Effects on feed intake, milk production, and methane emission in dairy cows fed silage or fresh grass with concentrate or fresh grass harvested at early or late maturity stage without concentrate.

The objective of the study was to quantify the effects on dry matter intake (DMI), nutrient digestibility, gas exchange, milk production, and milk quality in dairy cows fed fresh grass harvested at different maturity stages. Sixteen Danish Holstein cows in mid-lactation were divided into 4 blocks and used in 4 incomplete 4 × 2 Latin squares with 2 periods of 21 d. The cows received 1 of 4 treatments in each period, resulting in 8 cows per treatment, as follows: grass-clover silage supplemented with 6 kg/d concentrate pellets (SILc), fresh grass harvested at late maturity stage supplemented with 6 kg/d concentrate pellets (LATc), fresh grass harvested at late maturity stage (LAT), and fresh grass harvested at early maturity stage (ERL). The cows were housed in tiestalls and milked twice daily. The cows had ad libitum access to the forage, and concentrate pellets were divided into equal amounts and fed separately in the morning and afternoon. Fecal samples were collected to determine apparent total-tract digestibility, and samples of rumen fluid were collected for determination of short chain fatty acid composition. Halters were used for measuring eating and rumination time. Gas exchange was measured in open-circuit respiration chambers. Total DMI was higher in LATc and ERL (16.9 ± 0.45 and 15.5 ± 0.39 kg/d, respectively) compared with LAT (14.1 ± 0.42 kg/d). Relative to SILc, cows fed fresh grass experienced a convex pattern in DMI during the experiment. The changes in DMI were related to changes in leaf to stem ratio, fiber concentration, and organic matter digestibility determined in vitro in samples of the fresh grass harvested throughout the experiment. The apparent total-tract digestibility of organic matter was higher in SILc and LAT compared with LATc. Methane yield was lower for LATc compared with LAT (19.5 ± 0.61 vs. 22.6 ± 0.55 g of CH4/kg of DMI), and was not different between LAT and ERL. Compared with LAT, milk yield was higher for ERL (21.1 ± 1.14 vs. 23.4 ± 1.11 kg/d) and energy-corrected milk (ECM) yield was higher for LATc (21.5 ± 0.99 vs. 25.3 ± 1.03 kg/d). We detected no differences in milk or ECM yield between SILc and LATc. Milk protein yield was higher and milk fat concentration was lower in LATc compared with LAT. The fatty acid percentages of ∑C4-C14:1 and ∑C16 in milk were higher for SILc compared with LATc, signifying pronounced de novo synthesis. The n-6:n-3 ratio in milk fatty acids was lower for SILc and LAT compared with LATc, indicating improved nutritional quality for SILc and LAT. However, retinol concentration in milk was lower in SILc compared with all other treatments. The study implies that feeding silage instead of fresh grass has no effect on DMI, ECM yield, or CH4 yield, and that concentrate supplementation can increase milk production, affects milk quality, and reduces the effect on climate, whereas feeding less mature grass increases DMI and milk yield, but has no effect on CH4 yield.

Response to different sources of vitamin E orally injected and to various doses of vitamin E in calf starter on the plasma vitamin E level in calves around weaning.

Calves often face a lower plasma vitamin E level than the recommended level (3 µg/ml for adult cows) after weaning, a level which has been related to a good immune response. Two experiments were performed to determine the most effective source and level of vitamin E to be included in a calf starter to maintain the plasma vitamin E level above the recommended level after weaning. Experiment 1 (Exp 1) and experiment 2 (Exp 2) included a total of 32 and 40 calves, respectively, from 2 weeks before weaning until 2 weeks after weaning. In Exp 1, calves were orally injected a daily dose of different vitamin E sources including, no α-tocopherol (0 dose; Control), 200 mg/d of RRR-α-tocopherol (ALC), 200 mg/d of RRR-α-tocopheryl acetate (ACT), or 200 mg/d of all-rac-α-tocopheryl acetate (SYN). In Exp 2, a dose response study was carried out with 0, 60, 120, and 200 mg/kg of ALC in a pelleted calf starter. Final BW (100 ± 16 and 86 ± 11 kg) and average daily gain (956 ± 303 and 839 ± 176 g/d in Exp 1 and 2, respectively; mean ± SD) were unaffected by either source or level of α-tocopherol. In Exp 1, the plasma RRR-α-tocopherol level was affected by α-tocopherol source (P < 0.001), week (P < 0.001), and interaction between them (P < 0.001). At weaning time, the plasma RRR-α-tocopherol was 2.7, 2.1, 1.1, and 0.8 µg/ml in ALC, ACT, SYN, and Control, respectively. In Exp 2, the plasma α-tocopherol level was affected by ALC dose (P = 0.04), week (P < 0.001), and a tendency for an interaction between them was observed (P = 0.06). At weaning, a 36, 31, and 28% reduction in plasma α-tocopherol level was observed compared to the beginning of the experiment with 0, 60, and 120 mg/kg of ALC, respectively; however, with 200 mg/kg of ALC, a 9% increase in the plasma α-tocopherol level was observed. In addition, 200 mg/kg of ALC was able to maintain plasma α-tocopherol after weaning higher than the recommended level. The results showed that the ALC was the most efficient source of α-tocopherol supplementation to be used in a calf starter. In addition, the 200 mg/kg of ALC in the calf starter was the only effective dose to maintain the postweaning plasma vitamin E concentration at the recommended level after weaning and α-tocopherol similar to that observed before weaning.

