Artificial rearing as a system for evaluating male lambs

1978 ◽  
Vol 26 (1) ◽  
pp. 31-38 ◽  
Author(s):  
D. A. R. Davies ◽  
J. B. Owen ◽  
J. L. Read
Keyword(s):  
Growth Rate ◽  
Food Intake ◽  
Performance Testing ◽  
Food Conversion ◽  
Artificial Rearing ◽  
Breed Differences ◽  
Variable Influence ◽  
Late Performance ◽  
Variable Performance ◽  
Milk Feeding

ABSTRACTThe use of an artificial rearing system to provide controlled environment conditions for performance testing of male lambs was investigated in two trials. A sample of lambs from 5 fat-lamb sire breeds was included.Performance during the initial restricted milk-feeding period was uniform but large differences in solid food intake gave variable performance in the adjustment period immediately following weaning. Lambs were evaluated from 40 days onwards in terms of growth rate and efficiency of food conversion. Some breed differences were significant and the variation within groups was sufficiently high to suggest that performance might be improved by within-group selection.Estimates from Trial 2 show that food conversion efficiency was related to growth rate, but early and late performance in the evaluation period were not correlated (r = 0·12, 0·16 and 0·14 for growth rate, food intake and efficiency, respectively). Some refinements of the method are suggested, and it is concluded that the system could provide suitable conditions for testing male lambs at an early age without the variable influence of the dam.

Selection for efficient lean growth in a pig herd

1981 ◽  
Vol 32 (4) ◽  
pp. 681 ◽  
Author(s):  
CP McPhee
Keyword(s):  
Growth Rate ◽  
Food Intake ◽  
Performance Test ◽  
Subcutaneous Fat ◽  
Performance Testing ◽  
Restricted Feeding ◽  
Food Conversion ◽  
Muscle Area ◽  
Eye Muscle ◽  
Lean Growth

A pig herd was selected for 6 years by using an economic index combining growth rate, food conversion efficiency and carcass leanness. These three traits were all measured in a performance test which permitted appetite variation between pigs to be expressed. Boars selected with an intensity of 118 were used for 6 months, and sows with an intensity of 114 were kept for two farrowings. An unselected control herd was maintained concurrently. To measure selection response, selected (S) and control (C) pigs were compared as they grew from 25 to 90 kg liveweight on ad lib. and restricted feeding during the last 2 years of selection. The following significant (P < 0.05) responses occurred in the selection herd: (i) A slight increase in growth rate on restricted feed, balanced by a similar decrease on ad lib, feeding. (ii) A decline in food conversion ratio of 5 % (C, 2.79; S, 2.65) due mainly to a reduction in appetite. (On ad lib. feeding, food intake per day declined by 6 % (C, 2.30 kg/d; S, 2.16 kg/d.)). (iii) A decline in average subcutaneous fat depth by 11 % (C, 27.8 mm; S, 24.7 mm) and in fat dissected from the ham by 7 % (C, 2.80 kg; S, 2.61 kg). (iv) An increase in estimated lean in the carcass by 2% (C, 30.3 kg; S, 31.0 kg). (v) A decline in dressing percentage of the carcass by 1 % (C, 77.1 %; S, 76.2 %). There was no change in eye muscle area or carcass length. The results are discussed in terms of changes in the ratio of food intake to lean growth. In the group fed ad lib., this ratio declined by 7 %, mainly because of a decline in food intake. On restricted feeding it fell by 6 %, mainly owing to an increase in lean growth. That portion of the selection effort absorbed in reducing food intake may have been more profitably directed to increasing lean growth by suppressing appetite variation during performance testing, rather than allowing it to be expressed.

Genetic components of growth and ultrasonic fat depth traits in Meishan and Large White pigs and their reciprocal crosses

1992 ◽  
Vol 54 (1) ◽  
pp. 105-115 ◽  
Author(s):  
C. S. Haley ◽  
E. d'Agaro ◽  
M. Ellis
Keyword(s):  
Growth Rate ◽  
Food Intake ◽  
Performance Test ◽  
Subcutaneous Fat ◽  
Additive Effect ◽  
Food Conversion ◽  
Large White ◽  
Male And Female ◽  
Ad Libitum ◽  
The Impact

