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Jean-louis Peyraud - One of the best experts on this subject based on the ideXlab platform.
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Does pre-grazing Herbage mass really affect Herbage intake and milk production of strip-grazing dairy cows ?
Grass and Forage Science, 2013Co-Authors: Lucio Alberto Perez Prieto, Jean-louis Peyraud, Remy DelagardeAbstract:The effect of pre-grazing Herbage mass (HM) on Herbage intake and milk production of strip-grazing dairy cows is usually studied at the same Herbage allowance (HA). In the literature, the effect of HM seems to be affected by the cutting height above which HA is estimated. The aim of this 2x3 factorial study was to determine whether the effect of HM (low vs high HM) on Herbage intake, milk production and grazing behaviour of dairy cows is affected by the HA estimation height (ground level vs 2 center dot 5 vs 5cm). Two HMs were compared in three different ways: at same HA above ground level (SHA0), at same HA above 2 center dot 5cm (SHA2) and at same HA above 5cm (SHA5). During two consecutive years, twenty-four Holstein-Friesian dairy cows in mid-lactation were assigned to one estimation height in an incomplete switchback design, with two 14-d periods. There was an interaction between HM and estimation height for Herbage intake and milk production. The effect of HM on Herbage intake was positive, null and negative when HMs were compared at SHA0, SHA2 and SHA5, respectively. This study may have practical implications on future research for studying, directly or indirectly, the effect of pre-grazing HM under strip- or rotational-grazing management, and on modelling Herbage intake at grazing.
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Does pre-grazing Herbage mass really affect Herbage intake and milk production of strip-grazing dairy cows?
Grass and Forage Science, 2012Co-Authors: Lucio Alberto Perez Prieto, Jean-louis Peyraud, R. DelagardeAbstract:The effect of pre-grazing Herbage mass (HM) on Herbage intake and milk production of strip-grazing dairy cows is usually studied at the same Herbage allowance (HA). In the literature, the effect of HM seems to be affected by the cutting height above which HA is estimated. The aim of this 2 · 3 factorial study was to determine whether the effect of HM (low vs high HM) on Herbage intake, milk production and grazing behaviour of dairy cows is affected by the HA estimation height (ground level vs 2AE5 vs 5 cm). Two HMs were compared in three different ways: at same HA above ground level (SHA0), at same HA above 2AE5 cm (SHA2) and at same HA above 5 cm (SHA5). During two consecutive years, twentyfour Holstein-Friesian dairy cows in mid-lactation were assigned to one estimation height in an incomplete switchback design, with two 14-d periods. There was an interaction between HM and estimation height for Herbage intake and milk production. The effect of HM on Herbage intake was positive, null and negative when HMs were compared at SHA0, SHA2 and SHA5, respectively. This study may have practical implications on future research for studying, directly or indirectly, the effect of pre-grazing HM under strip- or rotationalgrazing management, and on modelling Herbage intake at grazing.
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N-alkanes v. ytterbium/faecal index as two methods for estimating Herbage intake of dairy cows fed on diets differing in the Herbage: maize silage ratio and feeding level
animal, 2012Co-Authors: Efrain Perez Ramirez, Jean-louis Peyraud, Remy DelagardeAbstract:The aim of this study was to compare the n-alkanes and the ytterbium (Yb)/faecal index techniques as two methods for estimating the Herbage intake of dairy cows fed indoors on different Herbage : supplement ratios and feeding levels. The supplement was a mixture of maize silage and soyabean meal (ratio of 87 : 13 on a dry matter (DM) basis). In all, four treatments were studied. The Herbage : supplement ratio in the diet was 25 : 75, 50 : 50, 75 : 25 and 50 : 50 for treatments 1, 2, 3 and 4, respectively. Animals were offered for treatments 1, 2 and 3, 100% of ad libitum intake measured before the experiment and 70% of ad libitum intake for treatment 4. Cows were fed Herbage in the morning and supplement in the evening. A total of six lactating Holstein dairy cows were used in a 4 × 4 Latin square with four 14-day periods. Herbage and supplement intakes, faecal output (FO), in vivo organic matter (OM) digestibility and faecal recovery of markers were measured on the last 5 days of each period. Intake was estimated with the two methods and from two faecal sampling techniques, that is, total faecal collection v. grab sampling during milking. Mean Herbage intake as fed, or estimated from n-alkanes or from the Yb/faecal index was 7.7, 8.1 and 10.2 kg DM, respectively. The mean prediction error, expressed as a fraction of actual Herbage intake, was 0.10 and 0.50 for the n-alkanes and Yb/faecal index methods, respectively. The n-alkanes method clearly showed much better accuracy than the Yb/faecal index method for estimating intake, irrespective of the faecal sampling method, Herbage : silage proportion or feeding level. For the n-alkanes method, Herbage intake was slightly overestimated (7%) when Herbage proportion in the diet was high, due to a ratio of faecal C33 : C32 recovery >1. The high bias for the Yb/faecal index was due to the cumulative effect of overestimation of FO (mean recovery of Yb = 0.92) and underestimation of the diet indigestible fraction (-8%). Between-treatment variations of FO were on average well estimated by Yb. Between-treatment variations of OM digestibility estimated using the faecal index technique were lower than those observed in vivo. It is concluded that intake of grazing dairy cows receiving high levels of maize silage supplement should be estimated using the n-alkanes method.