Fatty acid profile of phospholipids and sphingomyelin in milk and regulation of sphingomyelin synthesis of mammary glands in cows receiving increasing levels of crushed sunflower seeds.

The objective of this study was to investigate the effect of increasing dietary supplementation of crushed sunflower seed (CSS) in the diet of dairy cows on the fatty acid (FA) composition of phospholipids and sphingomyelin in milk, and on mammary transcription of genes that are important for sphingomyelin de novo synthesis. Four groups of 6 cows received diets supplemented with CSS at 0% (control), or 5, 10, or 15% of dry matter for a 5-wk experimental period. Milk samples and mammary biopsies were collected at the end of the experiment. Phospholipid concentration in milk fat decreased linearly with CSS supplementation. Sphingomyelin concentration in milk fat was unaffected by CSS supplementation. Daily yield of phospholipids decreased linearly with CSS supplementation. Daily yield of sphingomyelin was not significantly affected. The CSS supplementation linearly increased the proportion of monounsaturated FA in milk phospholipids. The major isomer incorporated into phospholipids was C18:1 (n-9 cis), which showed a linear increase with CSS supplementation. The C22:0 proportion in sphingomyelin increased linearly with CSS supplementation and constituted between 15.2 to 25.4% of total FA in sphingomyelin. However, CSS supplementation linearly decreased C23:0 sphingomyelin. Mammary transcription of serine palmitoyl transferase, long chain subunit 1 and subunit 2, the rate-limiting enzymes in ceramide synthesis, showed a linear decrease with increasing CSS supplementation. In conclusion, the data showed that dietary supplementation of CSS linearly increased the proportion of unsaturated FA and monounsaturated FA in milk phospholipids with no effect on phospholipid concentration. In addition, CSS supplementation linearly decreased n-3 polyunsaturated fatty acid proportion in sphingomyelin. The results further showed that mammary transcription of important genes for sphingomyelin de novo synthesis is regulated by lipid supplementation.

Bioavailability of α-tocopherol stereoisomers in lambs depends on dietary doses of all-rac- or RRR-α-tocopheryl acetate.

When supplementing lamb diets with vitamin E, an equivalence factor of 1.36 is used to discriminate between RRR-α-tocopheryl acetate and all-rac-α-tocopheryl acetate. However, more recent studies suggest a need for new equivalence factors for livestock animals. The current study aimed to determine the effect of RRR- and all-rac-α-tocopheryl acetate supplementation on α-tocopherol deposition in lamb tissues. A total of 108 Rasa Aragonesa breed lambs were fed increasing amounts of all-rac-α-tocopheryl acetate (0.25, 0.5, 1.0 and 2.0 g/kg compound feed) or RRR-α-tocopheryl acetate (0.125, 0.25, 0.5 and 1.0 g/kg compound feed) by adding them to a basal diet that contained 0.025 g/kg feed of all-rac-α-tocopheryl acetate as part of the standard vitamin and mineral mixture. The diets were fed for the last 14 days before slaughtering at 25.8±1.67 kg BW. Within 20 min after slaughter samples of muscle, heart, liver, brain and spleen were frozen at -20°C until α-tocopherol analysis. Increased supplementation of either vitamin E sources led to a significant increase (P < 0.001) in α-tocopherol concentration in all tissues studied. The tissue with the highest α-tocopherol concentration was the liver followed by spleen, heart and muscle. At similar supplementation levels (0.25, 0.50 and 1.0 g/kg compound feed), α-tocopherol content in the selected tissues was not affected by α-tocopherol source. However, the ratios between RRR- and all-rac-α-tocopheryl acetate increased with the increasing α-tocopherol supplementation (at 0.25 and 1.0 g/kg compound feed), from 1.06 to 1.16 in muscle, 1.07 to 1.15 in heart, 0.91 to 0.94 in liver and 0.98 to 1.10 in spleen. The highest relative proportion of Æ©2S (sum of SSS-, SSR-, SRS- and SRR-α-tocopherol)-configured stereoisomers was found in the liver of lambs supplemented with all-rac-α-tocopheryl acetate accounting for up to 35 to 39% of the total α-tocopherol retained, whereas the proportion of Æ©2S-configured stereoisomers in the other tissues accounted for <14%. Increasing all-rac-α-tocopheryl acetate supplementation was also found to affect the 2R-configured stereoisomer profile in muscle, heart and spleen with increasing proportions of RRS-, RSR- and RSS- at the cost of RRR-α-tocopherol. In all tissues, the relative proportion of all non-RRR-stereoisomers in lambs receiving RRR-α-tocopheryl acetate was lower than RRR-α-tocopherol. These results confirm that the relative bioavailability of RRR- and all-rac-α-tocopheryl acetate is dose- and tissue-dependent and that a single ratio to discriminate the two sources cannot be used.

Plasma transport of ergocalciferol and cholecalciferol and their 25-hydroxylated metabolites in dairy cows.

