scholarly journals Performance of steer progeny of sires differing in genetic potential for fatness and meat yield following post-weaning growth at different rates. 1. Growth and live-animal composition

2009 ◽  
Vol 49 (6) ◽  
pp. 515 ◽  
Author(s):  
J. F. Wilkins ◽  
W. A. McKiernan ◽  
J. Irwin ◽  
B. Orchard ◽  
S. A. Barwick
Keyword(s):  
Body Composition ◽  
Slow Growth ◽  
New South ◽  
Subcutaneous Fat ◽  
Live Animal ◽  
Meat Yield ◽  
Genetic Potential ◽  
South Wales ◽  
The Difference ◽  
Estimated Breeding Values

The present experiment, ‘Regional Combinations’, examined growth, and carcass- and meat-quality traits in the progeny of sires genetically diverse for fatness and meat yield when grown at different rates from weaning to feedlot entry. The present paper is the first of several papers describing results from the New South Wales site, one of four in the project. It reports the effects on growth and body composition of steers during backgrounding and feedlot finishing phases. A total of 43 sires within three carcass-class categories, defined as high potential for meat yield, for marbling or for both traits, was used, based on estimated breeding values for retail beef yield and intramuscular fat. Sires were drawn from Angus, Charolais, Limousin, Black Wagyu and Red Wagyu breeds, providing a range of carcass sire types across the three carcass classes. Matings were by artificial insemination to Hereford dams from a single herd. Steer progeny were grown at conventional (slow: ~0.5 kg/day) or accelerated (fast: ~0.7 kg/day) rates from weaning to feedlot entry weight, targeting group means of 400 kg. Accelerated and conventionally grown groups from successive calvings entered the feedlot at similar entry liveweights at the same time, then having identical management during the 100-day finishing phase before slaughter. Within finishing cohorts, fast backgrounding growth resulted in increased subcutaneous fatness at feedlot entry in steers of all carcass types. Slow growth during backgrounding resulted in faster (compensatory) growth in the feedlot in all classes and sire types. This increased the deposition of fat in slow-backgrounded steers compared with that in fast-backgrounded steers during feedlotting, and thus reduced the difference between the groups in P8 and rib fat at feedlot exit. However, there did appear to be an advantage in the level of compensation in the feedlot in favour of those sire types with a genetic propensity for faster growth. Backgrounding growth rate affected body composition and the rate of weight gain during finishing. Faster growth produced more subcutaneous fat during both backgrounding and finishing. Steer progeny groups clearly showed the expected responses in growth and body composition, on the basis of the genetic potential of their sires.

The impact of selecting for increased ewe fat level on reproduction and its potential to reduce supplementary feeding in a commercial composite flock

2016 ◽  
Vol 56 (4) ◽  
pp. 698 ◽  
Author(s):  
S. F. Walkom ◽  
F. D. Brien ◽  
M. L. Hebart ◽  
W. S. Pitchford
Keyword(s):  
Body Composition ◽  
Body Condition ◽  
New South ◽  
Supplementary Feeding ◽  
South Wales ◽  
Fat Level ◽  
Grazing Systems ◽  
Selection For ◽  
The Difference ◽  
The Impact

In southern Australian grazing systems, energy availability typically exceeds energy requirements. Grazing systems are likely to have higher profitability if ewes can utilise this relatively cheap feed by gaining more condition (muscle and fat) and then mobilising it when feed is expensive. The present paper focusses on the importance of genetic merit for fat on the lifetime productivity of the ewe within a commercial operation. The analysis was carried out on a maternal composite stud flock in Holbrook, New South Wales. Ultrasound fat and muscle depth were measured on 2796 ewes as lambs at post-weaning and as adult ewes, to determine the genetic relationship between young and adult body composition. The hypothesis of the paper is that selection for increased fat at young age will improve body condition of adult ewes, which will lead to improved reproduction and potentially reduced requirements for supplementary feeding. Given that the difference in feed cost between times of abundance and shortage is likely to be larger, the system may become more profitable despite being less efficient (owing to increased feed intake). Our results indicated that selection for scanned post-weaning fat and muscle depth in lambs should lead to increased fat muscle and body condition in the breeding ewe because of strong genetic correlation estimates between the post-weaning and adult traits of 0.68–0.99. The influence of body composition traits on reproduction (number of lambs weaned) within the stud flock was weak. However, it is hypothesised that by genetically increasing post-weaning fat depth in ewes, producers could improve profitability by reducing the demands for supplementary feeding.