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GrazeIn: a model of Herbage intake and milk production for grazing dairy cows. 3. Simulations and external validation of the model
Grass and Forage Science, 2011Co-Authors: Remy Delagarde, C.s. Mayne, H Valk, A J Rook, C Baratte, Philippe Faverdin, A. González-rodríguez, Jean-louis PeyraudAbstract:GrazeIn is a model for predicting Herbage intake and milk production of grazing dairy cows. The objectives of this paper are to test its robustness according to a planned arrangement of grazing and feeding scenarios using a simulation procedure, and to investigate the precision of the predictions from an external validation procedure with independent data. Simulations show that the predicted effects of Herbage allowance, Herbage mass, Herbage digestibility, concentrate supplementation, forage supplementation and daily time at pasture are consistent with current knowledge. The external validation of GrazeIn is investigated from a large dataset of twenty experiments representing 206 grazing herds, from five research centres within Western Europe. On average, mean actual and predicted values are 14 center dot 4 and 14 center dot 2 kg DM d-1 for Herbage intake and 22 center dot 7 and 24 center dot 7 kg d-1 for milk production, respectively. The overall precision of the predictions, estimated by the mean prediction error, are 16% (i.e. 2 center dot 3 kg DM d-1) and 14% (i.e. 3 center dot 1 kg d-1) for Herbage intake and milk production, respectively. It is concluded that the GrazeIn model is able to predict variations in Herbage intake and milk production of grazing dairy cows in a realistic manner over a wide range of grazing management practices, rendering it suitable as a basis for decision support systems.
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Herbage intake and milk yield of dairy cows grazing perennial ryegrass swards or white clover perennial ryegrass swards at low and medium Herbage allowances
Animal Feed Science and Technology, 2005Co-Authors: H Ribeiro M N Filho, Remy Delagarde, Jean-louis PeyraudAbstract:Abstract Including legumes in grass swards generally increases nutrient intake and performance of grazing cattle. The objective of this study was to determine if the difference in Herbage intake of dairy cows grazing either perennial ryegrass swards (PRG) or white clover/perennial ryegrass swards (GC) is a function of Herbage allowance. Both sward types were compared at 20 or 35 kg DM/cow/day offered at ground level according to a 4 × 4 Latin square design with four 10-day periods and with 24 Holstein cows in mid-lactation. Clover represented on average 270 g/kg of live DM material in GC swards. Pre-grazing Herbage mass at ground level did not differ between sward types but pre-grazing Herbage mass above 5 cm and sward height was much lower on GC than on PRG swards. There was no interaction between sward type and Herbage allowance on Herbage intake and milk yield. Cows grazing on GC swards had lower Herbage intake (−0.7 kg OM/day), OM digestibility of the selected Herbage (−20 g/kg OM) and milk yield (−1.3 kg/day) than cows grazing on PRG swards. Milk fat content was unaffected by sward type and milk protein content was lower on GC than on PRG swards. Herbage intake, Herbage OM digestibility, milk yield and milk protein content increased, and milk fat content decreased, with increasing Herbage allowance. It is concluded that including white clover in perennial ryegrass swards, along with suppressing nitrogen fertilisation, did not improve Herbage intake or milk production when this is associated with a sharp decrease in sward height and Herbage mass in the upper strata of the sward.
