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British Poultry Science Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/cbps20
Seasonal variations in the food intake of captive red grouse C. J. Savory
a b
a
Institute of Terrestrial Ecology , Blackhall, Banchory, Kincardineshire, Scotland b
Agricultural Research Council's , Poultry Research Centre , King's Buildings, West Mains Road, Edinburgh, EH9 3JS, Scotland Published online: 08 Nov 2007.
To cite this article: C. J. Savory (1975) Seasonal variations in the food intake of captive red grouse, British Poultry Science, 16:5, 471-479, DOI: 10.1080/00071667508416215 To link to this article: http://dx.doi.org/10.1080/00071667508416215
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://www.tandfonline.com/page/ terms-and-conditions
Br. Poult. Sci., x6: 471-479. 1975
Longman: printed in Great Britain
SEASONAL VARIATIONS INTHE FOOD INTAKE OF CAPTIVE RED GROUSE C. J. SAVORY1 Institute of Terrestrial Ecology, Blackhall, Banchory, Kincardineshire, Scotland
Downloaded by [York University Libraries] at 07:16 01 February 2015
Received for publication 24th September 1974
1. The daily food intake of captive red grouse was measured throughout the year. It was positively related to body weight and to daylength, and negatively to air temperature. Grouse ate more during their main summer moult, and the hens ate most while producing eggs. 2. The total weight of eggs laid was positively related to daily food intake during the 5 weeks before laying, but not to daily intake during laying. The rate at which eggs were laid was related to daily intake during laying as well as before laying. The possible significance of these results for poultry management is discussed. INTRODUCTION
In this paper, variations in the daily food intake of captive red grouse (Lagopus lagopus scoticus [Lath.]) throughout the year are considered in relation to their body weight, moult and egg production, and also to daylength and air temperature. This work was part of a 2-year study of the annual food requirements of red grouse, full details of which are given in an unpublished thesis (Savory, 1974). MATERIALS AND METHODS
The captive grouse used for measuring food intake were adults which had been hatched and reared in captivity. Husbandry conditions have been described by Moss (1969a). The birds were kept separately in outdoor cages measuring 0-90 x 0-75 x o-8o m, with wire-mesh floors. They were fed on a staple diet of grouse " maintenance " pellets (RHM Caledonia, Waterloo Quay, Aberdeen) with grit and water, all provided ad libitum, and in addition each bird was given a small bundle of heather (Calluna vulgaris) two or three times a week. The heather normally constituted about 5 to 10% of the dry weight of their diet. From March until July they were all fed on grouse " breeders " pellets. The fibre content of both types of pellets is higher (12% and 11% respectively) than in standard poultry foods so as to resemble the fibrous nature of the heather diet of wild grouse. The detailed composition of the diets is confidential, but both types contain all known nutrients in excess 1 Present address: Agricultural Research Council's Poultry Research Centre, King's Buildings, West Mains Road, Edinburgh EH9 3JS, Scotland. 16/5—D 471
Downloaded by [York University Libraries] at 07:16 01 February 2015
472
C. J. SAVORY
of comparable poultry requirements (National Research Council, i960; Agricultural Research Council, 1963). Food intake was measured on 1 d each week from June 1969 until August 1971. Generally four to six grouse of each sex were used, and the same individuals from week to week; if any one died it was replaced by a bird of about the same weight. The bundles of heather were removed and each bird was supplied with a known weight of maintenance pellets in a small feeding trough. The troughs, which had lids with holes to prevent spillage, were taken out at the end of 24 h and the remaining food weighed to find the weight eaten. Correction for any weight change due to moisture changes was made by using a control dish of weighed pellets, but at the most the change amounted to only 0-3% of the weight of food. In spring, when all the birds were fed on breeders pellets, food intake was expressed in terms of maintenance pellets for easy comparison with other times of year. When pellets of the different types were fed on consecutive days, the intake of breeders pellets was 92% of the intake of maintenance pellets. On the days when food intake was measured, air temperature and body weight were measured and the state of moult was noted. Seasonal changes in the plumage of adult grouse have been described by Wilson (1911). Old unmoulted primaries, new primaries wholly or partly in sheath and complete new primaries were counted, and also the state of moult was scored from o (no moult) to 5 (maximum, large areas of the body with >75% of feathers in moult). At most times of year, some birds had one or two very small feathers growing on their crowns, but they were considered insignificant and scored zero for body moult. In spring, the number and weight of eggs laid were also recorded. RESULTS
Body weight
The mean weights of hens in different months were significantly correlated (P
British Poultry Science Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/cbps20
Seasonal variations in the food intake of captive red grouse C. J. Savory
a b
a
Institute of Terrestrial Ecology , Blackhall, Banchory, Kincardineshire, Scotland b
Agricultural Research Council's , Poultry Research Centre , King's Buildings, West Mains Road, Edinburgh, EH9 3JS, Scotland Published online: 08 Nov 2007.
