennial ryegrass (NDF: 420 g/kg of DM), or red clover (NDF: 357 g/kg of DM). Each silage was supplemented with 20 g/kg (of total diet DM) of acacia or straw meal. Feed intake and milk yield were recorded daily. Milk composition and ruminal fluid characteristics and microbiota were analyzed. The individual ruminal CH4 production was determined using the GreenFeed system, and CH4 emissions from the manure of cows fed the same diets were measured in a parallel experiment over 30 d at 25°C using a dynamic flux chamber. The CT sources did not reduce CH4 yield or emission intensity. Acacia reduced milk production (from 26.3 to 23.2 kg/d) and DM intake (from 19.7 to 16.7 kg/d) when supplemented with ryegrass, and both CT sources reduced the milk protein content and yield. Acacia supplementation and ryegrass silage reduced the ruminal acetate:propionate ratio. Furthermore, during acacia treatment, the abundance of Methanobrevibacter archaea tended to be lower and that of Thermoplasmata was higher. Acacia reduced the CH4 emissions from manure for the ryegrass group by 17% but not for the sainfoin and clover groups. Feeding sainfoin silage resulted in the lowest manure-derived CH4 emissions (−47% compared with ryegrass). In conclusion, acacia reduced ruminal CH4 production by 10%, but not emission intensity, and the mitigation effect of sainfoin depended on the silage to which it was compared. Because mitigation was partially associated with animal productivity losses, careful evaluation is required before the implementation of tanniferous feeds in farm practice