Remy Delagarde - One of the best experts on this subject based on the ideXlab platform.
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Prediction of in vivo digestibility of pasture-based diets in dairy goats from faecal indicators
2017Co-Authors: Alexia Charpentier, Solveig Mendowski, Remy DelagardeAbstract:For estimating quality and intake of pasture Herbage by grazing goats, estimation of Herbage digestibility is often required. The aim of this work was to predict in vivo organic matter digestibility (OMD) of diets based on temperate pasture forage from faecal composition (CP mainly). A series of indoor experiments was carried out with goats fed on grass hay or with fresh Herbage cut daily and given either ad libitum or in restricted amounts, to mimic the effect of pasture Herbage availability. Concentrate supplementation level and regrowth age of the Herbage were also studied in order to achieve a wide range of diets composition and quality. Intake of each feed, and of faecal output (total collection), were measured precisely during 5 consecutive days in each experimental period. For each dataset (fresh pasture Herbage only or fresh pasture Herbage + hay), there was a strong and inverse relationship between OMD and faecal crude protein (CP) concentration. Including dietary CP concentration in the regression allowed increased accuracy of the prediction. The proposed equations, relevant for good quality pastures, show a good continuum with previous published equations on goats fed on much less digestible tropical, Mediterranean or Sahelian forages.
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Does pre-grazing Herbage mass really affect Herbage intake and milk production of strip-grazing dairy cows ?
Grass and Forage Science, 2013Co-Authors: Lucio Alberto Perez Prieto, Jean-louis Peyraud, Remy DelagardeAbstract:The effect of pre-grazing Herbage mass (HM) on Herbage intake and milk production of strip-grazing dairy cows is usually studied at the same Herbage allowance (HA). In the literature, the effect of HM seems to be affected by the cutting height above which HA is estimated. The aim of this 2x3 factorial study was to determine whether the effect of HM (low vs high HM) on Herbage intake, milk production and grazing behaviour of dairy cows is affected by the HA estimation height (ground level vs 2 center dot 5 vs 5cm). Two HMs were compared in three different ways: at same HA above ground level (SHA0), at same HA above 2 center dot 5cm (SHA2) and at same HA above 5cm (SHA5). During two consecutive years, twenty-four Holstein-Friesian dairy cows in mid-lactation were assigned to one estimation height in an incomplete switchback design, with two 14-d periods. There was an interaction between HM and estimation height for Herbage intake and milk production. The effect of HM on Herbage intake was positive, null and negative when HMs were compared at SHA0, SHA2 and SHA5, respectively. This study may have practical implications on future research for studying, directly or indirectly, the effect of pre-grazing HM under strip- or rotational-grazing management, and on modelling Herbage intake at grazing.
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N-alkanes v. ytterbium/faecal index as two methods for estimating Herbage intake of dairy cows fed on diets differing in the Herbage: maize silage ratio and feeding level
animal, 2012Co-Authors: Efrain Perez Ramirez, Jean-louis Peyraud, Remy DelagardeAbstract:The aim of this study was to compare the n-alkanes and the ytterbium (Yb)/faecal index techniques as two methods for estimating the Herbage intake of dairy cows fed indoors on different Herbage : supplement ratios and feeding levels. The supplement was a mixture of maize silage and soyabean meal (ratio of 87 : 13 on a dry matter (DM) basis). In all, four treatments were studied. The Herbage : supplement ratio in the diet was 25 : 75, 50 : 50, 75 : 25 and 50 : 50 for treatments 1, 2, 3 and 4, respectively. Animals were offered for treatments 1, 2 and 3, 100% of ad libitum intake measured before the experiment and 70% of ad libitum intake for treatment 4. Cows were fed Herbage in the morning and supplement in the evening. A total of six lactating Holstein dairy cows were used in a 4 × 4 Latin square with four 14-day periods. Herbage and supplement intakes, faecal output (FO), in vivo organic matter (OM) digestibility and faecal recovery of markers were measured on the last 5 days of each period. Intake was estimated with the two methods and from two faecal sampling techniques, that is, total faecal collection v. grab sampling during milking. Mean Herbage intake as fed, or estimated from n-alkanes or from the Yb/faecal index was 7.7, 8.1 and 10.2 kg DM, respectively. The mean prediction error, expressed as a fraction of actual Herbage intake, was 0.10 and 0.50 for the n-alkanes and Yb/faecal index methods, respectively. The n-alkanes method clearly showed much better accuracy than the Yb/faecal index method for estimating intake, irrespective of the faecal sampling method, Herbage : silage proportion or feeding level. For the n-alkanes method, Herbage intake was slightly overestimated (7%) when Herbage proportion in the diet was high, due to a ratio of faecal C33 : C32 recovery >1. The high bias for the Yb/faecal index was due to the cumulative effect of overestimation of FO (mean recovery of Yb = 0.92) and underestimation of the diet indigestible fraction (-8%). Between-treatment variations of FO were on average well estimated by Yb. Between-treatment variations of OM digestibility estimated using the faecal index technique were lower than those observed in vivo. It is concluded that intake of grazing dairy cows receiving high levels of maize silage supplement should be estimated using the n-alkanes method.