In cattle, there are 2 significant forms of vitamin D: ergocalciferol (ERG) from fungi on roughage and cholecalciferol (CHO) from vitamin supplements or endogenous synthesis in the skin. The hypothesis of the present study is that vitamin D from the 3 sources is transported in different plasma fractions in the body. This is hypothesized to explain the lower efficiency of ERG compared to CHO in securing a sufficient plasma status of 25-hydroxyvitamin D and explain the inefficient excretion of dietary CHO into milk compared to endogenous CHO. Twenty vitamin D-depleted cows were assigned to 5 treatments: D2, housed indoor and fed 625-µg/d (25.000 IU) ERG; D3, housed indoor and fed 625-µg/d CHO; D2+D3, housed indoor and fed 625-µg/d ERG and 625-µg/d CHO; SUN, let out for daily pasture to facilitate CHO synthesis from sunlight; and D2+SUN, fed 625-µg/d ERG and let out for daily pasture. Blood samples were taken twice weekly and plasma fractionated by ultracentrifugation into 3 fractions: light lipoprotein (LLP), heavy lipoprotein (HLP), and protein and analyzed for content of ERG and CHO and their liver derived metabolites 25-hydroxyergocalciferol (25ERG) and 25-hydroxycholecalciferol (25CHO), respectively. Liver biopsies were taken on the last day of the study to asses gene expression related to vitamin D metabolism. During 4 wk of study, the vitamin D status in plasma increased to 19.3 to 22.8 ng/mL 25ERG in ERG-treated cows with the highest concentration in D2 (P ≤ 0.05) and to 25.0 to 33.4 ng/mL 25CHO in pasture or CHO-treated cows with the highest concentration in SUN (P ≤ 0.01). In plasma fractions, CHO was mainly found in the HLP fraction, whereas 25CHO was almost exclusively found in the protein fraction, probably due to its reported high binding affinity to vitamin D-binding protein. About 70% to 90% of 25ERG was found in the protein fraction and the remaining 25ERG was found in HLP, whereas ERG was found in both HLP and LLP fractions. In liver tissue, the expression of vitamin D-25-hydroxylase was lower in D2+D3 (P ≤ 0.05) and SUN (P ≤ 0.05) than that in the remaining groups, and the vitamin D receptor was expressed in the liver to a larger extent in D2+SUN than that in D2+D3 (P ≤ 0.05) and SUN (P ≤ 0.05). In conclusion, different plasma transport mechanisms may explain the lower physiological efficiency of ERG compared to CHO in securing the vitamin D status in plasma but do not explain the lower efficiency of synthetic CHO compared to endogenous CHO from sunlight or UV light in securing a high CHO content in milk.

Status of vitamins E and A and ß-carotene and health in organic dairy cows fed a diet without synthetic vitamins.

Synthetic vitamin supplementation is not consistent with organic production, so it is important to investigate whether dairy cows can maintain their health and production without synthetic vitamins being added to their diet. In basic dairy cow diets, provitamin A (ß-carotene) and vitamin E are mainly found in pasture and in grass and legume silages, but the concentrations are highly variable. This study compared the vitamin status and health of cows without synthetic vitamin supplementation (NSV group) with control cows (CON group) fed synthetic vitamins according to Swedish recommendations (600 IU of vitamin E and 80,000 IU of vitamin A per cow per day) to investigate whether dairy cows can fulfill their requirements of vitamins A and E without supplementation with synthetic vitamins. Vitamin concentrations in blood plasma and milk, health, fertility, milk yield, and milk composition were measured in Swedish Holstein cows (n=28) during 2 complete lactations. All cows were fed a 100% organic diet containing grass-legume silage, cold-pressed rapeseed cake, peas, cereal grains, and minerals. Blood samples were collected from each cow 3 wk before expected calving, at calving, and 3 wk, 3 to 5 mo, and 7 to 9 mo after calving. Samples of colostrum were taken and milk samples were collected 4d after calving and at the same time as the 3 blood samplings after calving. The only difference in vitamin status between groups was found in colostrum in yr 1, when CON cows tended to have a higher concentration of α-tocopherol, and their ß-carotene concentration was higher compared with NSV cows. The NSV cows tended to have more cases of mastitis than CON cows in yr 2. Within the NSV group, fewer cows were healthy and more cases of mastitis were observed in yr 2 than in yr 1. The groups did not differ in production parameters. In conclusion, the vitamin status in blood and milk of the studied cows indicated that cows in organic dairy production can fulfill their requirements of vitamins A and E without any supplementation of synthetic vitamins, except at the time around calving, when the requirements are high. However, the impaired health of NSV cows in yr 2 may indicate a long-term negative health effect in cows fed no synthetic vitamins.

Effect of short-term versus long-term grassland management and seasonal variation in organic and conventional dairy farming on the composition of bulk tank milk.