AbstractGenes from the Chinese Meishan pig have the potential to enhance reproductive performance of European pigs. In order to allow prediction of the impact of Meishan genes in a range of alternative improvement programmes all traits of economic importance must be evaluated and genetic crossbreeding effects estimated. Entire male and female pigs of four genotypes, purebred Meishan (MS) and Large White (LW) pigs and both reciprocal Fl crossbred genotypes (MS ♂ × LW ♀ and LW ♂ × MS ♀), were farrowed in Edinburgh and subsequently performance tested at either Edinburgh or Newcastle. In Edinburgh, animals were penned in groups of four and fed ad libitum between pen mean weights of approximately 30 and 80 kg. At the end of test fat depths at the shoulder, last rib and loin were measured ultrasonically. In Newcastle, animals were penned in groups of six and fed ad libitum between pen mean weights of approximately 30 and 70 kg. Genotypic means and genetic crossbreeding effects (additive and heterosis direct effects and additive maternal effects) were estimated using restricted maximum likelihood.When compared with the LW, the direct additive effect of genes from the MS produced increased growth rate up to the time of weaning, no change in growth rate between weaning and start of test and greatly reduced growth rate during the performance test. The maternal additive effect of genes from the MS was to reduce growth rate up to the time of weaning, with little effect thereafter. There was substantial direct heterosis for growth rate in all periods measured, but heterosis was less in males than in females during the performance test. The combined effect was such that, within sex, the LW and the two crossbred genotypes were of similar ages when they reached 70 and 80 kg, but MS pigs were 38 to 60 days older. The direct additive effect of MS genes was to increase subcutaneous fat levels and there was little evidence for the effects of maternal genes or direct heterosis on these traits. There was a direct additive effect of MS genes reducing food intake and increasing food conversion ratio and there was direct heterosis for increased food intake. There were significant interactions between genotype and sex. Male and female LW pigs had a similar performance but male MS pigs had slower growth rates on the performance test with lower food intakes, food conversion ratios and subcutaneous fat levels than the females.

Effect of nutrient density and group size on the performance of growing and finishing pigs given food using single-space feeders

2000 ◽  
Vol 71 (2) ◽  
pp. 281-288 ◽  
Author(s):  
J. V. O’Doherty ◽  
M. P. McKeon
Keyword(s):  
Growth Rate ◽  
Food Intake ◽  
Carcass Characteristics ◽  
Dietary Treatment ◽  
Conversion Ratio ◽  
Finishing Pigs ◽  
Food Conversion ◽  
Nutrient Density ◽  
Daily Food ◽  
Main Effects

AbstractA 2 ✕ 2 ✕ 3 factorial arrangement of treatments used 522 boars to examine the main effects and interactions of season (spring v. summer), number of pigs per pen with a single-space feeder (13 or 16 pigs per pen with a singlespace feeder; 0·78 m2 per pig v. 0·65 m2 floor space per pig) and nutrient density of the diet (12·5 g lysine per kg and 14·0 MJ digestible energy (DE) per kg from 38 kg to slaughter (high), 12·5 g lysine per kg and 14·0 MJ DE per kg during the growing phase and 10·0 g lysine per kg and 13·6 MJ DE per kg during the finishing phase (split) and 10 g lysine per kg and 13·6 MJ DE per kg from 38 kg to slaughter (low)) on the performance and carcass characteristics of growing and finishing pigs. The smaller group of pigs had a higher food intake during the grower-finisher period than the high stocked pigs (P < 0·01). The pigs had a higher lysine intake in the spring than in the summer months (P < 0·05). Differences in daily food intake for the smaller group of pigs were reflected in increased growth rate during the grower-finisher period (P < 0·001). However these pigs had a poorer food conversion ratio during the grower-finisher period (P < 0·05) than the bigger group of pigs. The pigs offered the high specification and split-fed diets had better growth rate (P < 0·05) than the pigs given the low specification diet during the grower and finisher period. There was a significant two-way interaction in growth rate between dietary treatment and season during the finisher period (P < 0·01). The pigs given the high specification diet had a better growth rate (P < 0·001) than the pigs given the low diets during the summer months. However, the high specification diet depressed growth rate during the spring months (P < 0·05). The pigs had a lower backfat and higher lean meat in the summer than in the spring months (P < 0·05).

