Hybrid vigour and lamb production. 1. Reproductive performance of the purebred and crossbred matings

1978 ◽  
Vol 18 (95) ◽  
pp. 745 ◽  
Author(s):  
BJ McGuirk ◽  
ME Bourke
Keyword(s):  
Reproductive Performance ◽  
Agricultural Research ◽  
New South ◽  
Research Station ◽  
Hybrid Vigour ◽  
Mating Activity ◽  
South Wales ◽  
Breed Difference ◽  
The Difference ◽  
Mixed Flock

An experiment was conducted at Cowra Agricultural Research Station, New South Wales, to determine the importance of hybrid vigour to the productivity of crosses between Border Leicester and Merino sheep. In five years, 1963 to 1967, Border Leicester (BL) and Merino (M) rams were paddock-joined to a mixed flock of ewes of both breeds for five weeks in March-April. The results of these purebred and crossbred matings have been compared. Cummulative weekly raddle counts were similar for both purebred mating groups (BL x BL and M x M) and by the end of joining over 95 per cent of ewes in both groups had been raddled. When the mating data for the Border Leicester ewes were examined, Merino rams raddled fewer ewes than did Border Leicester rams. This breed difference between rams was significant for the number of ewes raddled by the end of both the first and second week of joining (P < 0.05) and the difference in favour of the Border Leicester rams was still apparent at the end of joining (97 vs. 86 per cent, not significant). The reproductive performance of the Merino ewes (M x M) was superior to that of the- Border Leicesters (BL x BL), with 1.05 vs. 0.93 lambs born per ewe joined. The Border Leicester flock had higher incidences of both dry ewes (63.7 vs. 79.3 per cent ewes lambing of those joined) and multiple births (1.47 vs. 1.33 lambs born per lambing ewe). Because of the difference in the mating activity of the two Border Leicester ewe flocks (M x BL vs. BL x BL), the most reliable estimates of the relative performance of purebred and crossbred matings were given by the number of lambs born per lambing ewe, and the number of ewes lambing to first service. The crossbred matings were superior for both characteristics, by 4.6 and 5.7 per cent respectively, but neither difference was statistically significant.

Seasonal variation in the fertility and fecundity of Bungaree and Peppin Merinos in central-western New South Wales

1969 ◽  
Vol 9 (37) ◽  
pp. 151 ◽  
Author(s):  
JR Giles ◽  
JP Drinan
Keyword(s):  
Seasonal Variation ◽  
Agricultural Research ◽  
New South ◽  
New South Wales ◽  
Ovulation Rate ◽  
Research Station ◽  
Agricultural Research Station ◽  
South Wales

The seasonal variation in fertility and fecundity of Bungaree and Peppin Merinos was compared at the Agricultural Research Station, Trangie, New South Wales. Ewes of both strains were joined to rams of both strains for 32 days on nine occasions ; each joining being separated from adjacent periods by an interval of 10 days. For six weeks after joining the ewes were run with vasectomized rams and were then slaughtered over the following six weeks. Incidence of oestrus and ovulation rate of the two strains were similar at all times. More Bungaree than Peppin ewes returned to service, particularly during the autumn, irrespective of the strain of rams to which they were joined. There was no difference between ram strains in percentage of ewes returning to service or percentage of ewes pregnant, but a significantly higher proportion of ova were lost in pregnant ewes with multiple ovulations after joining to Bungaree rams in winter and spring.

Skin folds and Merino breeding. 8. Fertility of individual rams in flocks selected for high and low skin fold

1969 ◽  
Vol 9 (37) ◽  
pp. 147 ◽  
Author(s):  
BJ McGuirk
Keyword(s):  
Artificial Insemination ◽  
Agricultural Research ◽  
New South ◽  
New South Wales ◽  
Research Station ◽  
South Wales ◽  
Skin Fold ◽  
Single Character ◽  
Lower Fertility ◽  
Selection For

Single character selection flocks-Folds Plus (selection for high fold score) and Folds Minus (selection for low fold score) were established in 1951 from a Peppin Merino flock at Trangie Agricultural Research Station, New South Wales. For the period 1951 to 1966, 25 per cent of rams selected for the Folds Plus flock were rejected following semen examination before joining, compared to only three per cent of Folds Minus rams (P<0.05). The fertility of individual rams in the two flocks has been estimated from the lambing performance of the ewes to which they were mated in the period 1951 to 1963. Averaged over the twelve joinings, a higher proportion of ewes mated to Folds Minus rams lambed following both artificial insemination (53 v. 45 per cent) and paddock joinings (57 v. 47 per cent). The lower fertility of the Folds Plus rams was not due to a higher proportion of completely infertile rams.