Use of products of straw decomposition by N2-fixing (C2H2-reducing) populations of bacteria in three soils from wheat-growing areas

1986 ◽  
Vol 37 (1) ◽  
pp. 1 ◽  
Author(s):  
MM Roper ◽  
DM Halsall
Keyword(s):  
Nitrogenase Activity ◽  
New South ◽  
Carbon Sources ◽  
Clay Content ◽  
Free Living ◽  
Straw Decomposition ◽  
South Wales ◽  
History Of ◽  
Straw Incorporation ◽  
The Difference

The potential for N2 fixation by free-living bacteria using straw as a source of energy was evaluated in three soils (one from Gunnedah and two from Cowra) representative of the wheat belt in New South Wales. All three soils had a history of straw incorporation. The abilities of the respective microbial populations to use a range of carbon sources, including potential products of decomposition of straw, was determined and compared with the size and composition of each population. Neutral to alkaline (pH 7.4) soil of high (51%) clay content from Gunnedah produced higher rates of nitrogenase activity with straw than more acid (pH 5.6) lower (17%) clay containing soil from Cowra (site B). Gunnedah soil also contained a larger population of N2-fixing bacteria which used a broader range of energy sources than soil from either Cowra site B or Cowra site W (pH 5.8, clay content 34%). There was little difference in the composition of the N2-fixing populations in each of the soils except that Azotobacter spp. were absent from the acid Cowra soils. It was concluded that the difference in behaviour of the respective N2-fixing populations was primarily due to the physical characteristics of the soil affecting the numbers and activities of diazotrophic microorganisms. In addition some soil environments failed to support specific organisms.

Nature Conservation in Rangelands: Lessons From Research on Reserve Selection in New South Wales.

1992 ◽  
Vol 14 (2) ◽  
pp. 214 ◽  
Author(s):  
RL Pressey
Keyword(s):  
Conservation Planning ◽  
New South ◽  
Full Range ◽  
New South Wales ◽  
Reserve Selection ◽  
South Wales ◽  
Land Systems ◽  
The Difference ◽  
Selection Of

Information on the features to be protected in a system of conservation reserves is an obvious requirement. The quality of the data base will primarily determine the effectiveness of conservation planning in protecting the full range of natural features in a region. However, the way in which data are used to make decisions on the locations of protected areas is also critical. Rigorous procedures for reserve selection can make the difference between achieving reservation goals or not. Research on reserve selection in New South Wales over recent years has concerned both data bases and procedures for guiding decisions. Reserve planning in many regions is based largely on some form of land classification like vegetation types or land systems. There are good reasons for using such land classes to guide the selection of reserves and to judge their representativeness. Nevertheless, they can have considerable limitations as a basis for protecting all the species in a region. These limitations are reviewed with references to more detailed discussions of particular issues. The paper also reviews a variety of procedures for selecting reserves which have been tested and applied in New South Wales. Some of the recent procedures are conceptually simple but very useful in identifying the requirements of reservation goals and demonstrating the options available to planners for representing particular features. Three principles are proposed which should underpin any attempt at systematic conservation planning.

Predation of Red Kangaroos, Macropus rufus, by the Dingo, Canis familiaris dingo (Blumenbach) in North-Western New South Wales

1981 ◽  
Vol 8 (2) ◽  
pp. 255 ◽  
Author(s):  
NC Shepherd
Keyword(s):  
New South ◽  
New South Wales ◽  
Pathological Finding ◽  
South Wales ◽  
Daily Rate ◽  
Rate Of Increase ◽  
Border Fence ◽  
Selection For ◽  
The Difference ◽  
North Western

Over 7 weeks a group of five dingoes killed 83 red kangaroos within 150 m of a watering point in north-western New South Wales. All except three of these kangaroos were juveniles. Detailed autopsies were performed on 17 of the dead kangaroos: primary predation was the only significant gross pathological finding; the dingoes had eaten portions from about half the kangaroos killed. The daily rate of killing was estimated to be about 0.38 kg prey per kg predator. The rate of killing and the selection for juvenile kangaroos suggested that dingoes could have a direct effect on kangaroo densities by limiting rate of increase. The significance of this finding is discussed with reference to the difference in abundance of kangaroos between the New South Wales and Queensland sides of the border fence.

Seasonal Field Energetics of the Rufous Rat-Kangaroo (Aepyprymnus-Rufescens)

1992 ◽  
Vol 40 (3) ◽  
pp. 279 ◽  
Author(s):  
IR Wallis ◽  
B Green
Keyword(s):  
New South ◽  
Water Flux ◽  
Behavioural Ecology ◽  
Free Living ◽  
Doubly Labelled Water ◽  
South Wales ◽  
Poor Understanding ◽  
Males And Females ◽  
The Mean ◽  
The Difference

Water flux and field metabolic rate (FMR) were measured by the doubly labelled water (DLW) method in free-living male and female rufous rat-kangaroos Aepyprymnus rufescens near Drake in northern New South Wales. The mean FMR of 499 kJ kg-1 day-1 was similar in winter and summer even though the difference in mean minimum temperatures between the two seasons was 20-degrees-C. Furthermore, we did not find any differences in FMR between males and females even though several females carried large pouch young or had young-at-foot. A poor understanding of the diet and the behavioural ecology of A. rufescens makes ft difficult to explain the similarities between sexes and seasons.

