A note on the effect of live weight at mating on fertility of Awassi ewes in semi-arid north-west Syria

1988 ◽  
Vol 47 (3) ◽  
pp. 505-508 ◽  
Author(s):  
E. F. Thomson ◽  
F. A. Bahhady

Ninety Awassi ewes managed at different levels were used to study the effect of live weight mating on fertility over 3 years in semi-arid north-west Syria. During the 56-day pre-mating period fertile ewes had higher daily live-weight gains than infertile ewes (P < 0·01), frequency of oestrous cycles increased as live weight increased (P < 0·001) and fertile ewes tended to have more frequent oestruses than infertile ewes (P > 0·05). Ewe fertility was related (r = 0·87) to live weight at mating and twinning reached a maximum (four per 100 ewes lambing) in 51· to 56-kg ewes then decreased fP > 0·05). Maximum fertility can be expected in Awassi ewes weighing over 48 kg at mating in north-west Syria.

2005 ◽  
Vol 32 (2) ◽  
pp. 140-148 ◽  
Author(s):  
H. RICARDO GRAU ◽  
N. IGNACIO GASPARRI ◽  
T. MITCHELL AIDE

In Argentina, deforestation due to agriculture expansion is threatening the Semi-arid Chaco, one of the largest forested biomes of South America. This study focuses on the north-west boundary of the Argentine Semi-arid Chaco, where soybean is the most important crop. Deforestation was estimated for areas with different levels of soil and rainfall limitation for agriculture between 1972 and 2001, with a finer analysis in three periods starting in 1984, which are characterized by differences in rainfall, soybean price, production cost, technology-driven yield and national gross domestic product. Between 1972 and 2001, 588 900 ha (c. 20% of the forests) were deforested. Deforestation has been accelerating, reaching >28 000 ha yr−1 after 1997. The initial deforestation was associated with black bean cultivation following an increase in rainfall during the 1970s. In the 1980s, high soybean prices stimulated further deforestation. Finally, the introduction of soybean transgenic cultivars in 1997 reduced plantation costs and stimulated a further increase in deforestation. The domestic economy had little association with deforestation. Although deforestation was more intense in the moister (rainfall >600 mm yr−1) areas, more than 300 000 ha have already been deforested in the drier areas, suggesting that climatic limitations are being overcome by technological and genetic improvement. Furthermore, more than 300 000 ha of forest occur in sectors without major soil and rainfall limitations. If global trends of technology, soybean markets and climate continue, and no active conservation policies are applied, vast areas of the Chaco will be deforested in the coming decades.


1957 ◽  
Vol 49 (2) ◽  
pp. 223-228 ◽  
Author(s):  
C. R. W. Spedding ◽  
T. H. Brown

1. The live-weight gain of lambs initially infected at five different levels was compared with that of similar but worm-free animals, under conditions of set-stocking at a high rate per acre.2. Over a period of 9 months the worm-free controls gained 67·7% more weight than the total infected group, but the live-weight gains of the five levels did not appear to be related to their original infection or to their egg counts.3. Although a few nematode eggs were detected in the faeces of some control lambs, reinfection was negligible under the conditions of this experiment.4. It was concluded that a marked depression of productivity may be associated with an egg count as low as 114 e.p.g. in sheep 4–7 months of age.


1979 ◽  
Vol 19 (97) ◽  
pp. 140 ◽  
Author(s):  
EJ Bowen ◽  
KG Rickert

At Gayndah, south-eastern Queensland, a native Heteropogon contortus pasture, sown to fine-stem stylo (Stylosanthes guianensis var. intermedia), and invaded by red natal grass (Rhynchelytrum repens), was grazed by weaner steers from June 1 in three treatments : heavy and light put-and-take grazing for five years from 1971, and set-stocked at 1.37 animals ha-1 for two years from 1974. Weight gains in the put-and-take treatments were not significantly different. The mean annual liveweight gain was 167 kg animal-1 at a mean equivalent stocking rate of 1.47 animals ha-1. Over the same period unsown native pasture, cleared of timber, gave a gain of 62 kg animal-1 at 0.62 animals ha-1. In all seasons except summer, weight gains declined linearly with stocking rate and in 1972-73, with a mean equivalent stocking rate of 2.66 animals ha-1, the annual gain was almost halved. When equivalent stocking rates were 0.9, 0.9, 1.8 and 1.2 animals ha-1 in winter, spring, summer and autumn, the respective gains were 4, 73, 65 and 45 kg animal-1. The set-stocked treatment had a mean annual gain of 147 kg animal-1. At another site 116 km north-west of Gayndah, two paddocks of Heteropogon contortus and fine-stem stylo were set-stocked with weaners over four years. One paddock had four applications of superphosphate of 250 kg ha-1. The mean annual liveweight gains were significantly different, being 154 and 143 kg animal-1 in the fertilized and unfertilized paddocks at mean stocking rates of 0.83 and 0.74 animals ha-1, respectively. In a grazing protection experiment the density of fine-stem stylo declined exponentially with an accumulation of pasture dry matter in spring and summer. Heavy continuous grazing, an annual hay cut and an accidental fire all increased the density of fine-stem stylo. Management options to maintain the density of fine-stem stylo and the relative importance of the legume and grass to animal production are discussed.