Wool production, ground cover and botanical composition of pastures grazed by Merino wethers in central western New South Wales. 2. Barrel medic pasture

1973 ◽  
Vol 13 (64) ◽  
pp. 510 ◽  
Author(s):  
H Brownlee
Keyword(s):  
Agricultural Research ◽  
New South ◽  
Ground Cover ◽  
Additional Treatment ◽  
Research Station ◽  
Botanical Composition ◽  
Stocking Rate ◽  
Barrel Medic ◽  
South Wales ◽  
Pasture Area

Two grazing experiments were performed between 1965 and 1969 at the Agricultural Research Station, Condobolin, to determine the carrying capacity of Jemalong barrel medic (Medicago truncatula) pasture. In each experiment the pasture was set stocked with Merino wethers at 3.1, 4.1 and 6.2 ha-1. An additional treatment stocked at 6.2 ha-1 was included in which two-thirds of the pasture area was saved during autumn or periods of feed shortage while stock were confined to the other one-third. In both experiments the pasture supported 3.1 wethers ha-1 under set stocking for three years with little supplementary feeding and regenerated successfully each year. No major changes in botanical composition were recorded, and Jemalong medic remained the major component of the pasture. Autumn saving at 6.2 ha-1 mitigated the effects of the high stocking rate on both animal and pasture, but did not result in worthwhile animal production increases.

Hybrid vigour and lamb production. 2. Effects on survival and growth of first-cross lambs, and on wool and body measurements of hogget ewes

1978 ◽  
Vol 18 (95) ◽  
pp. 753 ◽  
Author(s):  
BJ McGuirk ◽  
ME Bourke ◽  
JM Manwaring
Keyword(s):  
Agricultural Research ◽  
Fibre Diameter ◽  
Fibre Length ◽  
Research Station ◽  
Hybrid Vigour ◽  
Body Measurements ◽  
South Wales ◽  
Survival And Growth ◽  
Lamb Survival ◽  
Fleece Weight

In an experiment at Cowra Agricultural Research Station, New South Wales, five drops of Border Leicester (BB), Merino (MM), Border Leicester x Merino (BM) and Merino x Border Leicester (MB) lambs have been compared to estimate hybrid vigour effects on lamb survival and growth, and on the wool and body measurements of ewe hoggets. Hybrid vigour has been estimated as the percentage superiority of the crossbreds 1/2(MB + BM) over the average of the purebred 1/2(BB + MM) flocks. Hybrid vigour was observed for lamb survival, with the crossbreds superior by 10 per cent in lambs weaned per lamb born (P < 0.05). The crossbred lambs were also heavier at birth (4 per cent) and weaning (6 per cent) and crossbred wether lambs were 11 per cent heavier at slaughter (all P < 0.05). The crossbred ewes were significantly superior to the average of the purebred flocks in both greasy (8 per cent) and clean fleece weight (12 per cent), liveweight (12 per cent) and chest depth (5 per cent) (all P < 0.05). There was no evidence that the crossbreds were superior in any component of wool production per unit area of the skin ; fibre length, fibre diameter or follicle density. Other evidence from this experiment indicates that the breeds and crosses differ in their susceptibility to pneumonia and that there may be heterosis for resistance. This situation could give rise to heterosis for production characters and the heterosis estimates obtained may only be applicable to first-cross flocks derived from Border Leicester studs which are susceptible to pneumonia. Lamb survival to weaning was higher for purebred Merinos (88 per cent) than for purebred Border Leicesters (73 per cent, P < 0.05). The Border Leicester lambs were heavier at all ages and in all years, although the magnitude of their superiority varied significantly between years (P < 0.05). This breed x year interaction was also significant for clean fleeca weight, but the average production of the two groups was similar over the five years. Variation, measured as the coefficient of variation, was generally lower within the crossbred flocks for those characters for which hybrid vigour effects were observed, but these differences were not statistically significant.

The value to Merino ewes and lambs of continued superphosphate topdressing on a subterranean clover pasture ley

1976 ◽  
Vol 16 (79) ◽  
pp. 197 ◽  
Author(s):  
OR Southwood ◽  
DG Saville ◽  
AR Gilmour
Keyword(s):  
Body Weight ◽  
Agricultural Research ◽  
New South ◽  
New South Wales ◽  
Subterranean Clover ◽  
Research Station ◽  
Stocking Rate ◽  
Wool Production ◽  
South Wales ◽  
Clover Pasture