Management strategies to maximize pigmeat output: effect of group size and split-marketing

2005 ◽  
Vol 81 (1) ◽  
pp. 171-177 ◽  
Author(s):  
M. K. O'Connell ◽  
P. B. Lynch ◽  
J. V. O'Doherty
Keyword(s):  
Growth Rate ◽  
Food Intake ◽  
Group Size ◽  
Unit Area ◽  
Live Weight ◽  
Conversion Ratio ◽  
Carcass Weight ◽  
Food Conversion ◽  
Food Conversion Ratio ◽  
2D And 3D

AbstractTwo experiments were completed with grower-finisher pigs to determine if pigmeat output, as measured by carcass gain per m2 per year, could be increased, by 1: increasing group size or 2: split-marketing pen groups. In experiment 1, 390 pigs (mean initial live weight 36·7 (s.d. 1·99) kg) were assigned to one of three treatments each with 10 replicates: 11, 13 or 15 pigs per single-sex group in pens measuring 11·04 m2. Space allowance was 1·00, 0·85 and 0·74 m2 per pig, respectively. Pelleted food was provided ad libitum. There were no differences (P > 0·05) between group sizes in growth rate, food intake, food conversion ratio, carcass growth and carcass food conversion ratio, backfat and muscle depth or carcass lean content. Pigmeat output per unit area increased with each increase in group size (234, 279 and 314 kg/m2 per year for 11, 13 and 15 pigs: P < 0·001). In experiment 2, 26 groups of 13 pigs (mean initial live weight 38·3 (s.d. 2·15) kg) were assigned to one of three treatments: 1D - group sold on 1 day (no. = 9), 2D - group sold over 2 days (14 days apart, no. = 10), or 3D - group sold over 3 days (each 7 days apart, no. = 7). Pigs were given a standard liquid diet three times daily. No differences (P > 0·05) were observed between treatments for overall growth rate, food intake, food conversion ratio, carcass weight, carcass lean content, backfat and muscle depth, carcass growth and carcass food conversion ratio or killing-out proportion of pigs. Split-marketing increased cycle length (67·7, 75·9 and 76·8 days for 1D, 2D and 3D, respectively; P < 0·001). Live and carcass daily growth rates per pig place decreased with increase in number of sale days (live: 772, 680, 670 g/day and carcass: 658, 575, 571 g/day; P < 0·001). Carcass gain per unit area decreased in split-marketed groups (358, 318, 312 kg/m2 per year for 1D, 2D and 3D, respectively: P < 0·05). Carcass weight variation (s.d.) within pen decreased with each increase in number of sale days (s. d. 5·28, 3·81 and 1·74, respectively; P < 0·001). In conclusion, pigmeat output, as measured by carcass gains per m2 per year, was improved with increase in group size and by marketing all pigs in a group on a single day.

Effects of Intermediate and Low Salinity Conditions on Growth Rate and Food Conversion of Atlantic Cod (Gadus morhua)

1994 ◽  
Vol 51 (7) ◽  
pp. 1569-1576 ◽  
Author(s):  
Yvan Lambert ◽  
Jean-Denis Dutil ◽  
Jean Munro
Keyword(s):  
Growth Rate ◽  
Food Intake ◽  
Growth Rates ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Food Conversion ◽  
Coastal Regions ◽  
Low Salinity ◽  
Feeding Regimes ◽  
Food Conversion Efficiency

Growth rates of Atlantic cod (Gadus morhua) were measured under different salinity conditions to test the hypothesis that growth would be best in an isosmotic environment. The results of two experiments (spring and autumn 1991) conducted at three different salinities (7, 14, and 28‰) and two feeding regimes indicate a significant effect of salinity and ration on growth rate. Within each experiment, growth rates were highest for cod maintained in intermediate salinity conditions (14‰). Growth rates in low salinity conditions (7‰) were higher than in seawater (28‰) during the spring, but during the autumn, growth rates of cod held under low salinity conditions and in seawater were similar. Higher growth rates at lower salinities resulted from an increase in food conversion efficiency. They were not associated with an increase in food intake, changes in composition (proteins, lipids, or water), or relative allocation of energy to the tissues (muscle, liver, and gonads) of cod. The results indicate that rearing cod at intermediate salinities, such as would occur in estuaries or coastal regions, could confer an advantage for cod aquaculture.

