Grassland performance of Hereford cattle selected for rate and efficiency of lean gain on a concentrate diet

1993 ◽  
Vol 56 (3) ◽  
pp. 311-319 ◽  
Author(s):  
S. C. Bishop

AbstractThe performance of 273 Hereford calves from lines previously selected for lean growth rate (LGR) or lean food conversion efficiency (LFCR), on a concentrate diet, was evaluated on a grassland diet over a period of 3 years. Both bull and heifer calves were tested, and each year the performance test ran from the 1st week of May (average age of 233 days) until the 1st week of October. Carcass lean content was predicted from body weight and ultrasonic backfat depth, and lean gain was calculated from the product of live-weight gain and predicted carcass lean content. The LGR line was superior to the control (C) line for live-weight gain on test, lean gain on test and lean gain from birth until the end of test. The LFCR line performed similarly to the C line for live-weight gain on test and lean gain on test, but was inferior for total lean gain. For lean gain on test, the proportional differences between the lines were similar to those predicted from parental breeding values for LGR, but they were smaller for total lean gain. The lines did not differ significantly for either fat depth or predicted carcass lean content.Heritabilities were high for all growth traits, e.g. 0·52 (s.e. 0·17), 0·54 (s.e. 0·17) and 0·59 (s.e. 0·17) for live-weight gain on test, lean gain on test and total lean gain, but lower for fat depth and carcass lean content, 0·25 (s.e. 0·17) and 0·14 (s.e. 0·16), respectively. Genetic correlations with LGR, measured on a concentrate diet, were 0·57 for lean gain on test and 0·56 for total lean gain. If only males were considered, these correlations rose to 0·80 and 0·70, respectively. Coheritabilities between the two environments for lean growth were close to 0·3. It is concluded that although there is some evidence for genotype × environment and genotype × sex interactions, selection for lean growth on a concentrate regimen will still be effective in improving grassland performance.

2001 ◽  
Vol 72 (3) ◽  
pp. 449-456 ◽  
Author(s):  
A. Albera ◽  
R. Mantovani ◽  
G. Bittante ◽  
A. F. Groen ◽  
P. Carnier

AbstractEstimates of genetic parameters for beef production traits were obtained for Piemontese cattle. Data were from 988 young bulls station-tested from 1989 till 1998. Bulls entered the station at 6 to 8 weeks of age and, after an adaptation period of 3 months, were tested for growth, live fleshiness and bone thinness. Length of test was 196 days. Growth traits considered were gain at farm, gain during the adaptation period, gain on test and total gain at the station. Six different fleshiness traits and bone thinness were scored on live animals at the end of the test using a linear system. Live evaluations of fleshiness were adjusted for the weight at scoring in order to provide an assessment of conformation independent of body size. Genetic parameters were estimated using animal models. Heritability of live-weight gain ranged from 0·20 in the adaptation period to 0·60 for total gain at the station. Genetic correlations between gains at station in different periods were high (from 0·63 to 0·97). Residual correlation between gain during the adaptation period and gain during test was negative, probably due to the occurrence of compensatory growth of the animals.Live fleshiness traits and bone thinness were of moderate to high heritability (from 0·34 to 0·55) and highly correlated indicating that heavy muscled bulls also have thin bones. Accuracy of breeding values and therefore response to selection were improved by multiple trait analysis of the live fleshiness traits and bone thinness. Overall weight gain at the station had a moderate negative genetic correlation with all live fleshiness traits and bone thinness (from –0·11 to –0·39).


1996 ◽  
Vol 63 (2) ◽  
pp. 235-241 ◽  
Author(s):  
J. C. Kerr ◽  
N. D. Cameron

AbstractThe responses in traits measured at the start of the mating period and at farrowing were examined after seven generations of divergent selection for daily food intake (DFI), lean food conversion (LFC), lean growth rate (LGA) on ad-\ibitum feeding and lean growth on scale feeding (LGS). Weight and backfat depth at mating were measured on 330 gilts and 74 boars, which were selected on the basis of performance test traits. Farrowing information was available on 259 gilts. At the start of the mating period, gilts selected for high DFI, LGA or LGS had similar live weights (135, 137 and 137 (s.e.d. 4·5) kg) but different backfat depths (20·3, 14·0 and 11·3 (s.e.d. 1·3) mm) while the corresponding low lines had different live weights (129, 117 and 124 kg), but similar backfat depths (17·5, 17·8 and 17·8 mm). Gilts selected for high LFC had lower mean live weight and backfat depth (114 kg and 10·7 mm) than gilts in the other selection lines. Conception rates of gilts selected for low DFI or high LGS were similar (0·62 and 0·64, s.e.d. 0·12) and lower than for the alternative selection strategies (0-78), but the low DFI gilts were significantly older at farrowing than gilts selected for high LGS (424 v. 408 (s.e.d. 5·5) days). Responses in live weight, backfat depth, age at mating and particular reproduction traits were selection strategy dependent, such that identification of relationships between growth and reproduction traits will require measurement of additional growth traits at an earlier age than in the current study


