Effect Of Breed Type Research Articles

Effects of breed type and supplementation during grazing on carcass traits and meat quality of bulls fattened on improved savannah

Seventy-one bulls representing six breed types: Brahman (BR), F1-Romosinuano (F1ROMO), F1-Limousin (F1LIMO), F1-Angus (F1ANG), F1-Gelbvieh (F1GELB) and ¾ Bos taurus (BT) were used to study the effect of breed type and supplementation on carcass traits and meat quality. Slaughter weight endpoint was at approximately 500 kg. In the non-supplemented group, carcasses of F1ANG and BR surpassed the 56% dressing value, whereas those from F1ROMO, F1LIMO and BT dressed less than 56%. However, F1ROMO and BT groups improved their carcass dressing in two percentage points approximately ( P < 0.05), with supplementation. Carcass weight was only affected by supplementation treatments ( P < 0.05). At slaughter, the supplemented group dressed higher (56.1%) and produced heavier, less mature, better shaped carcasses than the control group. F1 GELB and F1LIMO showed larger (> 68 cm 2) longissimus muscle area (LMA) whereas F1ANG and BR carcasses had better external fat finishing scores and thicker 12th-rib fat thickness (< 1.3 mm). Breed types significantly differed in the yield of most-valuable boneless cuts. Carcasses from supplemented bulls yielded 0.8% more trimmed fat and 1.5% less total retail product. The supplementation × breed type interaction was significant for Warner–Bratzler shear force (WBSF) and overall tenderness. Steaks from BR, F1GELB and BT resulted with higher WBSF values and lower scores for overall tenderness when animals were supplemented ( P < 0.05) whereas the highest tenderness score and lowest WBSF value were obtained by non-supplemented BT bulls. The small differences found between BR and crossbred types allows for describing a similar carcass/beef quality performance under the present grazing conditions. Supplementation on pasture, as designed herein, proved to be a useful practice to improve carcass dressing and overall carcass finish but had detrimental effects on bull meat quality. Other management strategies such as castration, and (or) implants, combined with alternate fattening regimes on tropical savannahs, must be designed to improve meat quality of Zebu-influenced bulls.

Effect of breed type, housing and feeding system on performance of growing pigs managed under organic conditions

AbstractBACKGROUND: There is a need for information on the performance and carcass quality of pigs under different organic management systems. This study compared Duroc‐sired progeny from three maternal breed types when kept either at pasture or in housing with an outdoor run and offered ad libitum concentrate either alone or with fodder beet or grass/clover silage as additional forage.RESULTS: Liveweight gain, feed intake and the proportion of forages consumed did not differ between genotypes. Carcass fatness of progeny was lowest for a ‘modern’ genotype (Camborough 12) and highest for a ‘traditional’ purebred genotype (Saddleback), with a ‘crossbred traditional’ genotype (Saddleback × Duroc) being intermediate (11.4, 14.3 and 13.4 mm P2 respectively, standard error of mean (SEM) 0.27, P &lt; 0.001). With a cereal‐based concentrate available ad libitum, intake of forages was low (&lt;2% of dry matter intake). Although growth rate did not differ between housing systems, daily feed intake was greater at pasture (2.47 vs 2.22 kg meal equivalent, SEM 0.05, P &lt; 0.001), giving poorer feed efficiency (P &lt; 0.01). Pastured animals consumed less additional forage and had a higher killing‐out % but similar carcass fatness.CONCLUSION: For organic pig production to be financially sustainable, disadvantages arising from the genotype and/or rearing system chosen need to be offset by a market premium for the pigs produced. Copyright © 2007 Society of Chemical Industry

Gestation length in first calving Aberdeen Angus x Limousin and Limousin x Aberdeen Angus heifers mated using a synchronised artificial insemination programme

Recent changes to beef production subsidy schemes in the UK has focussed attention on the fertility and reproductive output of suckler beef systems in an attempt to ensure future financial sustainability. Adoption of modern cattle breeding technologies may be more common in the future than they have been in the past as a result of this renewed focus on commercial profitability rather than subsidy reliance. However, relatively little information is available on the biological parameters encountered when modern breeding approaches are employed within commercial crossbred suckler beef management systems in the UK. Previous work (Penny, 2005) has detailed the development of either a triple or double synchronised artificial insemination (AI) programme suitable for use with both multiparous suckler cows and first calving heifers managed as a commercial spring calving suckler herd. The objective of the current report is to detail the effects of breed type and calf sex on average gestation length (GL) in first calving crossbred suckler replacement heifers when mated using a synchronised AI programme.

