Long-term effect of selection for litter size and feeding programme on the performance of reproductive rabbit does 1. Pregnancy of multiparous does

AbstractA total of 166 crossbred does were used to study the possible long term effect of two types of crossbred does (H1 v. H2, old and current generations, respectively) from the cross of different generations of lines selected for litter size, the use of a feeding programme based on a low-energy diet during the rearing and the administration of a high-energy diet during reproductive life, on the performance and body condition of multiparous pregnant does. Selection did not affect the live weight (LW) of does at the effective artificial insemination (AI; 4257 g), the LW change (+12·3 g/day) and food intake (172 g dry matter (DM) per day) until the 28th day of pregnancy. However, H2 does showed greater LW losses during the pre-partum period than H1 does (120+g;P<0·05), perhaps related to their higher prolificacy (+1·1 total pups born;P<0·05). H2 does showed a higher perirenal fat thickness (PFT) at first AI (+0·12 mm;P<0·05) than H1 does, these differences disappearing at effective AI. Females given a high-energy reproduction diet showed a lower LW at effective AI than those receiving a medium-energy diet (4210, 4305 g, respectively;P<0·05). However, type of reproduction diet did not affect the LW and PFT changes of pregnancy does, reaching partum with a similar PFT (8·83 v. 8·93 mm) and maintaining the differences in LW. Pregnant does given high-energy diet consumed 20 g DM and 1·4 g digestible protein per day less than does receiving medium-energy diet until the 28th day of pregnancy, but their digestible energy (DE) intake was significantly higher (+78 kJ DE per day;P<0·05). Does given high-energy diet showed a significantly lower litter size at birth (−0·7 pups;P<0·05), although there were no significant differences in the number of pups born alive (9·54 and 9·76 pups for high and medium-energy diets, respectively). Pups from does given high-energy diet were slightly weightier than those from medium-energy diet (+5·4 g;P<0·05). Multiparous pregnant does that received a low-energy diet ad libitum during the rearing period and first pregnancy showed a higher LW at effective AI (+137 g LW;P<0·05) but a lower PFT (−0·26 mm;P<0·05) than those females that received a medium-energy diet restricted during this same period. These differences were maintained at parturition (+142 g LW and −0·20 mm;P<0·05). Feeding programme during rearing affected neither the food intake of multiparous pregnant does until the 28th day of pregnancy, nor the litter size and weight at birth. The interval between parturitions was not affected by the selection for litter size or the reproduction diet received, but was longer for does that received the low-energy diet ad libitum during the rearing period (+2·9 days;P<0·05). In conclusion, rabbit selection programmes by litter size seem to be working well, but high energy reproduction diets, frequently used to cover their higher energy requirements, must be used carefully out of lactation in the long term to avoid a reduction in litter size.

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Long-term effect of selection for litter size and feeding programme on the performance of reproductive rabbit does 2. Lactation and growing period

Animal Science ◽

10.1079/asc200688 ◽

2006 ◽

Vol 82 (5) ◽

pp. 751-762 ◽

Cited By ~ 14

Author(s):

F. Quevedo ◽

C. Cervera ◽

E. Blas ◽

M. Baselga ◽

J. J. Pascual

Keyword(s):