1986 ◽  
Vol 43 (2) ◽  
pp. 211-223 ◽  
Author(s):  
I. A. Wright ◽  
A. J. F. Russel ◽  
E. A. Hunter

ABSTRACTTwo experiments were conducted with weaned, suckled calves to investigate the effect of feeding level during the post-weaning winter on their subsequent performance when continuously grazed on pasture maintained at two sward heights. Low, medium and high levels of winter feeding resulted in winter live-weight gains of 0·31, 0·58 and 0·79 (s.e. 0·027) kg/day (P < 0·001) during the 152-day winter in experiment 1 and 0·44, 0·69 and 0·84 (s.e. 0·029) kg/day (P < 0·001) for 189 days in experiment 2. During summer (93 days in experiment 1 and 87 days in experiment 2) there was a significant effect of winter food level on performance when live-weight gains were 1·10, 1·02, 0·87 and 1·35, 1·23 and 1·19 (s.e. 0·060) kg/day for the low, medium and high winter food levels on the short and tall swards respectively in experiment 1 (P < 0·01) and 0·86, 0·66, 0·51 and 1·26, 1·18 and 0·91 (s.e. 0090) kg/day in experiment 2 (P < 0·001). The cattle showing compensatory growth had higher herbage intakes and it is postulated that this occurred because of a negative association between body fat and herbage intake. Sward height had a large positive effect on herbage intake and live-weight gain and it is concluded that for maximum intake on ryegrass swards, herbage height should be at least 8 cm. Lower levels of winter live-weight gain delayed the time to slaughter, but allowed cattle to achieve heavier carcass weights at a fixed level of fatness.It is concluded that there is no single optimum winter food level for weaned, suckled calves but that the choice will depend upon several factors, including availability of winter and summer food resources, the length of the winter feeding period, the desired date of slaughter and type of carcass to be produced.


1964 ◽  
Vol 62 (1) ◽  
pp. 123-149 ◽  
Author(s):  
R. G Gunn

1. Over 3 years, different levels of first winter nutrition created the following live-weight differences between groups of North and South Country Cheviot ewe hoggs at 12 months of age. High plane (H.P.) and mid-plane (M.P.) fed groups born 1956 were 34–35% and 11–13% heavier, respectively, than low plane (L.P.) fed groups, H.P. and M.P. fed groups born 1957 were 47–57% and 18–24% heavier, respectively, than hill-wintered groups. Away wintered groups born 1958 were 9–12% heavier than hill-wintered groups. All group differences were highly significant.2. From 12 months onwards all groups were run together on the same hill and received similar management. Live weight and live measurement response of the total treatment groups and of the heavy and light hoggs within the groups prior to treatment were studied over the summer after treatment from 12 to 18 months.


1972 ◽  
Vol 15 (3) ◽  
pp. 215-227 ◽  
Author(s):  
C. E. Hinks ◽  
J. H. D. Prescott

SUMMARYTwenty-four Friesian steers, initially 5 months of age, were involved in a 2 × 2 factorial experiment which spanned grazing and silage feeding periods of 22 weeks' duration. In the first period, cattle were stocked at a uniformly high density, with half of the group being fed 1·25 kg/head per day of supplementary barley. In the second period, the cattle were subdivided into four groups and fed varying levels of barley with silage. Finally all the animals received 3·65 kg/head per day of barley. Replicates of the four treatments were slaughtered at random after 5 to 11 weeks on this treatment. Whilst supplementary cereal feeding significantly increased the live-weight gains of steers at grass by 11%, this live-weight advantage was offset by their slower gains in the final weeks before slaughter. Feeding cereals to grazing cattle had little effect on carcass composition or the proportions of carcass joints, but their beef was considered, by a tasting panel, to be more tender than the meat from the control steers.Increasing the level of barley fed with silage only increased live-weight gains by 2%, and had little effect on carcass or meat quality.