In an experiment at the Agricultural Research Station, Temora, New South Wales, Merino breeding ewes with their lambs grazed continuously from 1966 to 1970 at three stocking rates, 5, 7.5 and 10 ewes ha-1, on annual Trifolium subterraneum clover pasture topdressed every autumn with superphosphate fertilizer at nil, 94 or 188 kg ha-1. Stocking rate had an effect on ewe body weight in autumn each year and in winter and spring of the last year but it had no effect no wool production per ewe. Apart from the dry year, stocking rate had no effect on lamb performance. Superphosphate had little effect on ewe body weight and none on wool production but there were more lambs on the fertilized treatments than on the unfertilized pastures in 1967 when rainfall was low. Fertilizer encouraged barley grass dominance whereas the pasture not topdressed grew more clover and produced more burr. With no topdressing, available soil phosphate declined steadily over the five years to less than half the initial level. The results indicate that in a spring lambing, Merino ewe enterprise in the southern New South Wales wheat belt, where clover-ley farming is the general practice, annual pasture topdressing is no longer necessary after approximately 1000 kg ha-1 superphosphate has been applied to the soil and the fertilizer is continued through the cropping phase.

Skin folds and Merino breeding. 4. The susceptibility of rams selected for a high degree of skin wrinkle to heat induced infertility

1966 ◽  
Vol 6 (21) ◽  
pp. 121 ◽  
Author(s):  
DG Fowler ◽  
RB Dun
Keyword(s):  
Heat Treatment ◽  
Agricultural Research ◽  
New South ◽  
Conception Rate ◽  
Research Station ◽  
Merino Sheep ◽  
South Wales ◽  
Selection Experiments ◽  
High Degree

Three experiments were done to establish whether differences in ram fertility could explain some of the differences in reproductive performance observed between two flocks of Merino sheep, one flock of which had been bred for a high (Folds Plus) and the other for a low (Folds Minus) degree of skin wrinkle at the Trangie Agricultural Research Station. In the first experiment the quality of semen collected from Folds Plus and Folds Minus rams at Glenfield, New South Wales, was examined during the period December 1962 until March 1963. From late January until early March 1963, Folds Plus rams had low quality semen which gave a conception rate of 38.6 per cent. Over the same period, Folds Minus rams had higher quality semen which gave a conception rate of 58.6 per cent. Folds Plus and Folds Minus rams were then subjected to a severe heat treatment in mid winter 1963 (experiment 2) which produced severe seminal degeneration in both Folds Plus and Folds Minus rams. Folds Plus rams were more susceptible to heat than Folds Minus rams since the semen of Folds Plus rams remained degenerate for a longer period than the semen of Folds Minus rams and, in a test mating program, fewer pregnancies were observed in ewes artificially inseminated with the semen of Folds Plus rams than in ewes inseminated with the semen of Folds Minus rams. In a third experiment Folds Plus and Folds Minus rams from two independently established selection experiments at Trangie and at Cunnamulla were subjected to a heat treatment. The heated Folds Plus rams from both selection experiments exhibited marked seminal degeneration, but heated Folds Minus rams from both selection experiments maintained high quality semen throughout the experiment. The heated Folds Plus rams from Cunnamulla were more severely affected than the heated Folds Plus rams from Trangie.

Lucerne persistence and the productivity of ewes and lambs grazed at two stocking rates within different management systems

1975 ◽  
Vol 15 (77) ◽  
pp. 747 ◽  
Author(s):  
OR Southwood ◽  
GE Robards
Keyword(s):  
Plant Density ◽  
Agricultural Research ◽  
New South ◽  
Research Station ◽  
Stocking Rate ◽  
South Wales ◽  
Continuous Grazing ◽  
Rotational Systems ◽  
Stocking Rates ◽  
Lamb Growth

From 1967 to 1971 a grazing experiment was conducted at the Agricultural Research Station, Temora, New South Wales with Merino ewes and first cross spring lambs on lucerne pastures. Set stocking was compared with a number of rotational systems at twice replicated stocking rates of five and ten ewes ha-1. The rotational systems consisted of either five or seven paddocks each grazed to give a constant pasture recovery time of 36 days year round, or 36 days mid-summer to mid-winter and 24 days when lambs were present. Stocking rate was the only variable affecting ewe wool production and body weight. During the driest year the constant rotation was the best treatment, whereas in the wetter year ewes managed in a variable rotation grew most wool. The number of lambs born and their birth weight did not vary among treatments. Growth rate was slower at the higher stocking rate but the management treatments had no effect on lamb growth. Lucerne plant density decreased by half during the first three years of the experiment. Thereafter plant density was maintained in the rotationally grazed systems. Under continuous grazing at the high stocking rate no lucerne survived after four months but at the low stocking rate most remaining plants died after a spring drought in 1971.

scholarly journals Economic effects of nutritional constraints early in life of cattle