The Inpact of River Discharge on Distribution and Production of the School Prawn Metapenaeus macleayi (Haswell) (Crustacea : Penaeidae) in the Clarence River Region, Northern New South Wales

1978 ◽  
Vol 29 (3) ◽  
pp. 311 ◽  
Author(s):  
JP Glaister
Keyword(s):  
River Discharge ◽  
Ecological Study ◽  
New South ◽  
Total Production ◽  
Catch Per Unit Effort ◽  
Lunar Periodicity ◽  
South Wales ◽  
River Region ◽  
Schooling Behaviour ◽  
The Difference

Relationships between river discharge and production (catch) of the school prawn M. macleayi were examined as part of an ecological study of this species in the Clarence River region. Schooling behaviour of juvenile M. macleayi exhibited a lunar periodicity and mean daily abundance peaked 5 days after full moon. This was followed 7 days later by a peak in mean daily abundance of emigrating juvenile M. macleayi. Fluctuations in the magnitude of the oceanic component of the total annual catch were found to determine the difference between high and low production seasons. During the period examined there was a direct relationship between Clarence River discharge and the oceanic component of total production of M. macleayi, for various time periods. The absence of a persistent trend in total annual production and annual catch per unit effort of M. macleayi in the Clarence River region suggests that the stock has not been overfished. Common peaks in mean monthly oceanic production of M. macleayi off the Clarence, Evans and Richmond Rivers suggest a common enhancement of the seasonal emigration of M. macleayi from the three estuaries in November due to increased river discharges. Successive troughs and peaks in mean monthly oceanic production suggest a northwards migration of M. macleayi from the Clarence and Evans Rivers and subsequent recruitment to the Evans and Richmond ocean fisheries respectively. Results indicate the importance of river discharge to production of M. macleayi and suggest that modification of discharges by restriction of freshwater flow could adversely effect production.

Distribution of the Platypus (Ornithorhynchus anatinus) in the Bombala River Catchment, South-Eastern New South Wales.

1998 ◽  
Vol 20 (2) ◽  
pp. 251
Author(s):  
R.W. Turnbull
Keyword(s):  
New South ◽  
New South Wales ◽  
River Catchment ◽  
South Eastern ◽  
South Wales ◽  
Ornithorhynchus Anatinus ◽  
The Difference

Distribution of the platypus (Ornithorhynchus anatinus) in the Bombala River catchment in south-eastern New South Wales was surveyed using questionnaires. Platypuses were reported from all streams in the catchment. The majority of positive sightings were from downstream areas whereas very few positive sightings were reported from headwater areas. The difference between frequencies of headwater and downstream reports of sightings was significant. The platypus was considered common throughout the catchment.

Partition of fat, body composition and body condition score in mature cows

1984 ◽  
Vol 38 (1) ◽  
pp. 23-32 ◽  
Author(s):  
I. A. Wright ◽  
A. J. F. Russel
Keyword(s):  
Body Composition ◽  
Body Fat ◽  
Body Condition ◽  
Fat Body ◽  
Body Condition Score ◽  
Subcutaneous Fat ◽  
The Body ◽  
Live Animal ◽  
Condition Score ◽  
Friesian Cows

ABSTRACTBody condition score, assessed subjectively on the live animal, was related to the directly determined body composition of 73 mature, non-pregnant, non-lactating cows of Hereford × Friesian, Blue-Grey, Galloway, Luing and British Friesian genotypes. Relationships between condition score and chemically determined body fat were all very highly significant, and considered to be of value for predictive purposes. Differences between genotypes in the proportion of fat stored in the main depots of the body resulted in differences in the relationship between condition score and body fat. British Friesian cows had a higher proportion of their fat in the intra-abdominal depots and the lowest proportion of subcutaneous fat, resulting in their being fatter at any given condition score. Hereford × Friesian cows had the highest proportion of subcutaneous fat and were thus the least fat at any condition score. One unit change in condition score was associated with a change of 2242 (s.e. 103) MJ of body tissue energy in Hereford × Friesian, Blue-Grey, Galloway and Luing cows and 3478 (s.e. 392) MJ in British Friesian cows. These figures may be used to bring a greater degree of precision to the nutritional management of beef and dairy cows.