Evaluation of tropical forage legumes ( Medicago sativa, Dolichos lablab, Leucaena leucocephala and Desmanthus bicornutus) for growing goats

A 56-day feeding trial was conducted to evaluate forage legumes ( Medicago sativa, Dolichos lablab, Leucaena leucocephala and Desmanthus bicornutus) as protein supplements to a sudangrass ( Sorghum bicolor) diet based on growth and feed performance of growing goats. Twenty-four castrated kids were used in the experiment with an average initial age of 135 days and body weight of 18.7 kg. Kids were Boer × Spanish crossbreds. Four dietary treatments were composed of sudangrass (60% of diet offered) supplemented with one of four forage legumes (40% of diet offered) and corn (0.2 kg/day). A split-plot design was employed with diet as the main plot, pens as experimental units (consisting of three pens per diet as replicates) and goats as samples (two goats per pen). Fixed effects of breed type, litter size born, parity of dam and initial age of kid as a linear covariate were added to the model for growth traits. All forage legumes had over 20% crude protein (CP). Final body weight was not affected by diet ( P > 0.05). Average daily gain (ADG) tended ( P < 0.10) to be more rapid for goats fed leucaena compared to desmanthus (least squares means of 93.9 and 60.9 g/day, respectively). Voluntary daily feed intakes of sudangrass and alfalfa were higher by 22 and 33 g ( P < 0.01 and <0.001) per goat for pens receiving alfalfa with sudangrass compared to combined mean intakes of pens fed experimental forage legumes. Intake of leucaena compared to desmanthus forage was higher by 97 g/day ( P < 0.001), demonstrating relatively poorer acceptability of desmanthus. Also, goats fed leucaena had better ( P < 0.05) gain efficiency (ADG/total feed intake) compared to goats fed desmanthus. Experimental results suggest that L. leucocephala had more potential for feeding growing goats in tropical regions compared to the other forage legumes evaluated.

Effects of two dried forages, and a choice between them, on intake, growth and carcass composition in lambs of two breeds and their cross

AbstractThe effects of forage type, breed type and sex on lamb growth and carcass composition, and their changes throughout growth, were measured. The three breed types were Scottish Blackface (no. = 31), Suffolk (no. = 28) and their reciprocal cross (no. = 30). The lambs were given ad libitum a pelleted ryegrass alone, pelleted lucerne alone or a choice of both. Each lamb was scanned using X-ray computed tomography to measure the weights of fat, lean and bone in the carcass at three proportions of mature body weight (0·30, 0·45 and 0·65). Live weights and food intake data were recorded weekly. Average daily gains in live weight and carcass tissues, food intake and efficiency were calculated for each lamb between degrees of maturity. Relationships between weight and food intake were investigated using a Spillman function.Breed type had no effect on fat or lean proportion in the carcass but Scottish Blackface lambs had 1·04 times the carcass bone proportions of the Suffolk or crossbred lambs. Diet had no effect on carcass tissue proportions. The effect of sex on carcass composition changed with stage of maturity. Breed type and sex effects on intakes and gains in live weight and tissue weights were related to mature size differences. Scaling by (mature size)0·73did not fully remove these differences. There were no effects of breed type, sex or diet on efficiency. Lambs on ryegrass had lower intakes (0·878 as great) and slower growth (0·851 as fast) than those on lucerne or the choice treatment. The mean proportion of ryegrass in the choice diet was 0·366 (s.e. 0·0273); it increased slightly with time. There was no breed type by diet interaction for any of the variables examined. The Spillman function described growth well and showed that there were no effects of breed type, diet or sex on efficiency.