Food Intake ◽

Litter Size ◽

Milk Yield ◽

Body Condition ◽

Live Weight ◽

High Energy ◽

Term Effect ◽

Growing Period ◽

Long Term Effect

AbstractA total of 166 crossbred does were used to study the possible long-term effect of two types of crossbred does (H1v.H2, old and current generations, respectively) from the cross of different generations of lines selected for litter size, the use of a rearing programme based on a low-energy diet, and the administration of a high-energy diet during reproductive life, on the performance and body condition of lactating rabbit does and their litters until slaughter. The body condition of the reproductive rabbit does increased in the successive cycles to the fourth parturition, being maintained from this moment on. Animals more selected for litter size at weaning presented a greater food intake (+3%;P<0·05) and milk yield (+6%;P<0·05) during the first 21 days of lactation, which could be related to greater maternal aptitude. The difference in the weight of pups at slaughter time (+24 g for H2 respect to H1 pups) was one third lower than that expected from the generation response of the paternal line (0·45 g/day), perhaps related to the different enteropathy incidence depending on the genetic type. The use of a high-energy diet during the reproduction period increased the milk yield (+22%;P<0·05) of does, as the growth (+16 g at weaning day;P<0·05) and survival index (+2%;P<0·05) of the litters during lactation, but could produce a more sudden weaning of pups as a consequence of their lower pre-weaning food intake (−42%;P<0·05), which has been related with a greater health risk index during the growing period (+4·2%;P<0·05). Reproductive does given a high fibre diet during the rearing period (from 3 kg live weight to 28th day of the first pregnancy) reached parturition with a higher live weight than does that received a moderate energy diet restricted during this same period (+142 g;P<0·05). All other parameters controlled for the lactating does and their litters were not affected by the type of diet received during the rearing period. Females that were not effectively mated at first AI (11 dayspost partum) showed a greater increase in their perirenal fat thickness between partum and the 11th day of lactation than those lactating females that showed an effective mating (+0·22v.+0·37 mm, respectively;P<0·05).

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Factors affecting voluntary feed intake in pigs. 3. The effect of a period of feed restriction, nutrient density of the diet and sex on intake, performance and carcass characteristics

Animal Science ◽

10.1017/s0003356100026386 ◽

1968 ◽

Vol 10 (4) ◽

pp. 345-357 ◽

Cited By ~ 25

Author(s):

D. J. A. Cole ◽

J. E. Duckworth ◽

W. Holmes ◽

A. Cuthbertson

Keyword(s):

Feed Intake ◽

Compensatory Growth ◽

Live Weight ◽

High Energy ◽

Low Energy ◽

Digestible Energy ◽

Voluntary Feed Intake ◽

Nutrient Density ◽

Ad Libitum ◽

Low Energy Diet

1. Over the weight range 23–50 kg live weight, pigs were fed either ad libitum or to a restricted scale. From 59 to 91 kg live weight, eight pairs of barrows and eight pairs of gilts were fed on each of two diets varying in nutrient density. The effects of feed restriction, nutrient density of the diet and sex on voluntary feed intake, performance and carcass characteristics were studied.2. Pigs which had been restricted grew more slowly and contained less fat and more lean at 50 kg live weight.3. When restricted pigs were offered feed ad libitum from 59 to 91 kg live weight they ate more and had higher daily intakes of digestible energy than pigs liberally fed in early life.4. There was evidence of compensatory growth in pigs which had received the restricted diet, but there was no significant difference in feed utilization between restricted and ad libitum pigs. It was concluded that the compensatory growth was largely the result of increased appetite.5. Pigs finally fed on a low energy diet, in comparison with those on a high energy diet, ate more feed but less digestible energy indicating that appetite was physically limited. Efficiency of conversion of digestible energy to live weight was similar on both treatments. A higher proportion of acetic acid was produced in the caecum of pigs fed the low energy diet. Pigs receiving the low energy diet had lower killing-out percentages not entirely caused by differences in the weight of the gut and its contents. The carcasses of pigs on the low energy diet were leaner than those on the high energy diet.6. Barrows consumed more digestible energy per day than gilts, required more feed and digestible energy per unit live-weight gain, had lower killing-out percentages, shorter carcasses, larger backfat measurements and smaller eye-muscle areas as estimated by A × B measurements. Barrow carcasses contained less dissected lean and more fat than gilts' carcasses.7. The results are discussed in relation to other work and it is concluded that voluntary feed intake is influenced by the nutrient density of the diet and the level of energy requirement of the pig, which may be affected by previous nutritional history.

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Effect of selection for litter size and feeding programme on the performance of young rabbit females during rearing and first pregnancy

Animal Science ◽

10.1079/asc40850161 ◽

2005 ◽

Vol 80 (2) ◽

pp. 161-168 ◽

Cited By ~ 18

Author(s):

F. Quevedo ◽

C. Cervera ◽

E. Blas ◽

M. Baselga ◽

C. Costa ◽

...

