scholarly journals Voluntary food intake and reproduction

1987 ◽  
Vol 46 (2) ◽  
pp. 193-201 ◽  
Author(s):  
J. M. Forbes
1989 ◽  
Vol 48 (2) ◽  
pp. 449-457 ◽  
Author(s):  
B. P. Mullan ◽  
I. H. Williams

ABSTRACTThe level of body reserves in first-litter sows was manipulated by giving gilts one of three levels (high (H), medium (M) or low (L)) of food from selection (44 kg live weight) to parturition. The aim of this experiment was either to maintain or to mobilize these reserves during lactation (31·4 days) by feeding sows to appetite (high (H)) or 2·0 kg/day (low (L)).When the level of body reserves was increased prior to farrowing (171 kg live weight, 32 mm backfat) sows had a lower voluntary food intake during lactation than those animals that farrowed with a low level of body reserves (126 kg live weight, 20 mm backfat) (H-H v. L-H, 3·4 v. 4·9 kg/day; P < 0·001). Both groups had a normal return to oestrous activity after weaning (mean interval between weaning and mating of 14 days) but the heavier animals mobilized more of their body reserves (H-H −30·7 kg live weight, -4·3 mm backfat; L-H -3·6 kg live weight +0·9 mm backfat; P < 0·001). When food intake during lactation was restricted to 2·0 kg/day the interval between weaning and mating was increased by 50% regardless of the level of body reserves present at farrowing. For the same animals, there were insufficient body reserves to support milk production at the same level as for those animals given food t o appetite.


1986 ◽  
Vol 42 (3) ◽  
pp. 427-429 ◽  
Author(s):  
R. G. Campbell ◽  
M. R. Taverner

ABSTRACTThirty-six piglets were used to investigate the effect of six concentrations of dietary protein ranging from 155 to 235 g/kg, and corresponding dietary lysine concentrations from 10·1 to 15·4 g/kg, on the performance of pigs weaned at 28 days of age and growing between 7·5 and 20 kg live weight. Voluntary food intake was not significantly affected by dietary protein, and growth rate increased with increase in dietary protein and lysine up to 167 and 10·9 g/kg respectively (0·75 g lysine per MJ digestible energy (DE)). Food: gain ratio improved significantly with each increase in dietary protein and lysine up to 177 and 11·6 g/kg (0·79 g lysine per MJ DE) respectively.


2011 ◽  
Vol 72 (7) ◽  
pp. 918-923 ◽  
Author(s):  
Alfreda Wei ◽  
Andrea J. Fascetti ◽  
Cecilia Villaverde ◽  
Raymond K. Wong ◽  
Jon J. Ramsey

2000 ◽  
Vol 71 (1) ◽  
pp. 149-156 ◽  
Author(s):  
S. E. van Wieren

AbstractThe digestibility and voluntary intake of fibrous roughages and acorns was studied in six wild boar and five Meishan pigs. The neutral-detergent fibre (NDF) concentration of the diets ranged from 139 to 767 g/kg of the organic matter. Organic matter digestibility of acorns, mixed grass and wheat straw was higher in wild boar (P < 0·05) while voluntary food intake of the Meishan pigs was higher for mixed grass, hay and wheat straw (P < 0·05). Organic matter digestibility (P < 0·01) and NDF digestibility (P < 0·05) were both negatively related to NDF concentration of the diet. No relationship existed between voluntary food intake and NDF concentration of the diet. The apparent nitrogen (N) digestibility was positively related (P < 0·01) to dietary N while no relationship was found with dietary NDF. The negative effect of NDF on digestibility could only be partly explained by the lignin concentration of NDF. Much more important was the lower efficiency of the carbohydrate fermentation in the caecum and colon when compared with the direct absorption of glucose from the small intestine. It was estimated that digestible NDF at a maximum contributed proportionately 0·26 to the metabolizable energy intake of the animals. It was concluded that wild boar and domestic pigs should be able to maintain themselves on an all fresh grass diet when NDF concentration of the diet does not exceed about 550 g/kg and N concentration is not too low.