An investigation of the efficiency of nutrient utilization for milk production by Holstein and Norwegian breeds of dairy cattle

Holstein-Friesian cattle are the predominant breed of dairy cattle in Northern Ireland. Breeding programmes for the Holstein Friesian have focused on improved milk production with little emphasis on functional traits such as fertility or disease resistance. In contrast Norwegian dairy cattle have been bred via a multi-trait selection procedure and there is evidence that problems associated with disease and fertility have tended to decrease in recent years. It is important, however, to investigate possible differences in efficiency of food use and partitioning of nutrients between the two breeds which may offset the potential advantages of improvements in secondary characteristics. Consequently, the objectives of this experiment were firstly to investigate the effects of breed type on the efficiency of utilization and partitioning of nutrients for milk production and secondly to investigate if there are differences in the energy requirement for maintenance and the efficiency of utilization of ME for lactation (kl) between the two breeds.

Effect of breed type, sex, method of rearing, winter nutrition and subsequent grazing treatment on lifetime performance and carcass composition in a 20-month beef system: carcass characteristics

AbstractIn a lifetime study of spring-born cattle in a 20-month beef system the effects of production factors on carcass characteristics were examined using 302 serially slaughtered animals born in three consecutive years. A multifactorial design was used with three animal factors — maturity (early maturing Hereford crosses v. late maturing Charolais crosses), sex (heifer v. steer) and method of rearing (suckled calves v. bucket-reared calves). After an initial rearing period, feeding treatments were imposed during the subsequent winter period, followed by the imposition of two sward heights (low 6 to 8 cm and high 8 to 10 cm) during the subsequent grazing season. An initial representative group of 16 cattle was slaughtered at the start of the grazing season and most of the remaining cattle were subsequently slaughtered off grass at three randomly allocated slaughter times, on average 67, 110 and 154 days post turn-out. Interactions between the main production factors were not significant with the exception of slaughter date with winter feeding levels for fat in rib joint and weight of saleable meat, and slaughter date and sex for live weight, carcass weight and weight of saleable meat. Breed type, sex and method of rearing affected the weight of saleable meat off grass by 14·7, 14·8 and 5·6 kg respectively. The influence of the winter feeding treatments on the weight of saleable meat was small by the time the final group were slaughtered. Sward height had a transient effect on weight, condition and carcass composition, the effects becoming less evident as the grazing season progressed. The effect of delaying slaughter had the largest and most significant influence on carcass composition of all the production factors studied, although changes in body composition between slaughter dates were relatively slow.

Effect of breed type, lactation and nutrition on the calving probability of cattle grazing subtropical pastures in Australia

The relationship between liveweight at mating and calving probability was examined in cattle grazing subtropical pastures in a 4 year study. The aim was to establish whether breed type, lactation, protein meal supplements, and/or pasture quality affected the relationship. Cows (n=242) of Hereford (H), Brahman (B) and Brahman×Hereford (BH) breed types were selected as maiden heifers, 20–;27 months of age, and grazed pastures of low digestibility (D), (0·45–0·62) and medium (D, 0·47–0·67) quality which are typical of subtropical grassland areas. The maiden heifers were supplemented with cottonseed meal (D, 0·67, 61 g nitrogen/kg) at 0, 750 or 1500 g/day for 130 days and mated during 90 days in the first year of the study and as cows in the following three years. There were 633 mating records of cows collected during the study.A generalized additive model was used to describe the relationship between calving probability and mating liveweight. There was no relationship between mating liveweight and calving probability when the model included the main factors. At the mean herd mating liveweight of 430 kg the calving probability (predicted mean±S.E.) of B cows (0·59±0·034) was less than that of H (0·74±0·029) or BH cows (0·81±0·026). There were significant reductions in calving probability with lactation and from medium to low pasture quality. Calving probability was not increased significantly in BH cows by supplementation but was for B and H cows. On low quality pastures, lactation reduced predicted calving probability from 0·77 to 0·54 for non-supplemented H cows and from 0·61 to 0·35 for non-supplemented B cows. The reductions were smaller in H and B cows when supplemented at 1500 g/day. On medium quality pastures the effect of lactation and supplementation on the calving probability of cows was less than for those grazing low quality pastures.

