2 results
Effect of feeding supplements on the intake and live-weight gain of male red deer given silage during winter
- J.R. Webster, I.D. Corson, R.P. Littlejohn
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- Journal:
- Animal Science / Volume 73 / Issue 3 / December 2001
- Published online by Cambridge University Press:
- 18 August 2016, pp. 555-561
- Print publication:
- December 2001
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The live-weight gain (LWG) of young male red deer in New Zealand naturally slows during winter and feeding diets of mainly silage appears to exacerbate this effect. We aimed to quantify the effect of feeding silage on intake and LWG during winter and the ability to improve LWG by feeding supplements, mainly in the form of barley. Seven groups of eight deer were maintained outside in gravelled enclosures and offered silage ad libitum for 94 days during winter. Six groups were given supplements (950 g barley with 50 g rapeseed meal per kg to make all diets isonitrogenous) at rates of proportionately 0·2, 0·4, 0·5, 0·6, 0·7 and 0·9 of the metabolizable energy (ME) intake of the group given only silage (0). The study also examined the effect of the winter treatments on subsequent LWG to slaughter weight whilst grazing on pasture during spring and into summer (102 days).
Increasing supplement intake resulted in a decrease in silage dry matter (DM) and ME intake (P < 0·001) and an increase in total ME intake (P < 0·01). The substitution rate for silage DM was 0·84 (s.e. 0·079). LWG during silage feeding was positively related (P < 0·01) to supplement intake with an increase of 6·21 g/day per MJ per day. LWG on pasture was not related to either supplement feeding rate or LWG during winter. LWG over the entire experiment was related (P < 0·01) to supplement feeding rate, with a final difference in live weight of 6 kg between 0 and 0·9 groups.
This study has confirmed that the LWG of young male deer is low during winter when given only silage and that feeding supplements increases total ME intake and LWG. The reduced LWG due to silage feeding was not compensated for on pasture during spring and summer, thus delaying the time to reach slaughter weight by approximately 1 month. High proportions of silage in the diet appear unsuitable for young male deer if the aim is to achieve rapid LWG during winter.
Effect of diet energy density and season on voluntary dry-matter and energy intake in male red deer
- J.R. Webster, I.D. Corson, R.P. Littlejohn, B.M. Masters, J.M. Suttie
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- Journal:
- Animal Science / Volume 70 / Issue 3 / June 2000
- Published online by Cambridge University Press:
- 18 August 2016, pp. 547-554
- Print publication:
- June 2000
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Food intake and growth of red deer is lower in winter than in spring and this reduces the efficiency of venison production. Rumen capacity is also lower during winter and this may contribute to the reduced food intake and therefore growth. In the present study, we investigated the ability of deer to regulate food intake during winter and spring by feeding diets of differing energy densities.
Six groups of eight male red deer calves were housed indoors in separate pens. Each group was given, ad libitum, a pelleted diet of a different energy density (8·5, 9·0, 9·5, 10·0, 10·5 and 11·0 MJ metabolizable energy (ME) per kg dry matter (DM) for groups 1 to 6 respectively) but the same amount of protein (156 g/kg DM). Food intake of each group was recorded every 2nd day and animals were weighed every 6 days from 17 May to 9 December. For seasonal comparisons, winter was defined as 24 May to 31 August and spring as 1 September to 9 December.
There was no difference (P > 0·05) between the mean live weights of the groups at any time during the study. Live-weight gain (LWG) reached a minimum on 4 July and was lower in winter than spring (161 v. 308 g/day, s.e.d. = 10·0, P < 0·001). LWG was positively related (P < 0·001) to diet ME during winter. DM intake (g/kg M0·75 per day) and ME intake (MJ ME per kg M0·75 per day) decreased until 16 July and increased thereafter. Mean DM intake was lower in winter than spring (83·5 v. 97·2 g/kg M0·75 per day, s.e.d. = 2·05, P < 0·001). DM intake increased as diet energy decreased (P < 0·001) in winter and spring with a steeper slope (P < 0·05) in spring than winter. ME intake was not related to diet ME (P > 0·005) and was lower in winter than spring (0·82 v. 0·95 MJ/kg M0·75 per day, s.e.d. = 0·25, P < 0·001). Maintenance energy requirement (MEm) across groups and seasons was calculated to be 0·45 (s.e. 0·22) MJ ME per kg M0·75 and the energy requirement for LWG (MEf) was 53 (s.e. 8·5) MJ/kg LWG. MEf was related (P < 0·01) negatively to diet ME during winter.
In summary, deer consuming diets with a wide range of energy densities, altered their DM intake, resulting in similar energy intakes and growth rates on all diets. Animals seemed less able to achieve this compensation in winter compared with spring when food intake increased to support the natural rise in growth rate at that time. These results indicate that deer have target growth rates and/or energy intakes that change with season, and are defended by adjusting food intake.