On-farm evaluation of models to predict herbage intake of dairy cows grazing temperate semi-natural grasslands
The objective of the present on-farm study was to evaluate the adequacy of existing models in predicting the pasture herbage DM intake (PDMI) of lactating dairy cows grazing semi-natural grasslands. The prediction adequacy of 13 empirical and semi-mechanistic models, which were predominantly develop...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2023-05-01
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| Series: | Animal |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S1751731123001027 |
| _version_ | 1797824483259580416 |
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| author | S. Perdana-Decker E. Velasco J. Werner U. Dickhoefer |
| author_facet | S. Perdana-Decker E. Velasco J. Werner U. Dickhoefer |
| author_sort | S. Perdana-Decker |
| collection | DOAJ |
| description | The objective of the present on-farm study was to evaluate the adequacy of existing models in predicting the pasture herbage DM intake (PDMI) of lactating dairy cows grazing semi-natural grasslands. The prediction adequacy of 13 empirical and semi-mechanistic models, which were predominantly developed to represent stall-fed cows or cows grazing high-quality pastures, were evaluated using the mean bias, relative prediction error (RPE), and partitioning of mean square error of prediction, where models with an RPE ≤ 20% were considered adequate. The reference dataset comprised n = 233 individual animal observations from nine commercial farms in South Germany with a mean milk production, DM intake, and PDMI (arithmetic means ± one SD) of 24 kg/d, (±5.6), 21 kg/d (±3.2), and 12 kg/d (±5.1), respectively. Despite their adaptation to grazing conditions, the behaviour-based and semi-mechanistic grazing-based models had the lowest prediction adequacy among the evaluated models. Their underlying empirical equations likely did not fit the grazing and production conditions of low-input farms using semi-natural grasslands for grazing. The semi-mechanistic stall-based model Mertens II with slight modifications achieved the highest and a satisfactory modelling performance (RPE = 13.4%) when evaluated based on the mean observed PDMI, i.e., averaged across animals per farm and period (n = 28). It also allowed for the adequate prediction of PDMI on individual cows (RPE = 18.5%) that were fed < 4.8 kg DM of supplement feed per day. Nevertheless, when used to predict PDMI of individual animals receiving a high supplementation level, the model Mertens II also did not meet the threshold for an acceptable adequacy (RPE = 24.7%). It was concluded that this lack of prediction adequacy for animals receiving greater levels of supplementation was due to a lack of modelling precision, which mainly could be related to inter-animal and methodological limitations such as the lack of individually measured supplement feed intake for some cows. The latter limitation is a trade-off of the on-farm research approach of the present study, which was chosen to represent the range in feed intake of dairy cows across the diverse low-input farming systems using semi-natural grasslands for grazing. |
| first_indexed | 2024-03-13T10:39:39Z |
| format | Article |
| id | doaj.art-07d51a38ad6b4466b62e7f54c2cc3c7b |
| institution | Directory Open Access Journal |
| issn | 1751-7311 |
| language | English |
| last_indexed | 2024-03-13T10:39:39Z |
| publishDate | 2023-05-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Animal |
| spelling | doaj.art-07d51a38ad6b4466b62e7f54c2cc3c7b2023-05-18T04:39:25ZengElsevierAnimal1751-73112023-05-01175100806On-farm evaluation of models to predict herbage intake of dairy cows grazing temperate semi-natural grasslandsS. Perdana-Decker0E. Velasco1J. Werner2U. Dickhoefer3Department of Animal Nutrition and Rangeland Management in the Tropics and Subtropics, Institute of Agricultural Sciences in the Tropics, University of Hohenheim, Fruwirthstr. 31, 70599 Stuttgart, GermanyDepartment of Animal Nutrition and Rangeland Management in the Tropics and Subtropics, Institute of Agricultural Sciences in the Tropics, University of Hohenheim, Fruwirthstr. 