Survival, body weights, feed efficiency, and carcass traits of 7/8 White Composite and 1/8 Duroc, 1/8 Meishan, 1/8 Fengjing, or 1/8 Minzhu pigs.

Pigs were the progeny of White Composite boars mated to gilts that were either 1/4 Duroc, 1/4 Meishan, 1/4 Fengjing, or 1/4 Minzhu and the remainder 3/4 White Composite. One-eighth Meishan and 1/8 Fengjing pigs averaged approximately .5 more nipples than 1/8 Duroc pigs and .2 more nipples than 1/8 Minzhu pigs (P < .05), respectively. Duroc, Meishan, and Minzhu crosses did not differ (P > .05) for survival at birth or at 14 and 28 d. Fengjing crosses had a lower survival rate (P < .05) at all three ages than Duroc and Meishan crosses. Duroc crosses were heavier (P < .05) than Chinese crosses at birth. At 56 d, Duroc and Meishan crosses did not differ (P > .05) for BW, but both were heavier (P < .05) than Minzhu crosses. Body weight at 70 d did not differ significantly (P > .05) among breed types. Duroc crosses were heavier (P < .05) than any of the Chinese crosses at 98, 126, and 154 d of age. At 154 d, Fengjing crosses were lighter (P < .05) than Meishan or Minzhu crosses. The effect of breed type was not detected for average probe backfat thickness of gilts at 99.7 kg. Duroc crosses consumed the most feed, and Fengjing crosses consumed the least during each interval and during the total period (P < .05). Feed consumption of Meishan and Minzhu crosses was intermediate to and significantly (P < .05) different from that of Duroc and Fengjing crosses. At 184 d of age, breed types did not differ (P > .16) for measures of carcass fat thickness, marbling score, color score, and firmness score. At 184 d of age, weights of all carcass cuts were heavier (P < .05) for Duroc than for Chinese crosses with the exception of untrimmed loin weight of Minzhu crosses. There were few significant differences among breed types when carcass traits were compared at a constant carcass weight, although Duroc crosses generally were superior. Relative to similar Duroc crosses, these results suggest that 1/8 Chinese pigs would grow less rapidly (P < .05) and produce less weight of trimmed lean cuts at a constant carcass weight.

Comparison of Sumatra sheep and three hair sheep crossbreds II. Reproductive performance of F 1 ewes

A total of 196 young Sumatra (S) ewes and F 1 crosses of S with Java Fat-tail (E1), Virgin Island (H1) and Barbados Blackbelly (B1) were mated with rams of their same breed type. The ewes were first exposed to the ram at 10 or 13 months of age, and reproductive performance was monitored until each ewe had reared two litters. Data from a total of 363 lambings and 563 lambs were included in the analysis. Mean ages at first and second lambings were 516 and 733 days. Litter size at birth ranged from 1 to 5 lambs with a mean of 1.55, and pre-weaning mortality (to 3 months) was 11.7%. There were no significant effects of breed type on age at lambing, lambing interval, litter size or mortality. The mean birth weights of lambs born to the S, E1, H1 and B1 ewes were 1.45, 1.62, 2.03 and 2.10 kg, respectively. Weaning weights averaged 8.5, 9.2, 11.7 and 12.1 kg for the four breed types. The differences among breed types were significant ( P < 0.001) except for H1 and B1 which were similar. Litter size affected ( P < 0.001) birth weights, weaning weights and pre-weaning mortality. A dam productivity index (DPI) for each ewe was calculated from the total weight of lamb weaned at the first two lambings divided by a measure of age. DPI was affected ( P < 0.001) by breed type, and averaged 16.0, 18.1, 21.5 and 24.2 kg for the S, E1, H1 and B1 genotypes, respectively. Average weights of ewes at second lambing were 22.0, 24.4, 27.2 and 28.1 kg for the four genotypes, respectively. Thus, productivity expressed in terms of weight of lamb weaned per unit body weight of ewe was 0.73, 0.74, 0.79 and 0.86 for the S, E1, H1 and B1 genotypes, showing that the hair sheep crossbreds were more productive. DPI was slightly higher for ewes mated at 10 months of age than at 13 months, indicating no advantage in delaying first mating.