1973 ◽  
Vol 16 (2) ◽  
pp. 173-177 ◽  
Author(s):  
A. R. Renton ◽  
T. J. Forbes

SUMMARYAn experiment was carried out in which a cereal supplement was given to beef cattle, either in suspension in water or as a dry supplement. There were no significant differences between treatments in live-weight gain, food intake or food conversion ratios. Although there was a tendency for the digestibility coefficients of all constituents to be lower on the diet containing the liquid supplement, the differences were not statistically significant. It is concluded that giving a supplement in suspension has no adverse effect on the utilization of the overall diet and could facilitate mechanization of the feeding operation.


2006 ◽  
Vol 82 (5) ◽  
pp. 683-689 ◽  
Author(s):  
G. D. Rosen

AbstractThis exploratory holo-analysis of the efficacy of Bio-Mos®, (BM), an outer cell wall derivative of a strain of Saccharomyces cerevisiae, is part of an empirical modelling research programme comparing the efficacies of potential replacements for veterinary prescription-free pronutrient antibiotics in pig production. The data resource was mined from 128 saccharide publications of which 31/97 on BM (1997 to 2003) provided 69 negatively controlled start-to-finish tests from 10 countries (USA 71%) using 3778 pigs(30·5 per treatment). Respective food intake, live-weight gain and food conversion responses of 0·0075 kg/day (0·99%), 0·0145 kg/day (3·58%) and −0·0526 (3·07%) have coefficients of variation of 511, 163 and 229% and beneficial gain and conversion frequencies of 73 and 68%, 54% jointly. Holo-analytical multiple regression models of BM food intake, live-weight gain and food conversion effects using conventional and less stringent probabilities contain significant independent variables for negative control performances, dosage, discontinuous dosage, test duration, year of test, non-USA test, male, grower-finisher, slatted floor, processed food, antibacterial foods, animal protein food, main vegetable protein not soya bean, added oil/fat food and factorial data, which account for 11 to 68% of variations in response. The models quantify differences in research and praxis and indicate areas for future modelling research on BM dose-response relations, effects of ration ingredient and nutrient contents, other saccharide efficacy comparisons, including lactose, and BM comparisons and interactions with other proposed antibiotic replacements.


1985 ◽  
Vol 41 (2) ◽  
pp. 207-217 ◽  
Author(s):  
I. D. Johnsson ◽  
I. C. Hart ◽  
B. W. Butler-Hogg

ABSTRACTIn crossbred female lambs given a concentrate diet ad libitum between 8 and 20 weeks of age, daily subcutaneous injections of 0·1 mg bovine pituitary growth hormone (GH) per kg live weight increased daily live-weight gain (347 v. 284 g/day; P < 0·01; no. = 8), food conversion efficiency (3·94 v. 4·49 kg dry matter per kg gain; P < 0·01) and greasy fleece weight (1·49 v. 0·99 kg; P < 0·001). The increase (4·8 kg) in final live weight was due primarily to an increase in the non-carcass components of the body (3·5 kg), with little effect on carcass weight (1·3 kg). However, bovine GH treatment markedly increased the weights of lean tissue (11·4 v. 9·2 kg; P < 0·001) and bone (2·8 v. 2·4 kg; P < 0·001) and moderately reduced the weight of fat (7·0 v. 8·0 kg; P < 0·10) in the carcass. The bovine GH treatment raised plasma concentrations of immunoreactive GH within the physiological range for about 16 h each day and significantly increased mean plasma concentrations of insulin and prolactin. Daily injection of 1 mg bromocriptine had no effect on daily live-weight gain, food conversion efficiency or carcass composition. This treatment markedly reduced plasma concentrations of prolactin but also significantly reduced insulin concentrations. When given in combination with bovine GH, bromocriptine reduced the GH-induced stimulation of insulin concentration and tended to decrease the effects of GH on food conversion efficiency and growth. This interaction was significant only for the effects on greasy fleece and skin weights (P < 0·01).