Bulk tank milk from 28 dairy farms was sampled every second month for 2 yr to assess the effects of grassland management, production system and season on milk fatty acid (FA) composition, concentrations of fat-soluble vitamins, Se, and milk sensory quality. Grassland management varied in terms of time since establishment. Short-term grassland management (SG) was defined as establishment or reseeding every fourth year or more often, and long-term grassland management (LG) was defined as less frequent establishment or reseeding. Fourteen organic (ORG) dairy farms with either short-term or long-term grassland management were paired with 14 conventional (CON) farms with respect to grassland management. Within ORG farms, SG farms differed from LG farms in herbage botanical composition, but not in concentrate FA concentrations, dry matter intake, or milk yield. Within CON farms, herbage composition, concentrate FA concentrations, dry matter intake, and milk yield showed no or insignificant variations. The ORG farms differed from CON farms in herbage botanical composition, concentrate FA concentrations, concentrate intake, and milk yield. Compared with ORG-LG farms, ORG-SG farms produced milk fat with higher proportions of C10:0 and C12:0 associated with higher herbage proportions of legumes (Fabaceae) and lower proportions of other dicotyledon families. Compared with milk from CON farms, milk fat from ORG farms had higher proportions of most saturated FA and all n-3 FA, but lower proportions of C18:0 and C18:1 cis-9 associated with higher forage proportion and differences in concentrations of FA in concentrates. Compared with the outdoor-feeding periods, the indoor feeding periods yielded milk fat with higher proportions of most short-chain and medium-chain FA and lower proportions of most C18-FA associated with grazing and higher forage proportions. Milk concentrations of α-tocopherol and ß-carotene were lower during the grazing periods. Inclusion of fishmeal in organic concentrates may explain higher Se concentrations in organically produced milk. Milk sensory quality was not affected in this study. In conclusion, grassland management had minor effects on milk composition, and differences between ORG farms and CON farms may be explained by differences in concentrate intake and concentrate FA concentrations. Milk produced on ORG farms versus CON farms and milk produced during the outdoor versus indoor feeding periods had potential health benefits due to FA composition. In contrast, the higher milk-fat proportions of saturated FA in milk from ORG farms may be perceived as negative for human health.

Colostrum and milk production of sows is affected by dietary conjugated linoleic acid.

The present experiment was conducted to investigate dietary effects of conjugated linoleic acid (CLA) on sow traits related to piglet survival and growth performance. A total of 23 gestating sows were fed either a standard lactation diet (control diet [CON]) or the CON supplemented with 1.3% CLA (cis-9, trans-11 and trans-10, cis-12) from day 108 of gestation until weaning (4 wk after parturition) to evaluate whether dietary CLA affects the yield and composition of colostrum, time for initiation of milk production, and sow milk yield. Sows fed CLA tended to produce more colostral fat (6.3 vs. 5.2%, respectively; P = 0.10) than CON sows whereas contents of lactose, protein, and dry matter were similar in the two groups. Sows fed CLA tended to produce less colostrum than CON sows (409 vs. 463 g/piglet, respectively; P = 0.07) as predicted by the piglet rate of gain from 0 to 24 h (58 vs. 97 g/piglet, respectively; P = 0.07). The piglet mortality during the first week of lactation tended to be higher for sows fed CLA than for CON sows (6.8 vs. 2.3%, respectively; P = 0.10), and the number of piglets that died or were moved to others sows to ensure survival during the first week was more than double in the CLA group (17.6 vs. 7.8%, respectively; P = 0.04). Copious milk production was initiated 33 h (CLA) and 34 h (CON) after parturition and was not affected by dietary treatments (P = 0.41). Sow milk yield was improved by the CLA treatment from days 7 to 14 of lactation (P = 0.03). Weight at birth (1.40 kg for both groups; P = 0.98) and at weaning [8.2 kg (CLA) and 8.0 kg (CON); P = 0.52] was not statistically different. In conclusion, colostrum yield was inhibited but milk yield was stimulated by dietary inclusion of cis-9, trans-11 and trans-10, cis-12 CLA and indicates that sow productivity may be improved by using different fatty acids for transition and lactating sows.

Vitamin D2 impairs utilization of vitamin D3 in high-yielding dairy cows in a cross-over supplementation regimen.

Vitamin D exists in 2 forms that are important regarding vitamin D status and supply in cattle: vitamin D(2) (D(2)) and vitamin D(3) (D(3)). To become physiologically active, both D(2) and D(3) must undergo 25-hydroxylation in the liver. The resulting 25-hydroxyvitamin D(2) [25(OH)D(2)] and 25-hydroxyvitamin D(3) [25(OH)D(3)] are measured as indicators of the physiological vitamin D status of cattle. The study used 14 Danish Holstein cows housed without access to sunlight. The cows were orally administered 250 mg (1.0 × 10(7)IU) of D(2) and D(3) in a cross-over design with 2 treatment groups and 2 study periods, rendering 4 treatments when carryover effects were taken into account: D(2) given first, D(2) given last after D(3), D(3) given first, and D(3) given last after D(2). Two weeks elapsed between the treatment in the first study period and the treatment in the second study period. Blood samples were collected 0, 3, 6, 14, 17, 20, 23, 26, 40, 48, 70, 94, 166, and 214 h after providing the oral bolus of vitamin to the cows. Comparisons between plasma levels of the metabolites D(2), D(3), 25(OH)D(2), and 25(OH)D(3) over time were made by comparing areas under the plasma concentration curves. Oral administration of D(3) increased plasma D(3) (182.6±17.1 ng/mL; mean ± SEM) and 25(OH)D(3) (103.5±10.0 ng/mL) more efficiently than oral administration of D(2) increased plasma D(2) (49.1±32.6 ng/mL) and 25(OH)D(2) (27.9±2.1 ng/mL). The D(3) given after an oral dose of D(2) was less efficient for increasing plasma concentrations of 25(OH)D(3) (61.2±12.0 ng/mL) compared with D(3) given without previous D(2) administration (103.5±10.0 ng/mL), whereas the plasma concentrations of D(3) itself were the same when given first (182.6±17.1 ng/mL) as when given after D(2) (200.0±123.9 ng/mL). The same occurred for plasma concentrations of D(2) metabolites both if D(2) was given first (49.1±32.6 ng/mL) and after D(3) (54.7±7.7 ng/mL). In conclusion, D(3) given after D(2) is less efficient at increasing the plasma status of 25(OH)D(3) than D(3) given without previous D(2) administration.