scholarly journals Performance of steer progeny of sires differing in genetic potential for fatness and meat yield following postweaning growth at different rates. 2. Carcass traits

2009 ◽  
Vol 49 (6) ◽  
pp. 525 ◽  
Author(s):  
W. A. McKiernan ◽  
J. F. Wilkins ◽  
J. Irwin ◽  
B. Orchard ◽  
S. A. Barwick
Keyword(s):  
Production Systems ◽  
Carcass Traits ◽  
Quality Traits ◽  
Muscle Area ◽  
Eye Muscle ◽  
Meat Yield ◽  
Breeding Values ◽  
Genetic Potential ◽  
Estimated Breeding Values ◽  
Selection Of

The steer progeny of sires genetically diverse for fatness and meat yield were grown at different rates from weaning to feedlot entry and effects on growth, carcass and meat-quality traits were examined. The present paper, the second of a series, reports the effects of genetic and growth treatments on carcass traits. A total of 43 sires, within three ‘carcass class’ categories, defined as high potential for meat yield, marbling or both traits, was used. Where available, estimated breeding values for the carcass traits of retail beef yield (RBY%) and intramuscular fat (IMF%) were used in selection of the sires, which were drawn from Angus, Charolais, Limousin, Black Wagyu and Red Wagyu breeds, to provide a range of carcass sire types across the three carcass classes. Steer progeny of Hereford dams were grown at either conventional (slow: ~0.5 kg/day) or accelerated (fast: ~0.7 kg/day) rates from weaning to feedlot entry weight, with group means of ~400 kg. Accelerated and conventionally grown groups from successive calvings were managed to enter the feedlot at similar mean feedlot entry weights at the same time for the 100-day finish under identical conditions. Faster-backgrounded groups had greater fat levels in the carcass than did slower-backgrounded groups. Dressing percentages and fat colour were unaffected by growth treatment, whereas differences in ossification score and meat colour were explained by age at slaughter. There were significant effects of sire type for virtually all carcass traits measured in the progeny. Differences in hot standard carcass weight showed a clear advantage to European types, with variable outcomes for the Angus and Wagyu progeny. Sire selection by estimated breeding values (within the Angus breed) for yield and/or fat traits resulted in expected differences in the progeny for those traits. There were large differences in both meat yield and fatness among the types of greatest divergence in genetic potential for those traits, with the Black Wagyu and the Angus IMF clearly superior for IMF%, and the European types for RBY%. The Angus IMF progeny performed as well as that of the Black Wagyu for all fatness traits. Differences in RBY% among types were generally reflected by similar differences in eye muscle area. Results here provide guidelines for selecting sire types to target carcass traits for specific markets. The absence of interactions between growth and genetic treatments ensures that consistent responses can be expected across varying management and production systems.

Comparison of bicarbonate-extractable soil phosphorus measured by ICP-AES and colourimetry in soils of south-eastern New South Wales

Soil Research ◽  
2009 ◽  
Vol 47 (7) ◽  
pp. 742 ◽  
Author(s):  
M. R. Hart ◽  
P. S. Cornish
Keyword(s):  
Inductively Coupled Plasma ◽  
New South ◽  
Soil Phosphorus ◽  
New South Wales ◽  
Soil Samples ◽  
Available Phosphorus ◽  
Soil P ◽  
Inductively Coupled ◽  
South Wales ◽  
The Difference

Soil testing for plant-available phosphorus (P) in Australia is most commonly conducted using alkaline sodium bicarbonate extraction (Olsen or Colwell tests), followed by a colourimetric assay to measure the concentration of P in solution. Analysis by inductively coupled plasma (ICP) spectroscopy has become increasingly popular internationally for other soil P tests, especially Mehlich 3, due to its efficiency and ability to measure multiple elements in the one extract. The use of ICP in place of colourimetry has been used in some Australian laboratories for bicarbonate-extractable P. However, the method is known to measure forms of P (organic) that are not measured by the colourimetric assay. This study presents data comparing soil Colwell P measured by the 2 methods for 714 soil samples from pastoral sites in south-east New South Wales. Measurement by ICP consistently yielded significantly higher P concentrations than the colourimetric method (ICP-P = 1.122Col-P + 57.0, r2 = 0.95, P < 0.001). Differences between the 2 techniques were more marked in 0–20 mm than 0–100 mm depth soil samples, and in soils with greater clay contents, suggesting that the difference was related to soil organic matter, and thereby organic P contents. Relative differences were greatest in soils with lower P concentrations, i.e. within the agronomic optimum range of most interest to farmers. ICP analysis cannot be directly correlated with colourimetrically measured P in bicarbonate extracts, and would need to be developed and calibrated as a separate, new soil P test.

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