Effect of breed type, sex, method of rearing and winter nutrition on lifetime performance and carcass composition in a 20-month beef system: grazing performance

AbstractIn a lifetime study of spring born cattle managed in a 20-month beef system, four feeding treatments were imposed during the 5-month winter period and two grass heights (low 6 to 8 cm, high 8 to 10 cm) during the subsequent grazing period. Three slaughter weights were imposed over the grazing period, early, mid and late, at an average of 67,110 and 154 days post turn-out. A multi-factorial design was used with three animal factors — maturity (early maturing Hereford crosses v. late maturing Charolais crosses), sex (heifer v. steer) and method of rearing (suckled calves v. bucket-reared calves). There were significant differences in growth rate for both sex and maturity (P &lt; 0·001) and a highly significant negative effect of winter food level on summer growth rate (P &lt; 0·001), the growth rate of food treatment 4 being proportionately 0·61 of that treatment 1.Sward height significantly influenced summer growth rate (P &lt; 0·001) but showed no interaction with winter food level in any of the three grazing periods. Growth rates increased over the summer but differences between winter food treatments decreased with daily gains for food treatment 4 being proportionately 0·44, 0·81 and 0·84 of food treatment 1 as the grazing season progressed.Eliminating winter feeding treatment as a factor and including condition score at turn-out as a co-variate improved the variation explained and reduced differences in growth rate for the main effects with only the main effect of grass height remaining significant. This suggests that the condition of animals at turn-out in conjunction with the subsequent grazing sward height provides a simple practical guide to subsequent animal performance.

Effects of breed type and accelerated fat removal on subprimal yields and carcass values

Nine Brown Swiss and nine English crossbred steers representing the industry standard were slaughtered to determine the effects of cattle type and hot fat removal on subprimal yields and carcass value. After dressing, cod fat, kidney, pelvic, and heart fat (KPHF), and subcutaneous fat thicker than .6 cm was removed from the right side of each carcass (HFT). The left side was not hot-fat trimmed (NFT). Both sides were fabricated into subprimal cuts with no more than .6 cm of subcutaneous fat. Carcass side values were adjusted to a 300-kg chilled carcass weight basis. All comparisons were made for the carcasses using a USDA Select quality grade end point. English crossbred steer carcasses had more (P < .05) subcutaneous fat on the loin and chuck and more (P < .05) total hot fat trim, when KPHF was not included, than Brown Swiss steers (P < .05). Brown Swiss steers had more (P < .05) KPHF. Hot-fat trimmed sides had higher (P < .05) percentage yields from the chuck, brisket, foreshank, rib, plate, round primal cuts, and most of the subprimal cuts than NFT sides, but the primal loin percentage was higher (P < .05) in the NFT sides. The total subprimal cuts yield was approximately 5% higher for the HFT sides than for the NFT sides, and the total fat trim during fabrication was more than 6% less. When the value of the sides was calculated from unadjusted weights, the NFT sides were approximately $26.50 more valuable than the HFT sides.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of calf genotype on colostral immunoglobulins in Bos taurus and Bos indicus cows and serum immunoglobulins in their calves.

Purebred Bos indicus calves are documented to have lower survival rates than Bos taurus calves. Thus, this study was designed to investigate the possibility that this decreased survival rate may be attributed to dam colostral immunoglobulin (Ig) concentrations and subsequent calf serum Ig concentrations. The specific objective was to determine the effect of breed type of calf on colostrum production, immunoglobulin concentrations in colostrum and calf serum, and availability and absorption efficiency of Ig. Brahman (B) and Angus (A) cattle were reciprocally mated to produce calves of the following types: A x A (n = 8), A x B (n = 9), B x B (n = 11), and B x A (n = 11). At birth, calves were separated from their dams and a blood sample was collected before feeding pooled colostrum (30 mL/kg birth weight) at 1 and 6 h of age. From 6 to 12 h of age, each calf was placed in a box that allowed interaction with the dam but prevented suckling. At 12 h of age, each calf was fed its dam's colostrum and placed with the dam. Additional blood samples were collected at 12, 24, and 48 h after birth. Serum and colostrum samples were analyzed for IgG, IgG1, IgG2, IgM, and IgA using single radial immunodiffusion (RID) assay techniques. The cows were hand-milked after induction of milk letdown with oxytocin at 1 and 12 h after calving. Colostrum volume was recorded, and samples were collected. Brahman cows produced more (P < .001) colostrum at 1 and 12 h than A cows. Total Ig concentrations were obtained by summing IgG, IgG1, IgG2, IgM, and IgA concentrations. Total Ig (P < .02), IgG (P < .005), and IgA (P < .01) concentrations in colostrum were greater in cows producing crossbred calves. Total Ig (P < .006), IgG (P < .02), IgG1 (P < .004), and IgG2 (P < .02) available in colostrum were affected by B x B and A x B breed types of calf. Brahman cows had more Ig available at 1 and 12 h than A cows due to increased production of colostrum. Breed type influenced colostral Ig in cattle. Serum concentrations of total Ig, IgG, IgG1, IgG2, IgM, and IgA in the calf and efficiency of absorption at 6 and 12 h were not affected by breed type, sex of calf, or any interaction.