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GrazeIn: a model of Herbage intake and milk production for grazing dairy cows. 3. Simulations and external validation of the model
Grass and Forage Science, 2011Co-Authors: Remy Delagarde, C.s. Mayne, H Valk, A J Rook, C Baratte, Philippe Faverdin, A. González-rodríguez, Jean-louis PeyraudAbstract:GrazeIn is a model for predicting Herbage intake and milk production of grazing dairy cows. The objectives of this paper are to test its robustness according to a planned arrangement of grazing and feeding scenarios using a simulation procedure, and to investigate the precision of the predictions from an external validation procedure with independent data. Simulations show that the predicted effects of Herbage allowance, Herbage mass, Herbage digestibility, concentrate supplementation, forage supplementation and daily time at pasture are consistent with current knowledge. The external validation of GrazeIn is investigated from a large dataset of twenty experiments representing 206 grazing herds, from five research centres within Western Europe. On average, mean actual and predicted values are 14 center dot 4 and 14 center dot 2 kg DM d-1 for Herbage intake and 22 center dot 7 and 24 center dot 7 kg d-1 for milk production, respectively. The overall precision of the predictions, estimated by the mean prediction error, are 16% (i.e. 2 center dot 3 kg DM d-1) and 14% (i.e. 3 center dot 1 kg d-1) for Herbage intake and milk production, respectively. It is concluded that the GrazeIn model is able to predict variations in Herbage intake and milk production of grazing dairy cows in a realistic manner over a wide range of grazing management practices, rendering it suitable as a basis for decision support systems.
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Herbage intake and milk yield of dairy cows grazing perennial ryegrass swards or white clover perennial ryegrass swards at low and medium Herbage allowances
Animal Feed Science and Technology, 2005Co-Authors: H Ribeiro M N Filho, Remy Delagarde, Jean-louis PeyraudAbstract:Abstract Including legumes in grass swards generally increases nutrient intake and performance of grazing cattle. The objective of this study was to determine if the difference in Herbage intake of dairy cows grazing either perennial ryegrass swards (PRG) or white clover/perennial ryegrass swards (GC) is a function of Herbage allowance. Both sward types were compared at 20 or 35 kg DM/cow/day offered at ground level according to a 4 × 4 Latin square design with four 10-day periods and with 24 Holstein cows in mid-lactation. Clover represented on average 270 g/kg of live DM material in GC swards. Pre-grazing Herbage mass at ground level did not differ between sward types but pre-grazing Herbage mass above 5 cm and sward height was much lower on GC than on PRG swards. There was no interaction between sward type and Herbage allowance on Herbage intake and milk yield. Cows grazing on GC swards had lower Herbage intake (−0.7 kg OM/day), OM digestibility of the selected Herbage (−20 g/kg OM) and milk yield (−1.3 kg/day) than cows grazing on PRG swards. Milk fat content was unaffected by sward type and milk protein content was lower on GC than on PRG swards. Herbage intake, Herbage OM digestibility, milk yield and milk protein content increased, and milk fat content decreased, with increasing Herbage allowance. It is concluded that including white clover in perennial ryegrass swards, along with suppressing nitrogen fertilisation, did not improve Herbage intake or milk production when this is associated with a sharp decrease in sward height and Herbage mass in the upper strata of the sward.
Donagh P. Berry - One of the best experts on this subject based on the ideXlab platform.