Administration of RRR-α-tocopherol to pregnant mares stimulates maternal IgG and IgM production in colostrum and enhances vitamin E and IgM status in foals.

This study assessed the effect of a vitamin E supplement given to pregnant mares on immunoglobulins (Ig) levels in foals. In addition, the fatty acid (FA) content and composition of the mares' milk was assessed. Milk α-tocopherol concentrations were compared between pregnant Danish Warmblood mares (n = 17) given a daily oral supplement of 2500 international units (IU) RRR-α-tocopherol in the last 4 weeks of pregnancy and a group of unsupplemented mares (n = 17) receiving 170-320 IU vitamin E daily originating from the feed. Milk α-tocopherol was higher in supplemented mares (36.7, 12.4 and 9.8 µmol/l respectively) in relation to control mares (13.1, 6.4 and 5.8 µmol/l on days 1, 2 and 3 respectively; p < 0.001). Milk IgG was higher on days 2 and 3 post-partum (PP) in supplemented mares (1.03 and 0.73 mg/ml respectively) in relation to control mares (0.79 and 0.56 mg/ml respectively; p < 0.05). Milk IgM was higher on days 2 and 3 post-partum (PP) in supplemented mares (0.19 and 0.17 mg/ml) in relation to control mares (0.13 and 0.11 mg/ml respectively; p < 0.05). Plasma α-tocopherol in foals was higher from supplemented mares on days 1, 2 and 3 (5.7, 14.8 and 19.2 µmol/l respectively) in relation to foals from control mares (3.6, 6.1 and 7.6 respectively; p < 0.001). Foal plasma IgM was higher from supplemented mares on day 3 (0.50 mg/ml) in relation to foals from control mares (0.32 mg/ml; p < 0.001). The total FA content in milk was highest on day 1 (21.6 g FA/kg milk) in relation to days 2 and 3 (13.6 and 13.5 g FA/kg milk respectively; p < 0.001). In conclusion, a daily oral supplement of 2500 IU RRR-α-tocopherol increased α-tocopherol content in mare milk and foal plasma, IgG and IgM in mare milk and IgM in foal plasma.

Reproductive performance and bone status markers of gilts and lactating sows supplemented with two different forms of vitamin D.

In swine nutrition, little is known about the vitamin D requirements for reproductive processes and bone health. Consequently, the vitamin D recommendation for sows during gestation and lactation is not based on scientific reports. The current study was undertaken to obtain information on the dose-response pattern of 2 vitamin D sources, the commonly used cholecalciferol, called vitamin D(3), and a newly developed Hy.D product (25-hydroxycholecalciferol). In Exp. 1, a total of 160 gilts were randomly assigned from the first estrus until d 28 of gestation to dietary treatments containing 4 concentrations of 1 of the 2 different vitamin D sources [200, 800, 1,400, and 2,000 IU/kg of vitamin D from cholecalciferol or corresponding doses of 5, 20, 35, and 50 microg/kg of feed from 25(OH)D(3) (Hy.D)]. In a concurrent experiment, the same 8 dietary treatments were provided to 160 multiparous sows from the first day of mating until weaning. Plasma concentrations of 25(OH)D(3) were influenced by a dose x form interaction (P < 0.001); furthermore, plasma 25(OH)D(3) concentrations were influenced by the lactation state of the sows. Irrespective of the dietary dose and form of vitamin D provided to the sows, very little vitamin D was transferred to the progeny. Reproductive performance was not influenced by dietary vitamin D treatments, except for a decreased number of stillborn piglets (P = 0.03, SE = 0.40) with the larger doses of vitamin D (1,400 and 2,000 IU of vitamin D, resulting in 1.17 and 1.13 stillborn piglets per litter, respectively) compared with the smaller doses of vitamin D (200 and 800 IU of vitamin D, resulting in 1.98 and 1.99 stillborn piglets per litter, respectively). In the gilt trial, the ultimate strength of the bones (P = 0.01) and their content of ash (P = 0.02) were greater when vitamin D(3) was supplemented in doses larger than 800 IU, compared with the same amount of Hy.D supplementation. In the sow experiment, lactation day (P < 0.001), rather than dietary vitamin D, influenced the concentrations of osteocalcin and Ca as well as the activities of total alkaline phosphatase and bone alkaline phosphatase in plasma. Age of the suckling piglets affected their plasma bone health markers. In conclusion, at doses greater than 200 IU, Hy.D was more bioavailable than vitamin D(3) and, as such, could be considered an equivalent or even more advantageous source of vitamin D. In addition, a dietary dose of approximately 1,400 IU of vitamin D is recommended for reproducing swine. Irrespective of the dietary dose and form of vitamin D provided to the sows, very little vitamin D was transferred to the progeny.