Rotation crosses and inter se matings with Angus and Hereford cattle for five generations

A total of 3768 calves and 4950 cow mating-years were involved in a study of heterosis retention. Crosses included first and subsequent inter-crosses between Angus and Hereford breeds as far as the fifth calf generation (F1, F2,…F5), back crosses (B1) using both F1 sires and F1 dams, and rotation crosses as far as the fifth calf generation (R2, R3, R4 and R5). Records collected were calf traits to the yearling stage, cow reproduction and maternal traits, and steer carcass data. Effects were estimated for 27 breed types for calves and 23 for cows. Breed type effects were then replaced by multiple regression coefficients for genetic effects including: an average individual (Angus) breed effect (g I), average maternal (g M) and average grandmaternal (g MG) breed effects, individual (d I), maternal (d M) and paternal (d P) dominance effects, and epistatic effects. From these, individual (h I) and maternal (h M) heterosis and other parameters were derived. For the Angus breed, g I was generally negative and g M positive for direct calf weights and cow weight; g I was positive for calf weaning weight (WW) as a maternal trait. The Angus breed was superior to the Hereford for net reproduction, productivity (weight of calf weaned per cow mated) and an efficiency ratio (productivity/average cow weight). Relative to the average of the purebreds, the superiorities of F1, F3 to F5, and R4 animals were respectively 2.1, 3.2 and 5.0% for birth weight, 6.5, 3.7 and 7.9% for yearling weight, 6.7, −2.2 and 3.4% for cow weight, 10.3, 0.7 and 11.7% for calf WW as a maternal trait, 7.4, −1.3 and 5.7% for number of calves weaned per cow mated, 19.4, 1.0 and 18.4% for productivity, and 11.2, 2.1 and 14.0% for the efficiency ratio. For calf traits and cow weight, d M and h I were generally significant and positive (except negative for calving date), whilst only h I was generally significant for calf weights as maternal traits. For the reproductive traits, the trends were for h I to be positive, but standard errors were large. For carcass traits, the interbreds and rotation crosses were generally like the heavier, fatter (i.e. Hereford) purebred. Overall, for productivity and the efficiency ratio, the rotation crosses (especially R4) were superior to the purebreds but generally not to the Fls, whilst the interbreds were similar to the purebred average.

Effect of breed type, sex and method of rearing on lifetime performance and carcass composition in a 20-month beef system: effects of winter feeding treatments