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Weather, Herbage quality and milk production in pastoral systems. 3. Inter-relationships and associations between weather variables and Herbage growth rate, quality and mineral concentration
Animal Production Science, 2009Co-Authors: John R. Roche, Lr Turner, Julia M. Lee, D. C. Edmeades, Dj Donaghy, K.a. Macdonald, J.w. Penno, Donagh P. BerryAbstract:Prevailing weather conditions influence Herbage growth and quality, and therefore may have a substantial impact on animal production. Before investigating relationships between weather factors, Herbage quality and animal production, it is beneficial to first quantify interactions between Herbage quality characteristics and mineral concentrations. The objective of the present study was to investigate the association between weather and Herbage growth rate, quality and mineral concentration under rotational grazing systems. Daily weather data and weekly records of Herbage quality and mineral concentration from a research dairy farm were available across the years 1995 to 2001, inclusive. Herbage growth rates were also recorded on a monthly basis. Results imply moderate correlations between some weather variables and Herbage quality and mineral concentration. Generally, the strength of the absolute correlations between weather and Herbage-related variables decreased following adjustment of the Herbage-related variables for month of year and research farmlet. Negative correlations existed between rainfall and Herbage water-soluble carbohydrate (r = –0.19) and organic matter digestibility concentration (r = –0.13) and metabolisable energy content (r = –0.14), independent of time of year and farmlet. Weather explained up to 14% of the variation in Herbage nutrient content over and above that explained by time of year and farmlet. Significantly different correlations existed across time between some weather and Herbage-related variables, indicating that the relationships may differ across seasons. Results from the present study, in conjunction with information on the effect of Herbage quality and/or mineral concentration on animal production, will be valuable in improving our understanding of weather influences on Herbage growth, quality and mineral concentration.
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Weather, Herbage quality and milk production in pastoral systems. 2. Temporal patterns and intra-relationships in Herbage quality and mineral concentration parameters
Animal Production Science, 2009Co-Authors: John R. Roche, Lr Turner, Julia M. Lee, D. C. Edmeades, Dj Donaghy, K.a. Macdonald, J.w. Penno, Donagh P. BerryAbstract:Prevailing weather conditions influence Herbage growth and quality, and therefore may have a substantial impact on animal production. Before investigating relationships between weather factors, Herbage quality, and animal production, it is beneficial to first quantify temporal trends in Herbage quality characteristics and mineral concentrations. The objective of the present study was to investigate the existence of temporal trends in Herbage quality characteristics and mineral concentrations, and to quantify the intra-dependency among these variables. Weekly Herbage quality and mineral concentration data from a research farm were collected from 1995 to 2001, inclusive. Fitted sinusoidal functions demonstrated cyclic temporal trends across Herbage quality variables, but there was little cyclic temporal variation in the majority of Herbage mineral concentration variables. The repeatability of Herbage quality measurements was low to moderate (22% for ether extract to 54% for metabolisable energy). Linear relationships were observed within all Herbage quality variables and Herbage mineral concentration variables. Neutral detergent fibre and acid detergent fibre concentrations were strongly positively correlated with each other (r = 0.87), and negatively correlated with Herbage digestibility (r = –0.64 and –0.74, respectively), water-soluble carbohydrate concentration (r = –0.52 and –0.68, respectively) and metabolisable energy content (r = –0.60 and –0.75, respectively). The absolute correlations among most Herbage minerals were poor (r <0.30). However, magnesium concentration was positively correlated with calcium (r = 0.54), copper (r = 0.56), and manganese (r = 0.37) concentrations, and negatively correlated with zinc (r = –0.56) concentration. Further investigation is required into the relationships between temporal weather and Herbage quality trends, and their impact on animal production.
R. Delagarde - One of the best experts on this subject based on the ideXlab platform.
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Does pre-grazing Herbage mass really affect Herbage intake and milk production of strip-grazing dairy cows?