31, 70599 Stuttgart, GermanyDepartment of Animal Nutrition and Rangeland Management in the Tropics and Subtropics, Institute of Agricultural Sciences in the Tropics, University of Hohenheim, Fruwirthstr. 31, 70599 Stuttgart, GermanyDepartment of Animal Nutrition and Rangeland Management in the Tropics and Subtropics, Institute of Agricultural Sciences in the Tropics, University of Hohenheim, Fruwirthstr. 31, 70599 Stuttgart, Germany; Institute of Animal Nutrition and Physiology, Kiel University, Hermann-Rodewald-Str. 9, 24118 Kiel, Germany; Corresponding author at: Institute of Animal Nutrition and Physiology, Kiel University, Hermann-Rodewald-Str. 9, 24118 Kiel, Germany.The objective of the present on-farm study was to evaluate the adequacy of existing models in predicting the pasture herbage DM intake (PDMI) of lactating dairy cows grazing semi-natural grasslands. The prediction adequacy of 13 empirical and semi-mechanistic models, which were predominantly developed to represent stall-fed cows or cows grazing high-quality pastures, were evaluated using the mean bias, relative prediction error (RPE), and partitioning of mean square error of prediction, where models with an RPE ≤ 20% were considered adequate. The reference dataset comprised n = 233 individual animal observations from nine commercial farms in South Germany with a mean milk production, DM intake, and PDMI (arithmetic means ± one SD) of 24 kg/d, (±5.6), 21 kg/d (±3.2), and 12 kg/d (±5.1), respectively. Despite their adaptation to grazing conditions, the behaviour-based and semi-mechanistic grazing-based models had the lowest prediction adequacy among the evaluated models. Their underlying empirical equations likely did not fit the grazing and production conditions of low-input farms using semi-natural grasslands for grazing. The semi-mechanistic stall-based model Mertens II with slight modifications achieved the highest and a satisfactory modelling performance (RPE = 13.4%) when evaluated based on the mean observed PDMI, i.e., averaged across animals per farm and period (n = 28). It also allowed for the adequate prediction of PDMI on individual cows (RPE = 18.5%) that were fed < 4.8 kg DM of supplement feed per day. Nevertheless, when used to predict PDMI of individual animals receiving a high supplementation level, the model Mertens II also did not meet the threshold for an acceptable adequacy (RPE = 24.7%). It was concluded that this lack of prediction adequacy for animals receiving greater levels of supplementation was due to a lack of modelling precision, which mainly could be related to inter-animal and methodological limitations such as the lack of individually measured supplement feed intake for some cows. The latter limitation is a trade-off of the on-farm research approach of the present study, which was chosen to represent the range in feed intake of dairy cows across the diverse low-input farming systems using semi-natural grasslands for grazing.http://www.sciencedirect.com/science/article/pii/S1751731123001027Dairy cattleFeed intakeGrazing behaviourModel evaluationPasture |
| spellingShingle | S. Perdana-Decker E. Velasco J. Werner U. Dickhoefer On-farm evaluation of models to predict herbage intake of dairy cows grazing temperate semi-natural grasslands Animal Dairy cattle Feed intake Grazing behaviour Model evaluation Pasture |
| title | On-farm evaluation of models to predict herbage intake of dairy cows grazing temperate semi-natural grasslands |
| title_full | On-farm evaluation of models to predict herbage intake of dairy cows grazing temperate semi-natural grasslands |
| title_fullStr | On-farm evaluation of models to predict herbage intake of dairy cows grazing temperate semi-natural grasslands |
| title_full_unstemmed | On-farm evaluation of models to predict herbage intake of dairy cows grazing temperate semi-natural grasslands |
| title_short | On-farm evaluation of models to predict herbage intake of dairy cows grazing temperate semi-natural grasslands |
| title_sort | on farm evaluation of models to predict herbage intake of dairy cows grazing temperate semi natural grasslands |
| topic | Dairy cattle Feed intake Grazing behaviour Model evaluation Pasture |
| url | http://www.sciencedirect.com/science/article/pii/S1751731123001027 |
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