1970 ◽  
Vol 12 (4) ◽  
pp. 669-671 ◽  
Author(s):  
Janet Z. Foot ◽  
J. F. D. Greenhalgh

SUMMARYThe relation between the weight of the alimentary tract contents and the weights of body fat and the uterus was examined in 23 Blackface ewes. Six ewes were not pregnant, five had single foetuses and 12 had twins. The pregnant ewes were slaughtered three or four days before their expected lambing date. There was a negative relation between uterine weight or body fat weight and the weight of alimentary tract contents. The effect of uterine weight was small and not significant when only the pregnant animals were considered. It was unlikely that physical restriction of the alimentary tract by the uterus played more than a minor role in limiting voluntary food intake under the conditions of this experiment.


1993 ◽  
Vol 121 (2) ◽  
pp. 255-263 ◽  
Author(s):  
J. H. Niezen ◽  
T. N. Barry ◽  
J. Hodgson ◽  
P. R. Wilson ◽  
A. M. Ataja ◽  
...  

SUMMARYTwo experiments were conducted at the Massey University Deer Unit, New Zealand in 1990 and 1991 to evaluate the performance of lactating red deer hinds and their calves grazing conventional perennial ryegrass-based pastures, red clover or chicory. In both experiments, hind and calf performance was evaluated from 1 month post-parturition over a 2½ month summer period to weaning at 3½ months of age.In Expt 1, hinds and calves were grazed on low (5·4 kg dry matter (DM)/hd/day), medium (10·8) or high (16·4) allowances of red clover, or on a medium allowance of a conventional ryegrass/white clover sward (9·9 DM/hd/day). In Expt 2, hinds and calves grazed equal DM allowances (12 kg DM/hd/day) of perennial ryegrass/white clover, chicory or red clover.Red clover generally had higher organic matter digestibility (OMD) and higher total N than ryegrass/white clover, and when grazed at equal DM allowances, promoted higher voluntary food intake in the hinds, increased calf growth (430 v. 330 g/day) and increased hind liveweight change. Although decreasing the red clover allowance in Expt 1 slightly but non-significantly decreased hind voluntary food intake and decreased both calf and hind liveweight change, all low red clover values were still consistently higher than all ryegrass/white clover values (P < 0·05). In Expt 2, chicory was of higher OMD and ash content than red clover but N content was lower and similar to ryegrass/white clover. Chicory promoted lower levels of calf liveweight change than red clover but higher than ryegrass/white clover. Hind liveweight change on chicory was lower than on red clover and was similar to ryegrass/white clover. It was concluded that red clover offers potential as a special purpose forage for deer production and that further experimental work is needed with chicory.


1988 ◽  
Vol 119 (3) ◽  
pp. 413-420 ◽  
Author(s):  
J. D. Curlewis ◽  
A. S. I. Loudon ◽  
J. A. Milne ◽  
A. S. McNeilly

ABSTRACT Seventeen red deer hinds were housed in individual pens and from 28 February until 11 November were injected each week with vehicle (group A; n = 6) or 5 (group B; n = 6) or 12·5 mg (group C; n = 5) of a long-acting formulation of bromocriptine. Liveweight and voluntary food intake (VFI) were recorded for each hind, and blood was collected for determination of progesterone, prolactin, tri-iodothyronine (T3) and cortisol concentrations by radioimmunoassay. Treatment with the high dose of bromocriptine was associated with a significant (P <0·05) reduction in VFI, with the effect being greatest between March and July. There was no treatment effect on liveweight, but there was a significant (P <0·01) interaction between time and treatment due to the faster rate of weight gain in control animals at the beginning of the experiment. Changes in liveweight could be explained by changes in VFI rather than by changes in the efficiency of utilization of intake. Termination of the breeding season was significantly (P <0·01) delayed by 54 days in group C hinds. Growth of the summer coat and subsequent winter coats was delayed by 1 and 3 months respectively in group C hinds, and in groups B and C the duration that animals were in summer coat was increased by about 1 month. The seasonal increase in prolactin concentrations was seen in all groups, but levels were significantly (P <0·05) lower in group C hinds. Concentrations of T3 and cortisol were not affected by bromocriptine. J. Endocr. (1988) 119, 413–420


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