Grass and Forage Science, 2012Co-Authors: Lucio Alberto Perez Prieto, Jean-louis Peyraud, R. DelagardeAbstract:The effect of pre-grazing Herbage mass (HM) on Herbage intake and milk production of strip-grazing dairy cows is usually studied at the same Herbage allowance (HA). In the literature, the effect of HM seems to be affected by the cutting height above which HA is estimated. The aim of this 2 · 3 factorial study was to determine whether the effect of HM (low vs high HM) on Herbage intake, milk production and grazing behaviour of dairy cows is affected by the HA estimation height (ground level vs 2AE5 vs 5 cm). Two HMs were compared in three different ways: at same HA above ground level (SHA0), at same HA above 2AE5 cm (SHA2) and at same HA above 5 cm (SHA5). During two consecutive years, twentyfour Holstein-Friesian dairy cows in mid-lactation were assigned to one estimation height in an incomplete switchback design, with two 14-d periods. There was an interaction between HM and estimation height for Herbage intake and milk production. The effect of HM on Herbage intake was positive, null and negative when HMs were compared at SHA0, SHA2 and SHA5, respectively. This study may have practical implications on future research for studying, directly or indirectly, the effect of pre-grazing HM under strip- or rotationalgrazing management, and on modelling Herbage intake at grazing.
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n alkanes v ytterbium faecal index as two methods for estimating Herbage intake of dairy cows fed on diets differing in the Herbage maize silage ratio and feeding level
Animal, 2012Co-Authors: E Perezramirez, J L Peyraud, R. DelagardeAbstract:The aim of this study was to compare the n-alkanes and the ytterbium (Yb)/faecal index techniques as two methods for estimating the Herbage intake of dairy cows fed indoors on different Herbage : supplement ratios and feeding levels. The supplement was a mixture of maize silage and soyabean meal (ratio of 87 : 13 on a dry matter (DM) basis). In all, four treatments were studied. The Herbage : supplement ratio in the diet was 25 : 75, 50 : 50, 75 : 25 and 50 : 50 for treatments 1, 2, 3 and 4, respectively. Animals were offered for treatments 1, 2 and 3, 100% of ad libitum intake measured before the experiment and 70% of ad libitum intake for treatment 4. Cows were fed Herbage in the morning and supplement in the evening. A total of six lactating Holstein dairy cows were used in a 4 3 4 Latin square with four 14-day periods. Herbage and supplement intakes, faecal output (FO), in vivo organic matter (OM) digestibility and faecal recovery of markers were measured on the last 5 days of each period. Intake was estimated with the two methods and from two faecal sampling techniques, that is, total faecal collection v. grab sampling during milking. Mean Herbage intake as fed, or estimated from n-alkanes or from the Yb/faecal index was 7.7, 8.1 and 10.2 kg DM, respectively. The mean prediction error, expressed as a fraction of actual Herbage intake, was 0.10 and 0.50 for the n-alkanes and Yb/faecal index methods, respectively. The n-alkanes method clearly showed much better accuracy than the Yb/faecal index method for estimating intake, irrespective of the faecal sampling method, Herbage : silage proportion or feeding level. For the nalkanes method, Herbage intake was slightly overestimated (7%) when Herbage proportion in the diet was high, due to a ratio of faecal C33 :C 32 recovery .1. The high bias for the Yb/faecal index was due to the cumulative effect of overestimation of FO (mean recovery of Yb 5 0.92) and underestimation of the diet indigestible fraction (28%). Between-treatment variations of FO were on average well estimated by Yb. Between-treatment variations of OM digestibility estimated using the faecal index technique were lower than those observed in vivo. It is concluded that intake of grazing dairy cows receiving high levels of maize silage supplement should be estimated using the n-alkanes method.
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grazein a model of Herbage intake and milk production for grazing dairy cows 3 simulations and external validation of the model
Grass and Forage Science, 2011Co-Authors: R. Delagarde, C.s. Mayne, H Valk, A J Rook, A Gonzalezrodriguez, C Baratte, Philippe Faverdin, J L PeyraudAbstract:GrazeIn is a model for predicting Herbage intake and milk production of grazing dairy cows. The objectives of this paper are to test its robustness according to a planned arrangement of grazing and feeding scenarios using a simulation procedure, and to investigate the precision of the predictions from an external validation procedure with independent data. Simulations show that the predicted effects of Herbage allowance, Herbage mass, Herbage digestibility, concentrate supplementation, forage supplementation and daily time at pasture are consistent with current knowledge. The external validation of GrazeIn is investigated from a large dataset of twenty experiments representing 206 grazing herds, from five research centres within Western Europe. On average, mean actual and predicted values are 14·4 and 14·2 kg DM d−1 for Herbage intake and 22·7 and 24·7 kg d−1 for milk production, respectively. The overall precision of the predictions, estimated by the mean prediction error, are 16% (i.e. 2·3 kg DM d−1) and 14% (i.e. 3·1 kg d−1) for Herbage intake and milk production, respectively. It is concluded that the GrazeIn model is able to predict variations in Herbage intake and milk production of grazing dairy cows in a realistic manner over a wide range of grazing management practices, rendering it suitable as a basis for decision support systems.