1970 ◽  
Vol 12 (1) ◽  
pp. 23-36 ◽  
Author(s):  
T. T. Treacher

SUMMARY1. Scottish Half-bred ewes carrying twin foetuses were fed individually to make live-weight gains in the last six weeks of pregnancy of (1) 20%, (2) 10% and (3) 0% of their live weight in week 14 of pregnancy. In lactation the ewes were fed ad libitum. The lambs were removed 12 to 16 hr after parturition and the ewes were machine-milked twice daily for the first six weeks of lactation.2. Total birth weights per ewe of twin lambs from the treatments were (1) 10·10 kg, (2) 9·44 kg and (3) 8·18 kg and differed significantly.3. The level and pattern of voluntary intake in lactation did not differ significantly between the treatments. Total dry-matter intakes in the six weeks of lactation were (1) 121·9 kg (2) 105·9 kg and (3) 109·5 kg.4. The pregnancy treatments affected the level of milk production and the shape of lactation curves. The total yields in the first six weeks of lactation were (1) 58·8 kg, (2) 43·5 kg and (3) 26·9 kg. Higher contents of fat and protein and the lower content of lactose in the milk from treatment-3 ewes on days 1 and 3 of lactation indicated a slower onset of lactation in these ewes. Between days 7 and 35 of lactation the contents of fat and SNF were lowest on treatment 3 but the differences were not significant.5. The live-weight changes in lactation, which were in inverse order to the gains in late pregnancy, were (1) 3·4 kg, (2) 5·5 kg and (3) 9·5 kg.


1998 ◽  
Vol 66 (1) ◽  
pp. 93-104
Author(s):  
D. W. Hennessy ◽  
P. J. Williamson ◽  
D. J. McLennan ◽  
R. J. Farquharson ◽  
S. G. Morris ◽  
...  

AbstractSubtropical grasslands are low in organic matter digestibility (OMD) (0·60) and nitrogen (N) (15 g/kg) for much of the year and this limits cattle production which is characterized by low calving rates and low weaning weights. Production has been based on Bos taurus British breeds of cattle but this is changing and now many breeding herds comprise B. indicus cows and their crosses. This change has increased some aspects of production, but low calving rates persist.A 4-year study was undertaken with a view to improve calving rates and weaner output by supplementing cows grazing either native or improved pastures with a high protein oilseed meal (cottonseed meal; CSM) on four sites. These sites were subdivided into a total of 36 paddocks to allow for two replications in a 3 breeds × 3 supplementation rates × 2 pastures factorial design. Selected cows (no. = 216) from Hereford (H), Brahman (B) and Brahman × Hereford (BH) breed types were set to graze either native pastures (0·45 to 0·62 OMD, 8 to 15 gN per kg; low quality) or improved pastures (0·47 to 0·67 OMD, 10 to 22 g N per kg; medium quality). Cows were given either 0, 750 or 1500 glday of CSM for 130 days from calving until 4 weeks into a 12- to 13-week mating period. The CSM was given as two meals per week.Live weight at mating of cows on the low quality pasture was increased (P < 0·01) over those not supplemented by feeding either 750 g CSM per day (H and B cows) or 1500 g CSM per day (all cows). There was no significant effect of supplementation on the mating weights ofB cows grazing the medium quality sites. Calving rate ofB cows was not increased by their supplementation on either low (4-year mean 58·3 %) or medium quality pastures (66·8%) but did tend to be higher in H cows when supplemented at 1500 g CSM per day on the low (66·7 v. 78·0 (s.e. 6·09) %; P < 0·1) and medium quality pastures (70·5 v. 93·5 (s.e. 4·72) %). An increased calving rate (65·8 (s.e. 6·6) % to 83·2 (s.e. 5·82) % in supplemented BH cows grazing low quality pastures approached significance (P < 0·1) when given CSM at 1500 glday but there was no increased trend in calving rate when this breed type was supplemented on medium quality pastures.Weaning weights of calves from and B and BH cows were increased (P < 0·05) by supplementation of their dams at 750 glday and for calves weaned from H cows supplemented at 1500 glday of CSM. Supplementation at 1500 glday on low quality pastures increased weaner output per cow mated by 120% for H, by 65% for BH cows and by 50% for B cows. Weaner output was increased by 34 and 40%, respectively, for B and H cows when supplemented at 750 glday and grazing medium quality pastures but there was no significant effect of supplementation on output from BH cows. Responses in many parameters differed between years. These results were interpreted as a response to the protein in the oilseed meal supplement by B. taurus and B. taurus × B. indicus cross cows grazing on the subtropical pastures. The study also highlighted that responses to the meal differed between breed types, between the quality of the grazed pasture and between the years of supplementation.


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