Bio-discrimination of alpha-tocopherol stereoisomers in rearing and veal calves fed milk replacer supplemented with all-rac-alpha-tocopheryl acetate.

This study evaluated the biological discrimination of different alpha-tocopherol stereoisomers (i. e. RRR-, RRS-, RSR-, RSS- and the four 2S-alpha-tocopherols) from all-rac-alpha-tocopheryl acetate supplementation in milk replacer for rearing and veal calves respectively, in practical farming conditions. Two experiments were conducted. In experiment 1, six rearing calves were fed milk replacer supplemented with 80 mg/kg all-rac-alpha-tocopheryl acetate for a period of 9 weeks. The calves were supplied calf starter concentrate from 1 to 12 weeks. In experiment 2, six veal calves were fed milk replacer supplemented with 80 mg/kg all-rac-alpha-tocopheryl acetate for a period of 24 weeks. Blood samples were taken at the start and every 4 weeks until 12 weeks for rearing calves in experiment 1, and until slaughter (24 weeks) for veal calves in experiment 2. Liver, adipose, muscle, and brain samples were taken at slaughter of the six veal calves in experiment 2. The distribution of different alpha-tocopherol stereoisomers in feed, plasma, and tissues was analyzed. In both experiments, it was observed that RRR-alpha-tocopherol was the dominant stereoisomer in plasma and tissues. The average percentage of the RRR-alpha-tocopherol stereoisomer was 64 %, and 39 % of the total alpha-tocopherol in plasma for rearing and veal calves, respectively. The higher RRR-alpha-tocopherol stereoisomer proportion as percentage of the total alpha-tocopherol in rearing calves was related to higher dietary natural vitamin E intake. Other 2R-alpha-tocopherol stereoisomers had lower utilization efficiency than RRR-alpha-tocopherol stereoisomer. 2S-alpha-tocopherol stereoisomers were basically not utilized by calves.

Supplementation of RRR-alpha-tocopheryl acetate to periparturient dairy cows in commercial herds with high mastitis incidence.

Dietary vitamin E supplementation of dairy cows around calving has been associated with improved udder health. However, few studies have been performed in Europe and in commercial dairy herds. Therefore, the main aim of the study was to evaluate whether extra daily dietary supplementation of 1,610 mg of alpha-tocopherol, in the form of RRR-alpha-tocopheryl acetate, to dairy cows around calving could improve the udder health in commercial herds with a high incidence of veterinary-treated clinical mastitis. In addition, the effects of supplementation on other cow diseases, fertility, milk production, culling, and stillbirth were also studied. Cows in 21 herds in southeast Sweden were assigned to 1 of 2 groups, 1) daily supplementation with 1,610 mg of RRR-alpha-tocopherol from 4 wk before to 2 wk after calving (n = 196), or 2) no extra supplementation (n = 203), on top of the normal diet containing average vitamin E supplementation (on average, 386, 664, and 957 mg/d to cows at 1 mo prior to calving, at calving, and at 15 d after calving, respectively). Multivariable generalized linear mixed models were used for statistical analyses of the effects of supplementation on the cumulative incidence risk of veterinary-treated clinical mastitis and of veterinary-treated diseases other than mastitis within 1 and 2 mo after calving, culling (due to udder health or other reasons) within 2 and 9 mo after calving, the risk of stillbirth or calf death within 24 h after calving, time from calving to first insemination, number of inseminations per service period, and cow composite natural logarithm of somatic cell count and daily milk production at the first monthly testing after calving. A significant effect of supplementation was observed only for stillbirth or calf death within 24 h after birth, which was significantly lower in the supplemented group. The reasons for this finding require further study.

Influence of supplementation of all-rac-alpha-tocopheryl acetate preweaning and vitamin C postweaning on alpha-tocopherol and immune responses of piglets.