AbstractIn the winter feeding phase of a lifetime study of spring-born cattle managed in a 20-month beef system, a total of four feeding treatments were imposed by increasing the level of concentrate supplement offered with ad libitum grass silage. The objective was to achieve a difference in live weight at the end of the winter of about 25 kg between food treatments. A multifactorial design was used with three animal factors — maturity (early maturing Hereford crosses v. late maturing Charolais crosses), sex (heifer v. steer) and method of rearing (suckled calves v. bucket-reared calves).There were no significant differences between breeds but highly significant (P &lt; 0·001) differences for method of rearing and sex. As a consequence live-weight differences at the end of the winter between breed types (18 kg) were less than the difference between the sexes (23 kg) and for method of rearing (25 kg) although all were highly significant. Although suckled animals had significantly lower growth rates they were still significantly fatter at the end of the winter as were heifers and Hereford crosses. Differences in dry-matter intake were reflected in growth rate.Plane of winter nutrition had a highly significant effect (P &lt; 0·001) on live weight and condition score at the end of the winter resulting in increments of about 23 kg and 0·12 units of condition for each level of feeding.Interactions between the main production variables were not significant with the exception of feeding level and method of rearing. Suckled animals showed a significant (Y &lt; 0·001) reduction in winter gain (proportionately 0·85 for that of bucket-reared animals) when offered the same diet. This reduction ranged proportionately between 0·25 and 0·08 for the lowest and highest daily levels of concentrate supplementation respectively. An extra 1 kg concentrates per day was required for suckled animals to achieve similar live-weight gains to bucket-reared animals.

The effect of breed type on beef carcass characteristics and Canadian carcass grade

The carcass traits of 486 steers representing four breed types (British purebred, British crossbred, European crossbred, European purebred) were evaluated. Carcasses from European purebreds and crossbreds were heavier and leaner than those from British purebreds and crossbreds. British purebreds had a higher frequency of small marbling than European purebreds and crossbreds, but there was considerable variation in marbling across all breed types. It was concluded that European purebreds and crossbreds would return a higher market value than British purebreds and crossbreds under current marketing conditions. Key words: Cattle, carcasses, grade, breed

Plasma cholesterol and lipoprotein concentrations in the dog: The effects of age, breed, gender and endocrine disease

ABSTRACTA combined ultracentrifugation and precipitation technique was used to quantify the plasma lipoprotein concentrations of control dogs (n=33) and dogs with diabetes mellitus (n=11), hyper‐adrenocorticism (n=14), hypothyroidism (n=10) and obesity (n=20). In addition, the effect of breed type, age and gender on the lipoprotein phenotype was assessed. Breed type and age were found to have no effect upon cholesterol and lipoprotein concentrations but the high density lipoprotein cholesterol (HDL‐C) concentration was greater in intact females than intact males. Cholesterol concentrations were significantly higher than those of the control group in dogs with diabetes mellitus (P&lt;0·01), hyper‐adrenocorticism (P&lt;0·01) and hypothyroidism (P&lt;0·001). In dogs with diabetes mellitus this was due to increased concentrations of very low density lipoprotein cholesterol (VLDL‐C) (P&lt;0·01) and HDL‐C (P&lt;0·05). The concentrations of low density lipoprotein cholesterol (LDL‐C) (P&lt;0·05) were significantly increased in dogs with hyperadrenocorticism, while in the hypothyroid dogs, VLDL‐C (P&lt;0·05), LDL‐C (P&lt;0·001) and HDL‐C (P&lt;0·05) were significantly higher than the control group. The cholesterol and lipoprotein concentrations in the obese population were not significantly different from control dogs.

Performance of British Saanen, Boer × British Saanen and Anglo-Nubian castrated male kids from 8 weeks to slaughter at 28, 33 or 38 kg live weight

AbstractThe performance of British Saanen, Boer × British Saanen and Anglo-Nubian kids from weaning to slaughter at 28, 33 or 38 kg live weight (LW) was examined in a 3 × 3 factorial experiment. Kids were reared on a concentrate and hay ration, after weaning at 8 weeks of age. Intakes were measured individually. At slaughter, carcasses and body fractions were weighed, left half-carcasses were dissected into muscle, fat and bone, and the carcass and non-carcass fractions were analysed chemically. There ivas no significant effect of breed type on mean daily intakes, but there was a significant breed-type effect on mean daily LW gains in the order British Saanen &gt; Boer × British Saanen &gt; Anglo-Nubian kids. Compared with the pure British Saanen kids, the Anglo-Nubian kids produced heavier carcasses yielding more muscle and less subcutaneous and intermuscular fat at each slaughter weight. By contrast, the Boer × British Saanen carcasses contained proportionately more fat, mainly intermuscular fat, than the British Saanen when slaughtered at 28 or 33 kg LW. When taken on to slaughter at 38 kg LW, the Boer × British Saanen kids showed little further increase in fat deposition at the internal and intermuscular sites compared with the British Saanens, resulting in carcasses with slightly more subcutaneous fat but lower overall carcass fat content.