Selection for components of efficient lean growth rate in pigs 4. Genetic and phenotypic parameter estimates and correlated responses in performance test traits with ad-libitum feeding

1994 ◽  
Vol 59 (2) ◽  
pp. 281-291 ◽  
Author(s):  
N. D. Cameron ◽  
M. K. Curran
Keyword(s):  
Growth Rate ◽  
Food Intake ◽  
Performance Test ◽  
Food Conversion ◽  
Daily Food Intake ◽  
Lean Growth ◽  
Daily Food ◽  
Genetic And Phenotypic Correlations ◽  
Selection For ◽  
Ad Libitum Feeding

AbstractGenetic and phenotypic parameters and correlated responses in performance test traits were estimated for populations of Large White (LW) and British Landrace (LR) pigs tested in Edinburgh and Wye respectively, to four generations of divergent selection for lean growth rate (LGA), lean food conversion (LFC) and daily food intake (DFI) with ad-libitum feeding.There were differences between the two populations in genetic parameters, as LW heritabilities for growth rate, daily food intake and backfat depths were higher and the correlation between growth rate and backfat was positive for LW, but negative for LR. However, heritabilities, genetic and phenotypic correlations were generally comparable between selection groups, within each population. Genetic and phenotypic correlations indicated that animals with high daily food intakes were faster growing, had positive residual food intakes (RFI), were fatter with higher food conversion ratios. RFI was highly correlated with daily food intake and food conversion ratio, but phenotypically independent of growth rate and backfat, as expected.Selection for LGA, in LW and LR populations, increased growth rate (54 and 101 g/day), but reduced backfat (−3·9 and −2·0 mm), food conversion ratio (−0·23 and −0·25) and total food intake (−11·8 and −12·6 kg). There was no change in daily food intake in LW pigs (−19 g/day), but daily food intake increased in the LR pigs (69 g/day). With selection for LFC in LW and LR populations, there was no response in groivth rate (9 and 9 g/day), but backfat (−4·1 and −2·1 mm), total (−6·6 and −11·8 kg) and daily food intake (−90 and −172 g) were reduced, as animals had lower food conversion ratios (−0·13 and −0·22). LW and LR pigs selected for DFI ate more food in total (6·8 and 5·9 kg) and on a daily basis (314 and 230 g), grew faster (94 and 51 g/day) and had higher food conversion ratios (0·12 and 0·13). Backfat was increased in LW pigs (3·7 mm), but not in the LR population.In general, efficiency of lean growth was improved by increasing groivth rate, with little change in daily food intake from selection for LGA, but was primarily due to reduced daily food intake with selection on LFC.

The performance of Hereford × Friesian offspring of bulls selected for lean growth rate and lean food conversion efficiency

1992 ◽  
Vol 54 (1) ◽  
pp. 23-30 ◽  
Author(s):  
S. C. Bishop ◽  
J. S. Broadbent ◽  
R. M. Kay ◽  
I. Rigby ◽  
A. V. Fisher
Keyword(s):  
Growth Rate ◽  
Food Intake ◽  
Genetic Correlations ◽  
Conversion Ratio ◽  
Carcass Composition ◽  
Control Line ◽  
Food Conversion ◽  
Breeding Values ◽  
Lean Growth ◽  
Food Conversion Ratio

AbstractThe performance of Hereford × Friesian calves sired by Hereford bulls selected for either lean growth rate (LGR) or lean food conversion ratio (LFCR), or by unselected Hereford bulls, was evaluated on 327 calves on three farms over 2 years. Animals started test at 130 days of age on average and remained on test for approximately 300 days, whereupon all animals were slaughtered and carcass dissections were undertaken. Individual food intake was measured on tioo of the farms (189 animals), but only intake per pen of animals was measured on the third farm and individual food intake had to be estimated. LGR, LFCR and other traits describing performance were calculated from the growth, food intake and carcass composition data.If no breed or environment interactions exist it is expected that proportionately 0-5 of the genetic differences between selected and control line bulls would be transmitted to their offspring. For the LGR and LFCR line bulls these values were 0·38 and 0·44, respectively, however the LGR value had a much smaller confidence interval. Genetic correlations derived from regressing breeding values predicted from offspring performance on breeding values predicted from the bulk's own performance in the selection experiment were 0·62 (s.e. 0·28) and 0·96 (s.e. 0·28) for LGR and LFCR, respectively. Heritabilities were: live-weight gain on test, 0·27; daily gain, 0·48; food intake, 0·06; food conversion ratio, 0·46; predicted carcass lean content, 0·10; killing-out proportion, 0·10; LGR, 0·36 and LFCR, 0·48.