This study was designed to test whether dietary maternal supplementation of all-rac-alpha-tocopheryl acetate during lactation and dietary vitamin C supplementation after weaning could increase the alpha-tocopherol status pre- and postweaning and the immune responses of piglets postweaning. The experiment involved 12 crossbred sows that were fed increasing levels of all-rac-alpha-tocopheryl (70, 150, and 250 IU/kg, as-fed basis) during lactation. After weaning (d 28 of age), litters were divided into two groups that were supplemented with or without vitamin C (500 mg/kg of feed, as-fed basis). Milk and blood samples were obtained from the sows during lactation. Pigs were bled at 4, 16, 28, 35, 42, and 49 d of age. Liver, heart, muscle, and s.c. adipose tissues were collected (on 28, 35, 42, and 49 d of age) and analyzed for alpha-tocopherol. On the same days, alveolar macrophages of the lungs were collected, and analyzed for the concentration of alpha-tocopherol and its stereoisomer composition, fatty acid composition, and release of prostaglandin E2, leukotriene B4, and thromboxane B2. Increasing dietary all-rac-alpha-tocopheryl acetate concentration increased the concentration of alpha-tocopherol in plasma (P = 0.02) and milk (P = 0.007) of sows, and the sow milk concentrations of alpha-tocopherol and vitamin A were greater on d 2 of lactation than later on during lactation. The plasma concentration of alpha-tocopherol in piglets decreased from d 4 to later on during suckling (P < 0.001) and again as the postweaning period progressed (P < 0.001). When lipid-standardized, plasma alpha-tocopherol was increased in piglets of sows fed 250 IU of all-rac-alpha-tocopheryl acetate compared with other sow-groups (P = 0.005). At 28 d of age, alpha-tocopherol concentrations in tissues were increased with supplementation of the high dietary all-rac-alpha-tocopheryl acetate levels to the sows; however, after weaning, a decrease in alpha-tocopherol concentration in most tissues (except liver) was observed, but the decrease tended to be less in the muscle (P = 0.099) and adipose tissue (P = 0.11) of piglets suckling sows fed 150 and 250 IU of all-rac-alpha-tocopheryl acetate. Vitamin C supplementation after weaning increased liver alpha-tocopherol (P = 0.01) and serum immunoglobulin M concentration (P = 0.04), and vitamin C supplementation increased the proportion of the RRR-alpha-tocopherol (P = 0.03) at the expense of the RRS-stereoisomer form (P = 0.05) of alpha-tocopherol in alveolar macrophages of the piglets. In conclusion, this study on maternal all-rac-alpha-tocopheryl acetate and postweaning vitamin C supplementation suggests a nutritional strategy for increasing alpha-tocopherol status and immune responses of weaned piglets.

Ascorbic acid, alpha-tocopherol, and oregano supplements reduce stress-induced deterioration of chicken meat quality.

In order to ameliorate a negative effect of stress on meat quality characteristics, chickens were fed a diet supplemented with a combination of ascorbic acid (1,000 ppm) and alpha-tocopherol (200 ppm) or oregano (3%), which has a high content of antioxidants. Chickens were slaughtered by cervical dislocation in the stable (no stress) or after transport and electrical stunning at the slaughter plant (stress). Activities of antioxidative enzymes (catalase, superoxide dismutase, and glutathion peroxidase) in pectoralis major (PM), iliotibialis (IL), and liver were unaffected by supplementation. However, erythrocyte stability, which is a more complex model system for determining oxidative status, increased with ascorbic acid-alpha-tocopherol supplementation and tended to increase after oregano supplementation. In nonstressed birds, this improved antioxidative status was reflected in decreased TBA-reactive substances (TBARS) in PM and liver of ascorbic acid-alpha-tocopherol-supplemented chickens and likewise in liver from oregano-supplemented chickens compared to that of nonstressed control birds. However, postmortem temperature, pH, and water-holding capacity were not affected by supplementation. Drip loss from oregano-supplemented chickens showed increased protein oxidation in specific bands, but this did not relate to water-holding capacity or antioxidative status. When exposed to stress, the concentration of TBARS in the control animals increased in PM and IL. Ascorbic acid-alpha-tocopherol supplementation protected IL, and oregano supplementation protected PM from stress-induced increases in TBARS. This differential effect between muscles may indicate differences in protection mechanisms. In conclusion, ascorbic acid-alpha-tocopherol and oregano supplements to chickens protect against stress-induced increase in TBARS, in different muscles.

Manipulation of critical quality indicators and attributes in pork through vitamin E supplementation, muscle glycogen reducing finishing feeding and pre-slaughter stress.

The combination of a muscle glycogen reducing diet or a standard diet (control group) with normal (80 mg/kg) and high vitamin E levels (500 mg/kg) and exercise immediately prior to slaughter was used on 56 pigs to investigate the influence on meat quality indicators (pH and temperature) and attributes (drip loss, colour and Warner-Bratzler shear force). The drip loss was reduced in M. longissimus dorsi, M. biceps femoris and M. semimembranosus in pigs given the muscle glycogen reducing diet compared with the control groups, the greatest effect was seen in exercised pigs. These results can be explained by an early post mortem reduction in glycometabolism in pigs fed muscle glycogen reducing diets rather than by an increase in ultimate pH. Noticeably, high dietary vitamin E level increased muscle glycogen stores by about 10% on the day prior to slaughter but not on the day of slaughter in both dietary groups compared with the low dietary vitamin E level, which in fact reduced rather than improved the water-holding capacity, especially in pigs fed the standard diet.

Digestion of fat does not differ in growing pigs fed diets containing fish oil, rapeseed oil or coconut oil.