John R. Roche - One of the best experts on this subject based on the ideXlab platform.
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Weather, Herbage quality and milk production in pastoral systems. 3. Inter-relationships and associations between weather variables and Herbage growth rate, quality and mineral concentration
Animal Production Science, 2009Co-Authors: John R. Roche, Lr Turner, Julia M. Lee, D. C. Edmeades, Dj Donaghy, K.a. Macdonald, J.w. Penno, Donagh P. BerryAbstract:Prevailing weather conditions influence Herbage growth and quality, and therefore may have a substantial impact on animal production. Before investigating relationships between weather factors, Herbage quality and animal production, it is beneficial to first quantify interactions between Herbage quality characteristics and mineral concentrations. The objective of the present study was to investigate the association between weather and Herbage growth rate, quality and mineral concentration under rotational grazing systems. Daily weather data and weekly records of Herbage quality and mineral concentration from a research dairy farm were available across the years 1995 to 2001, inclusive. Herbage growth rates were also recorded on a monthly basis. Results imply moderate correlations between some weather variables and Herbage quality and mineral concentration. Generally, the strength of the absolute correlations between weather and Herbage-related variables decreased following adjustment of the Herbage-related variables for month of year and research farmlet. Negative correlations existed between rainfall and Herbage water-soluble carbohydrate (r = –0.19) and organic matter digestibility concentration (r = –0.13) and metabolisable energy content (r = –0.14), independent of time of year and farmlet. Weather explained up to 14% of the variation in Herbage nutrient content over and above that explained by time of year and farmlet. Significantly different correlations existed across time between some weather and Herbage-related variables, indicating that the relationships may differ across seasons. Results from the present study, in conjunction with information on the effect of Herbage quality and/or mineral concentration on animal production, will be valuable in improving our understanding of weather influences on Herbage growth, quality and mineral concentration.
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Weather, Herbage quality and milk production in pastoral systems. 2. Temporal patterns and intra-relationships in Herbage quality and mineral concentration parameters
Animal Production Science, 2009Co-Authors: John R. Roche, Lr Turner, Julia M. Lee, D. C. Edmeades, Dj Donaghy, K.a. Macdonald, J.w. Penno, Donagh P. BerryAbstract:Prevailing weather conditions influence Herbage growth and quality, and therefore may have a substantial impact on animal production. Before investigating relationships between weather factors, Herbage quality, and animal production, it is beneficial to first quantify temporal trends in Herbage quality characteristics and mineral concentrations. The objective of the present study was to investigate the existence of temporal trends in Herbage quality characteristics and mineral concentrations, and to quantify the intra-dependency among these variables. Weekly Herbage quality and mineral concentration data from a research farm were collected from 1995 to 2001, inclusive. Fitted sinusoidal functions demonstrated cyclic temporal trends across Herbage quality variables, but there was little cyclic temporal variation in the majority of Herbage mineral concentration variables. The repeatability of Herbage quality measurements was low to moderate (22% for ether extract to 54% for metabolisable energy). Linear relationships were observed within all Herbage quality variables and Herbage mineral concentration variables. Neutral detergent fibre and acid detergent fibre concentrations were strongly positively correlated with each other (r = 0.87), and negatively correlated with Herbage digestibility (r = –0.64 and –0.74, respectively), water-soluble carbohydrate concentration (r = –0.52 and –0.68, respectively) and metabolisable energy content (r = –0.60 and –0.75, respectively). The absolute correlations among most Herbage minerals were poor (r <0.30). However, magnesium concentration was positively correlated with calcium (r = 0.54), copper (r = 0.56), and manganese (r = 0.37) concentrations, and negatively correlated with zinc (r = –0.56) concentration. Further investigation is required into the relationships between temporal weather and Herbage quality trends, and their impact on animal production.