The influence of dietary protein and level of feeding on the growth performance and carcass characteristics of entire and castrated male pigs

1982 ◽  
Vol 35 (2) ◽  
pp. 177-184 ◽  
Author(s):  
R. G. Campbell ◽  
R. H. King
Keyword(s):  
Growth Rate ◽  
Food Intake ◽  
Growth Performance ◽  
Dietary Protein ◽  
Protein Level ◽  
Carcass Characteristics ◽  
Live Weight ◽  
Conversion Ratio ◽  
Food Conversion ◽  
Ad Libitum

ABSTRACT1. Three isocaloric diets containing 170, 210 or 231 g crude protein per kg were given at two levels, and offered ad libitum to entire and castrated male pigs growing from 20 to 70 kg live weight.2. Between 20 and 45 kg, growth rate improved with each increase in level of feeding (P < 005) and, on the ad libitum treatment the food intake and growth performance of both entire and castrated pigs were similar. On the restricted feeding treatments the growth performance of entire, but not of castrated pigs, improved when dietary protein was raised from 170 to 210g/kg (P < 005).3. During the live-weight periods 45 to 70 and 20 to 70kg, raising food intake improved growth rate (P < 005) but increased the food conversion ratio and carcass fat measurements at 70 kg (P < 0·05). However, food conversion ratio and the majority of carcass characteristics of entire pigs fed ad libitum were equivalent to those of castrated pigs fed at the lowest level.4. Dietary protein level had no significant effect on growth performance from 20 to 70 kg or on carcass fat measurements at the latter weight. However, each increase in dietary protein in the live-weight period 45 to 70 kg depressed the performance of castrated pigs (P < 0·05) while that of entire pigs was reduced when the protein level of the diet was raised from 210 to 231 g/kg.

A note on the growth and food consumption of crossbred lambs of five sire breeds

1983 ◽  
Vol 37 (1) ◽  
pp. 137-140 ◽  
Author(s):  
J. A. Woolliams ◽  
G. Wiener
Keyword(s):  
Growth Rate ◽  
Energy Efficiency ◽  
Weight Gain ◽  
Food Intake ◽  
Food Consumption ◽  
Fish Meal ◽  
Live Weight ◽  
Food Conversion ◽  
Live Weight Gain ◽  
Ad Libitum

ABSTRACTLambs, 8 weeks of age, the offspring of sires of the Scottish Blackface, East Friesland, Finnish Landrace, Suffolk and Texel breeds mated to Scottish Blackface females as a common maternal breed were fed ad libitum on a concentrate containing barley and fish meal for 14 weeks. Live weight and food intake were measured at intervals of 2 weeks.Live-weight gain varied between sire breeds, Suffolk crosses having the greatest growth rate and the Blackface lambs the least, but there were no significant differences in their food conversion ratios. Food intakes were compared with those predicted by two methods. When the only criteria for prediction were live weight and the metabolizability of the diet the prediction was poor, whereas very accurate agreement was found when the criteria for prediction included consideration of the changes in energy efficiency with food intake and with maturity.

Influence of shearing and level of concentrates offered on the performance of lambs

1990 ◽  
Vol 1990 ◽  
pp. 164-164
Author(s):  
H.J. Black ◽  
D.M.B. Chestnutt
Keyword(s):  
Growth Rate ◽  
Food Intake ◽  
Conversion Efficiency ◽  
Food Conversion ◽  
Ad Libitum ◽  
Food Conversion Efficiency ◽  
Voluntary Food Intake

It has been clearly established that shearing ewes during pregnancy increases lamb birthweight (Austin and Young, 1971; Rutter, Laird and Broadbent, 1971; Black and Chestnutt, 1990). Fewer studies have examined the response of fattening lambs to shearing although both Salman and Owen (1981) and Marai, Nowar and Bahgat (1987) noted a significant increase in growth rate. This was accompanied by an increase in voluntary food intake and consequently little change in the food conversion efficiency.The objective of these experiments was to study the influence of shearing on voluntary food intake and growth rate of fattening lambs offered various levels of concentrate feeding plus ad libitum forage.

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