To cite this article: C. J. Savory (1975) Seasonal variations in the food intake of captive red grouse, British Poultry Science, 16:5, 471-479, DOI: 10.1080/00071667508416215 To link to this article: http://dx.doi.org/10.1080/00071667508416215
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://www.tandfonline.com/page/ terms-and-conditions
Br. Poult. Sci., x6: 471-479. 1975
Longman: printed in Great Britain
SEASONAL VARIATIONS INTHE FOOD INTAKE OF CAPTIVE RED GROUSE C. J. SAVORY1 Institute of Terrestrial Ecology, Blackhall, Banchory, Kincardineshire, Scotland
Downloaded by [York University Libraries] at 07:16 01 February 2015
Received for publication 24th September 1974
1. The daily food intake of captive red grouse was measured throughout the year. It was positively related to body weight and to daylength, and negatively to air temperature. Grouse ate more during their main summer moult, and the hens ate most while producing eggs. 2. The total weight of eggs laid was positively related to daily food intake during the 5 weeks before laying, but not to daily intake during laying. The rate at which eggs were laid was related to daily intake during laying as well as before laying. The possible significance of these results for poultry management is discussed. INTRODUCTION
In this paper, variations in the daily food intake of captive red grouse (Lagopus lagopus scoticus [Lath.]) throughout the year are considered in relation to their body weight, moult and egg production, and also to daylength and air temperature. This work was part of a 2-year study of the annual food requirements of red grouse, full details of which are given in an unpublished thesis (Savory, 1974). MATERIALS AND METHODS
The captive grouse used for measuring food intake were adults which had been hatched and reared in captivity. Husbandry conditions have been described by Moss (1969a). The birds were kept separately in outdoor cages measuring 0-90 x 0-75 x o-8o m, with wire-mesh floors. They were fed on a staple diet of grouse " maintenance " pellets (RHM Caledonia, Waterloo Quay, Aberdeen) with grit and water, all provided ad libitum, and in addition each bird was given a small bundle of heather (Calluna vulgaris) two or three times a week. The heather normally constituted about 5 to 10% of the dry weight of their diet. From March until July they were all fed on grouse " breeders " pellets. The fibre content of both types of pellets is higher (12% and 11% respectively) than in standard poultry foods so as to resemble the fibrous nature of the heather diet of wild grouse. The detailed composition of the diets is confidential, but both types contain all known nutrients in excess 1 Present address: Agricultural Research Council's Poultry Research Centre, King's Buildings, West Mains Road, Edinburgh EH9 3JS, Scotland. 16/5—D 471
Downloaded by [York University Libraries] at 07:16 01 February 2015
472
C. J. SAVORY
of comparable poultry requirements (National Research Council, i960; Agricultural Research Council, 1963). Food intake was measured on 1 d each week from June 1969 until August 1971. Generally four to six grouse of each sex were used, and the same individuals from week to week; if any one died it was replaced by a bird of about the same weight. The bundles of heather were removed and each bird was supplied with a known weight of maintenance pellets in a small feeding trough. The troughs, which had lids with holes to prevent spillage, were taken out at the end of 24 h and the remaining food weighed to find the weight eaten. Correction for any weight change due to moisture changes was made by using a control dish of weighed pellets, but at the most the change amounted to only 0-3% of the weight of food. In spring, when all the birds were fed on breeders pellets, food intake was expressed in terms of maintenance pellets for easy comparison with other times of year. When pellets of the different types were fed on consecutive days, the intake of breeders pellets was 92% of the intake of maintenance pellets. On the days when food intake was measured, air temperature and body weight were measured and the state of moult was noted. Seasonal changes in the plumage of adult grouse have been described by Wilson (1911). Old unmoulted primaries, new primaries wholly or partly in sheath and complete new primaries were counted, and also the state of moult was scored from o (no moult) to 5 (maximum, large areas of the body with >75% of feathers in moult). At most times of year, some birds had one or two very small feathers growing on their crowns, but they were considered insignificant and scored zero for body moult. In spring, the number and weight of eggs laid were also recorded. RESULTS
Body weight
The mean weights of hens in different months were significantly correlated (P