1970 ◽  
Vol 12 (4) ◽  
pp. 543-549 ◽  
Author(s):  
W. Rutter

SUMMARY1. Seventy-two Blackface ewes with 96 Greyface (Border Leicester ♂ × Blackface ♀) lambs were allocated to three groups. Twenty-four ewes with 32 suckling lambs were set-stocked on 2·4 hectares (ha) of grass (A); 32 lambs were weaned and set-stocked on 2·4 ha of grass (B) and 32 lambs were weaned, housed and given concentrates (C). Beef cows with calves were used to control the grass in the two grazing groups.2. The average initial live weight of the lambs was 18 kg. Treatments had a significant effect on performance, the live-weight gains per lamb over the initial 35 days being 11·2, 9·1 and 5·9 kg for groups A, B and C respectively. The total gains over 70 days, when the suckled lambs (A) were weaned, were 17·6, 15·5 and 14·3 kg.3. The total live-weight gain per ha from lambs and calves over 88 days was higher on treatment B than on treatment A. The lambs weaned on to grass took 9 days longer than the suckled lambs to reach a slaughter weight of 42 kg and had significantly poorer killing-out percentages.4.The lambs given concentrates had an overall food conversion efficiency of 4·89 kg concentrates per kg live-weight gain.


1994 ◽  
Vol 59 (2) ◽  
pp. 281-291 ◽  
Author(s):  
N. D. Cameron ◽  
M. K. Curran

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.


1996 ◽  
Vol 63 (1) ◽  
pp. 65-71 ◽  
Author(s):  
L. D. Tregaskes ◽  
P. J. Broadbent ◽  
J. S. M. Hutchinson ◽  
J. A. Roden ◽  
D. F. Dolman

AbstractPuberty during performance test and the effect of reproductive maturity and performance on test on superovulatory response were investigated using Simmental heifers.Three generations of Simmental heifers (no. = 110) were performance tested for beef characteristics between 23 and 49 weeks of age over 3 years successively. Embryo recoveries were performed at 52 and 61 weeks of age following the end of the performance test. The onset of puberty was observed in 26 of 30 (87%) heifers in the 3rd year. The mean age at puberty was 284·7 (s.e. 6·63) days. Age at puberty was not significantly related to daily live-weight gain (1·5 (s.e. 0·02) kg) up to the onset of puberty. Heifers experienced zero to six oestrous cycles before initiation of the first superovulatory treatments. There was a non-significant tendency (P > 0·05) for heifers that were not cyclic to produce the highest yields of viable and grade 1 embryos at the first embryo recovery.Performance test characteristics recorded were: total food intake (1604·0 (s.e. 13·2) kg), total energy intake (1852·0 (s.e. 169·0) MJ metabolizable energy) and live-weight gain (263·9 (s.e. 2·2) kg) during test; live weight (486·5 (s.e. 31·5) kg), backfat depth (5·6 (s.e. 15) mm) and muscle score (9·6 (s.e. 0·10) units) at the end of test and estimated breeding value for the selection index (+£7·00 (s.e. 0·76)). These were used as independent variables in general linear models to study their relationship with various measures of superovulatory response. Recovery rate of ova and embryos; and the yields of viable and grade 1 embryos were not related to any aspects of performance on test.In conclusion, superovulation and embryo recovery were affected by reproductive maturity at the time of gonadotropin treatment and these procedures may be more effective in juvenile heifers before the establishment of cyclicity. Embryo production from 12- to 15-month-old Simmental heifers following a beef performance test was not related to their performance on test.


1983 ◽  
Vol 37 (1) ◽  
pp. 137-140 ◽  
Author(s):  
J. A. Woolliams ◽  
G. Wiener

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.


1982 ◽  
Vol 34 (3) ◽  
pp. 351-353
Author(s):  
Jean M. Bass ◽  
G. Fishwick ◽  
J. J. Parkins

ABSTRACTGroups of Hereford-cross steers weighing 283 kg were given 0·6 kg dry matter hay per head per day, and bruised barley supplemented with 40 g of a fully soluble liquid product per kg, containing urea, minerals and vitamins, ad libitum. Half the animals received 10 g limestone per kg diet as an additional supplement. Over a 105-day period the food intake of the limestone-supplemented animals was 0·20 higher than that of unsupplemented animals. The resultant daily live-weight gain was 1·22 kg compared with 0·92 kg for the animals receiving the diet containing no additional limestone. Food conversion ratios (kg/kg live-weight gain) were improved by limestone supplementation from 6·84 to 6·19. Limestone inclusion did not appear to influence the low concentrations of starch (ca. 15 g/kg) present in the faecal dry matter but there was a small significant difference in faecal pH.


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