Keyword(s):

Energy Intake ◽

Litter Size ◽

High Energy ◽

Young Female ◽

Low Energy ◽

Young Rabbit ◽

Foetal Growth ◽

Litter Traits ◽

Moderate Energy ◽

Selection For

A total of 166 crossbred young female rabbits were used to study the effect of two types of crossbred does (H1 v. H2, old and current generations, respectively) from the cross of different generations of maternal lines selected for litter size, the use of a feeding programme based on a low energy rearing diet (F) and the presentation of a high-energy dietpre-partum(E) on the performance of young rabbit females until their first parturition and on the main litter traits at first kindling. Perirenal fat was thicker at the age of 3 months for H2 than for H1 does, but this difference disappeared at the first insemination (4·5 months). H2 does had a significantly larger total number and number of live pups at birth (+2·06 live pups) than H1, higher than expected (+1·06). As this greater foetal growth was obtained for a similar energy intake of does, possible differences may exist in partitioning and/or effficiencies of dietary and body energies in favour of foetal growth as the genetic propensity for litter size increased. The use of a low-energy diet significantly reduced the growth of does during the rearing period (−294 g), but they showed a greater compensatory growth during the first 4 weeks of gestation (+79 g) as a consequence of their higher energy intake, without any retardation in their reproductive development. Does receiving diet F until 28th day of gestation showed a significantly greaterpre-partumenergy intake and their number of pups born alive was lower (−1·3 pups). Finally, the litters of females receiving diet Epre-partumand during lactation had lower mortality during the 1st week (26·9 v. 42·9% dead pups) and throughout lactation than those receiving a moderate energy diet.

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Long-term effect of nutritional counselling on desired gain in body mass and lean body mass in elite athletes

Applied Physiology Nutrition and Metabolism ◽

10.1139/h11-051 ◽

2011 ◽

Vol 36 (4) ◽

pp. 547-554 ◽

Cited By ~ 6

Author(s):

Ina Garthe ◽

Truls Raastad ◽

Jorunn Sundgot-Borgen

Keyword(s):

Body Composition ◽

Weight Gain ◽

Strength Training ◽

Body Mass ◽

Elite Athletes ◽

Term Effect ◽

Nutritional Guidance ◽

Long Term Effect ◽

Ad Libitum

Lean body mass (LBM) is important in power-related sports. In athletes with heavy training loads and competitions, it may be difficult to increase and maintain LBM during the season. The purpose of this study was to evaluate the long-term effects on body composition after an 8–12 week weight-gain period with or without nutritional guidance. Twenty-one elite athletes where randomized to 1 of 2 groups: the nutritional counselling group (NCG; n = 12, 18.5 ± 1.7 y, 67.8 ± 7.4 kg) and the ad libitum group (ALG; n = 9, 19.6 ± 2.7 y, 74.2 ± 5.7 kg). The NCG followed a meal plan that provided a surplus of 506 ± 84 kcal·day–1, whereas the ALG had an ad libitum energy intake (EI) during the strength-training (4 sessions per week) intervention. Body mass (BM) and body composition were measured pre- and postintervention, and 6 and 12 months after the intervention. EI in the NCG was normalized after 12 months, whereas EI in the ALG was unchanged during or after the intervention. BM increased more in the NCG than in the ALG during the intervention (4.3% ± 0.9% vs. 1.0% ± 0.6%) and after 12 months (6.0% ± 0.9% vs. 1.8% ± 0.7%). LBM increased in the NCG during the intervention (2.8% ± 0.5%) and after 12 months (4.4% ± 1.0%), whereas LBM in the ALG was unchanged. The NCG managed to maintain and increase BM and LBM after the intervention period. Hence, the focus on nutritional guidance, in addition to strength training, seems to be preferable for obtaining the long-term effect of weight gain in athletes.

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