Straightbred and crossbred weaner steers bred in north-eastern New South Wales and grown on Victorian foodlots and pastures

Weaner steers of 6 breed types were procured from 82 herds from the North Coast of New South Wales and grown in feedlots and on pastures in Victoria over a 3-year period. Growth and carcass traits were compared when adjusted to a common initial liveweight (204 kg), and breed type effects were tested using the between-herd (of origin) mean square as error. Steers comprised Hereford; first-cross Angus x Hereford (A x H); first-cross Brahman x Hereford (B X H); Braford; an outcross A x (B x H); and a backcross H x (B x H). Initial liveweight was significantly and positively correlated with final liveweight, carcass weight, dressing percentage, muscle score, subcutaneous fat depth [except for B x H and A x (B x H)], and eye muscle area [except for H x (B x H)]. There was no significant relationship between initial liveweight and daily gain. Feedlot steers grew faster than pasture steers (1159 v. 741 g/day) and were slaughtered earlier (after 144 v. 268 days) at similar carcass weights (202 kg) and subcutaneous fat depths at the 12-13th rib (6.6 mm). Muscle colour was significantly lighter for the younger feedlot steers, but all other fat and muscle measurements were unaffected by feed type. The A x H and B x H steers had the highest carcass weights (204 and 206 kg, respectively), while Braford and H x (B x H) steers had the lowest (both 199 kg). The A x H steers had the highest muscle score and greatest subcutaneous fat depth (5.6 units and 8.2 mm), while Braford steers ranked lowest for these measures (4.9 units and 5.5 mm) when adjusted to the same initial liveweight. Underlying these differences were significant breed effects on daily gain (range 71 g/day), final liveweight (range 10.8 kg), and dressing percentage (range 1.6%). There was a significant breed type x feed type interaction for muscle colour: on feedlot, A x (B x H) were significantly lighter than Hereford; and on pasture, H x (B x H) and A x H were lighter than B x H and A x (B x H), and Hereford were lighter than B x H. The range in producer effects (origin) on daily gain was 80-124% of the overall mean, with a repeatability of 0.47. Except for fat depth, breed differences were small, but first-cross steers were generally superior to progeny of first-cross cows. This indicates a conflict in the choice of breed type between that which performs best for rowers (first-cross cattle) and that which performs best for North Coast store weaner producers (calves from first-cross dams). There were large differences in growth rate between steers from different producers that could not be attributed to any 1 factor.

Comparison of rabbit breed types for postweaning litter growth, feed efficiency, and survival performance traits

Postweaning data on 643 rabbits from 122 litters representing four breed types, New Zealand White (NZW) and Californian (CAL) purebreds, CAL X NZW (CXN), and Flemish Giant (FG) crossbreds (the latter group was a collection of FG X CAL, FG X Champagne D'Argent [CHA], and 1/2 FG X 1/4 CAL X 1/4 CHA), were gathered over five seasons and compared for growth, feed efficiency, and survival-related performance traits. Evaluation criteria included litter size and weight at weaning (28 d); 28- to 70-d litter feed intake, weight gain, feed efficiency, and mortality rate; and litter and average market weight (70 d). The least squares model included main effects of breed type, season of birth of the litter and parity of dam, litter size at weaning as a linear covariate, and the random error. Breed-type differences were not detected for litter size and weight at weaning and feed efficiency. Purebred NZW and CAL litter trait performances were comparable (P greater than .05). Purebred NZW litters consumed less feed than CXN and FG crosses, gained weight less rapidly than FG crosses, and weighed less per fryer at 70 d than CXN and FG crosses (P less than .05). Feed intake was lower and average market weight was lighter for CAL purebred litters than for CXN and FG crossbred litters (P less than .05). The CXN and FG crossbreds only differed (P less than .05) for average market weight (2,078 vs 2,192 g). Mortality rate was lower (P less than .05) in CXN crossbred litters than in CAL purebred litters.(ABSTRACT TRUNCATED AT 250 WORDS)