We studied the digestion of fat and fatty acids in diets containing oils with different fatty acid composition. Four barrows (initial weight 35 kg) were fitted with a simple T-cannula at the terminal ileum. Three wheat starch and fish meal-based diets were formulated to contain either 150 g fish oil, rapeseed oil or coconut oil/kg. A basal diet, which did not contain oil, was also prepared. The diets were fed according to a 4 x 4 Latin square design. Each experimental period comprised 5 d adaptation to the diets, 3 d fecal collection and 2 d digesta collection. The apparent ileal and fecal digestibilities of fat were relatively high (88 - 93%). The ileal digestibilities of total, saturated and monounsaturated fatty acids did not differ among the diets. However, the digestibilities of polyunsaturated fatty acids (PUFA) in the fish and rapeseed oil diets were higher (P < 0.05) than in the coconut oil diet. The ileal digestibilities of 18:1, 18:2 and 18:3 in the rapeseed oil diet ranged from 94 to 97%. The ileal digestion of the unsaturated long-chain fatty acids 20:5(n-3) and 22:6(n-3) in the fish oil diet was nearly complete (97 - 98%). Apparent fecal digestibilities of saturated fatty acids (76 - 89%) were lower than apparent ileal digestibilities (89 - 94%). The digestibilities of fat and fatty acids were relatively high when pigs were fed diets containing fish oil, rapeseed oil or coconut oil. There were few differences in the digestibilities of saturated, monounsaturated and PUFA in the fish oil, rapeseed oil or coconut oil diets.

Influence of supranutritional vitamin E and copper on α-tocopherol deposition and susceptibility to lipid oxidation of porcine membranal fractions of M. Psoas major and M. Longissimus dorsi.

Addition of 200 ppm all-rac-α-tocopheryl acetate to pig feed supplemented with 6% high-oleic rapeseed oil gave mitochondrial membranes, which had a lower rate of formation of free radicals as determined by ESR-spectroscopy using the spin-trapping technique. Addition of 175 mg/kg copper to the feed, with or without all-rac-α-tocopherol acetate addition was not pro-oxidative (or anti-oxidative). While these effects were similar for both the oxidative M. Psoas major (PM), and the glycolytic, M. Longissimus dorsi (LD), differences between muscles were characterised by a higher activity of ß-hydroxyacyl-coenzyme A-dehydrogenase (HAD) and citrate synthase (CS), and a lower activity of lactate dehydrogenase (LDH) in PM than in LD (p<0.001). The concentration of α-tocopherol in muscles, liver, and plasma was influenced by the α-tocopherol level in the feed (p<0.001). The concentration of fatty acids in microsomes was not influenced by dietary treatments, but was higher in PM than in LD. However, the total concentration of fatty acids in the mitochondria of PM was higher in pigs supplemented with all-rac-α-tocopheryl acetate.

Effects of dietary α-tocopheryl acetate supplementation on α-tocopherol deposition in porcine m. psoas major and m. longissimus dorsi and on drip loss, colour stability and oxidative stability of pork meat.

The effect of feeding supra-nutritional levels of α-tocopheryl acetate on its deposition in two porcine muscles of different metabolic rates (m. longissimus dorsi and m. psoas major) and the effect on meat quality (lipid oxidation, colour stability and drip loss) was studied. Pigs were fed a standard diet supplemented with three levels: 100, 200 and 700 mg/kg of α-tocopheryl acetate from the time of weaning to slaughter at 90kg live weight. Muscle α-tocopherol levels were linearly related to the logarithm of dietary α-tocopheryl acetate supplementation and the linear relationship was estimated for the two muscles. The levels of α-tocopherol in the two muscles differed by a parallel displacement with consistently higher α-tocopherol levels in m. psoas major compared to m. longissimus dorsi. Dietary α-tocopheryl acetate supplementation significantly reduced lipid oxidation as measured by thiobarbituric acid reactive substances (TBARS) in both raw and cooked meat during storage at 4 °C for 6 days. Drip loss and colour stability of raw muscles were not affected by dietary α-tocopheryl acetate levels, 100mg α-tocopheryl acetate/ kg feed resulted in sufficient α-tocopherol levels in muscles to ensure minimum drip loss and optimum colour stability.

Exocrine pancreatic secretions in growing pigs fed diets containing fish oil, rapeseed oil or coconut oil.

Two experiments were performed to study the effect of feeding diets containing oils with different fatty acid composition on exocrine pancreatic secretions in growing pigs using two different methods to collect pancreatic juice. In the first experiment, three barrows (initial weight 37 kg) were fitted with a pancreatic pouch re-entrant cannula. An isolated pouch was prepared where the pancreatic duct enters the duodenum. In the second experiment, also using three barrows (initial weight 32 kg), a catheter was inserted into the pancreatic duct. Three wheat starch and fish meal-based diets were formulated to contain either 15 g fish oil, rapeseed oil or coconut oil/100 g. In both experiments, the diets were fed according to a 3 times 3 Latin square design. The volume of pancreatic juice secreted, pH and secretion of bicarbonate, protein, amylase, trypsin, lipase and colipase were not significantly affected by the diets in the first experiment. In the second experiment, chymotrypsin secretion was significantly greater in pigs fed the coconut oil diet, and secretion of carboxyl ester hydrolase was significantly higher in pigs fed the fish oil diet. When compared qualitatively, pigs in Experiment 2 secreted more pancreatic juice; the pancreatic juice had a higher pH, and trypsin, carboxyl ester hydrolase and colipase secretions were substantially higher whereas amylase secretion was lower than for pigs in Experiment 1. The fatty acid composition of the different oils had minor effects on exocrine pancreatic secretion in growing pigs. However, there were considerable differences between the two surgical methods used to collect pancreatic juice, and these differences may be explained by physiological changes induced by the two methods.