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Abstract: This study determined impacts of a commercial blend of microencapsulated essential oils (EO), fed at increasing dose levels to high yielding primiparous dairy cows, on milk yield and composition. Eight pregnant Holstein heifers, selected to have their parturition within a period of 30d, were kept in tie stalls equipped for individual feeding, and with free access to water, from the 7th month of gestation. At an average of 40d postpartum, cows were assigned to one of four dietary EO levels in a replicated 4×4 Latin square design. The experimental diets (i.e., corn silage, fescue hay and a compound feed, 6.5, 4.4 and 8.7kg DM/d respectively) differed only in the addition level of a microencapsulated EO supplement (RumaXol Feed) mixed at different levels into the compound feed (fed at 1kg/cow day) in order to provide 0, 0.32, 0.64 and 0.96g/d of the EO mixture. The experiment had four experimental periods of 21d, with the last 5d used for collection of faeces and urine, for milk yield and composition recording and measurement of cow biometric data. The dietary EO supplementation had no effect on dry matter (DM) intake, water consumptions or faecal DM, while urine density was (P=0.01) lower at the intermediate EO dosages. Digestibility and biometric measures of cows were not modified by EO feeding. The protein content of milk tended (P=0.06) to be higher at the intermediate EO dosages, as did (P=0.05) the milk energy concentration. However milk and milk component yields were not affected by EO feeding level. [Copyright &y& Elsevier]

Abstract: The aim of this study was to investigate changes over time in chemical composition, digestibility and net energy for lactation (NEl) contents of 12 species of alpine pastures during the vegetative season (i.e., Agrostis tenuis, Anthoxanthum alpinum, Carex sempervirens, Festuca rubra, Nardus stricta, Phleum alpinum, Poa alpina, Poa violacea, Alchemilla vulgaris, Leontodon hispidus, Potentilla aurea, Trifolium repens). Wild seeds were collected from plants spontaneously occurring in mountain pastures in North-East Italy and sown in a greenhouse. Plants were transplanted in open main field plots. Each main plot was divided into sub-plots, which were cut (first cut) in succession every 10 days in two consecutive years. Herbage regrowth (second cut) was evaluated at 45, 60 and 75 days after first cut. Herbage samples were analysed for chemical composition, for in vitro organic matter digestibility (OMD), and the NEl content was estimated. During the pasture utilisation period (i.e., thermic sum between 500 and 1200°C) the species had limited variation in their average CP contents (81–109g/kgDM) excluding the lowest values of F. rubra and P. violacea (74 and 71g/kgDM, respectively; P<0.05) and the highest value of T. repens (202g/kg DM; P<0.05). Within grasses, there were very fibrous species (>700gNDF/kgDM, such as F. rubra, N. stricta and P. violacea) and species with medium contents (573–664gNDF/kgDM), while forbs and the legume specie had a low content (≤403gNDF/kgDM). The OMD ranged from P. violacea (256g/kgDM; P<0.05) to T. repens (730g/kgDM; P<0.05). The highest NEl content was for T. repens (6.3MJ/kgDM; P<0.05), while low NEl values were calculated for N. stricta and C. sempervirens (2.9 and 2.5MJ/kgDM, respectively). The lowest (P<0.05) NEl content was estimated for P. violacea (1.9MJ/kgDM). Most species investigated (in particular, Agrostis tenuis, F. rubra, L. hispidus, Potentilla aurea), had an initial intense decrease in the CP content with advancing season, reaching minimum levels at the thermic sum of 800–1000°C. During season advancement, all species had increased NDF content, with marked increments for F. rubra and Poa species, and all species had decreased NEl contents. Regrowth samples collected at 75 days after first cut had lower CP and NEl contents relative to those collected after 45 days from the first cut (140g/kg versus 160g/kgDM and 4.4MJ/kg versus 4.8MJ/kgDM, respectively; P<0.05). This study provides nutritional information on individual herbage species of alpine pastures at different vegetative phases which can be used to obtain average nutritional values of use in pasture management work. [Copyright &y& Elsevier]

Abstract: The aim of this study was to investigate changes over time in chemical composition, digestibility and net energy for lactation (NEl) contents of 12 species of alpine pastures during the vegetative season (i.e., Agrostis tenuis, Anthoxanthum alpinum, Carex sempervirens, Festuca rubra, Nardus stricta, Phleum alpinum, Poa alpina, Poa violacea, Alchemilla vulgaris, Leontodon hispidus, Potentilla aurea, Trifolium repens). Wild seeds were collected from plants spontaneously occurring in mountain pastures in North-East Italy and sown in a greenhouse. Plants were transplanted in open main field plots. Each main plot was divided into sub-plots, which were cut (first cut) in succession every 10 days in two consecutive years. Herbage regrowth (second cut) was evaluated at 45, 60 and 75 days after first cut. Herbage samples were analysed for chemical composition, for in vitro organic matter digestibility (OMD), and the NEl content was estimated. During the pasture utilisation period (i.e., thermic sum between 500 and 1200°C) the species had limited variation in their average CP contents (81–109g/kgDM) excluding the lowest values of F. rubra and P. violacea (74 and 71g/kgDM, respectively; P<0.05) and the highest value of T. repens (202g/kg DM; P<0.05). Within grasses, there were very fibrous species (>700gNDF/kgDM, such as F. rubra, N. stricta and P. violacea) and species with medium contents (573–664gNDF/kgDM), while forbs and the legume specie had a low content (≤403gNDF/kgDM). The OMD ranged from P. violacea (256g/kgDM; P<0.05) to T. repens (730g/kgDM; P<0.05). The highest NEl content was for T. repens (6.3MJ/kgDM; P<0.05), while low NEl values were calculated for N. stricta and C. sempervirens (2.9 and 2.5MJ/kgDM, respectively). The lowest (P<0.05) NEl content was estimated for P. violacea (1.9MJ/kgDM). Most species investigated (in particular, Agrostis tenuis, F. rubra, L. hispidus, Potentilla aurea), had an initial intense decrease in the CP content with advancing season, reaching minimum levels at the thermic sum of 800–1000°C. During season advancement, all species had increased NDF content, with marked increments for F. rubra and Poa species, and all species had decreased NEl contents. Regrowth samples collected at 75 days after first cut had lower CP and NEl contents relative to those collected after 45 days from the first cut (140g/kg versus 160g/kgDM and 4.4MJ/kg versus 4.8MJ/kgDM, respectively; P<0.05). This study provides nutritional information on individual herbage species of alpine pastures at different vegetative phases which can be used to obtain average nutritional values of use in pasture management work. [Copyright &y& Elsevier]