2009 ◽  
Vol 49 (6) ◽  
pp. 479 ◽  
Author(s):  
A. R. Alford ◽  
L. M. Cafe ◽  
P. L. Greenwood ◽  
G. R. Griffith
Keyword(s):  
Agricultural Research ◽  
New South ◽  
High Standard ◽  
Economic Effects ◽  
Research Station ◽  
Northern Coast ◽  
Gross Margin ◽  
South Wales ◽  
Gross Margins

An experiment was conducted at the Grafton Agricultural Research Station on the northern coast of New South Wales whereby low and high pasture nutritional systems were imposed on a herd of Hereford cows during pregnancy and from birth to weaning in a factorial design. Offspring representing extremes of growth to birth and/or weaning were then selected for study of long-term consequences of growth early in life. Implications of the nutritional treatments of cows on subsequent weaning rates were also tested with data from previous studies. The extent to which these extreme maternal nutritional and offspring growth scenarios affected herd profitability was tested with the Beef-N-Omics decision support package. For the representative cattle enterprise modelled, gross margin per hectare ranged from $A114 to $A132. In all cases, the gross margin for those groups with fetal growth based on a higher level of nutrition exceeded that of their peers on a lower level of nutrition. It is more profitable for cows and calves to have access to a high standard of nutrition during pregnancy and up to weaning than for them to have access only to a poor standard of nutrition. Incorporating differential weaning rates following maternal nutritional treatments reduced gross margins per hectare by up to 30%. On average, a 1% reduction in weaning rate resulted in a 4.5% reduction in gross margin. Restricted cow–calf nutrition affects the future cow fertility, as well as the current calf progeny, economically.

Mating activity and reproductive performance in Merino flocks where ram percentages are 1.0, 0.5 and 0.25

1982 ◽  
Vol 22 (117) ◽  
pp. 268 ◽  
Author(s):  
DG Fowler
Keyword(s):  
Direct Observation ◽  
Reproductive Performance ◽  
New South ◽  
New South Wales ◽  
Physical Contact ◽  
Mating Activity ◽  
South Wales ◽  
Service Activity ◽  
Second Period

Mature Merino rams were joined at rates of one ram to 100 ewes (1.0%), one ram to 200 ewes (0.5%) and one ram to 400 ewes (0.25%) in paddocks at Richmond, New South Wales. Fresh rams were introduced each day of joining and mating activity was measured and behaviour was studied by direct observation. Thirty-eight days after the removal of entire rams, the ewes were slaughtered and reproductive tracts were collected and examined. As ram percentage fell so also did services per ewe (4.3 to 2.2), number of ewes that mated (6.2 to 3.3/d) and the percentage of ewes that became pregnant (88.8 to 60.4%). Ram service activity remained constant as the number of ewes per ram increased. There were increases in the number of oestrous ewes in physical contact with and crowding the rams and in the number of ewes returning to be served in the second period of joining. The study suggests that the percentage of mature Merino rams joined with mature Merino ewes should not be less than one, because below this value, reproductive performance declines. The decline may be due to oestrous ewes crowding around the ram, thus preventing rams from increasing service activity thereby reducing services per ewe, ewes mated and ewes pregnant.

Cumulative reproductive performance effect on overall lifetime productivity in Merino sheep

2018 ◽  
Vol 58 (8) ◽  
pp. 1470
Author(s):  
J. S. Richards ◽  
M. A. Sladek ◽  
G. J. Lee
Keyword(s):  
Reproductive Performance ◽  
New South ◽  
Dental Health ◽  
Age Groups ◽  
The South ◽  
Performance Effect ◽  
South West ◽  
South Wales ◽  
The Impact ◽  
Effect Of Age

Reproduction is an important driver of profitability in commercial sheep flocks. Historically, Merino flocks have been run with a fixed age structure, ignoring individual merit and casting for age at a specific age. More recently, research has focussed on utilising the variation within age groups by keeping productive older ewes longer and culling less productive ewes earlier. Previous studies have also examined the effect of age on reproduction and the impact of reproduction status on productivity, but little research has been conducted on cumulative effects of reproductive performance on later productivity, reproduction and health. The present study examined the impact of higher lifetime reproduction on other key production and fitness traits in older ewes run under commercial conditions. Data were collected from two commercial wool-producing properties in the South West Slopes and the Central West Plains of New South Wales during 2009–2011. Reproduction, fleece measurements, bodyweight and condition and dental health were recorded during the study. The results showed that age had a bigger effect on productivity and dental health than did cumulative lifetime reproduction. Environment and genetics determined the level of impact, with minimal loss in productivity from increased age of animals occurring in the South West Slopes flock, whereas the Central West Plains flock would appear to require closer monitoring of productivity as ewes aged. The data collected did not allow separation of the genetic and environmental influences within the study. Retaining animals with a higher reproductive performance past normal culling age does not necessarily result in reduction of productivity or ewe health, but this must be monitored.

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