Effect of Haemonchus contortus on productivity of ewes, lambs and weaners in a semi-arid environment

1992 ◽  
Vol 118 (2) ◽  
pp. 245-248 ◽  
Author(s):  
D. H. Cobon ◽  
B. M. O'Sullivan
Keyword(s):  
Milk Yield ◽  
Haemonchus Contortus ◽  
Clinical Signs ◽  
Arid Environment ◽  
Treated Group ◽  
North West ◽  
Wool Growth ◽  
Third Stage ◽  
Lamb Growth ◽  
Semi Arid

SUMMARYLactating ewes, ewes that had lambed but subsequently lost their lambs (dry) and weaners were either artificially infested with 2000–3000 third-stage Haemonchus contortus larvae (parasitized) or drenched with levamisole (treated) and run under extensive grazing conditions in north-west Queensland. Worm egg counts in parasitized lactating, dry and weaner sheep ranged from 860–2830 eggs per gram of faeces. These levels of infestation significantly (P < 0·01) reduced liveweight gain of all three sheep classes, milk yield of ewes and wool growth of weaners compared to their treated counterparts. The lower milk yield of the parasitized ewes significantly (P < 0·01) reduced lamb growth rate. Survival of lambs to weaning was 26% higher in the treated group. The experiments showed that moderate levels of H. contortus, that did not produce clinical signs of infestation, reduce productivity of sheep in this semi-arid environment.

The use of urea to improve milk yields and lamb survival of Merinos in a dry tropical environment

1981 ◽  
Vol 32 (3) ◽  
pp. 497 ◽  
Author(s):  
RGA Stephenson ◽  
JC Edwards ◽  
PS Hopkins
Keyword(s):  
Milk Yield ◽  
Survival Rates ◽  
Arid Environment ◽  
Poor Quality ◽  
Growth And Survival ◽  
Nitrogen Intake ◽  
C 30 ◽  
C 50 ◽  
Sorghum Grain ◽  
Lamb Growth

Urea supplementation of lambing Merino ewes increased milk yield and lamb growth and survival rates in both pen and paddock studies. These productivity gains occurred in a semi-arid environment characterized by poor reproductive efficiency in Merinos. In pens, urea supplenlents fed to lactating ewes at the rate of c. 12 g/day stimulated intake of poor quality pasture hay (0.9 %nitrogen) by c. 30% and increased total nitrogen intake by c. 100%. Milk yield was improved by c. 50% and lamb growth rate by c. 140%. Sorghum grain supplements stimulated milk yield and lamb growth to a lesser extent than urea. The correlations found in pen studies between nitrogen intake and milk yield of ewes (r � 0.85; P < 0.05), and between ewe milk yield and lamb growth (r % 0.80; P < 0.01), prompted further investigations under paddock conditions. Ewes grazing dry pastures and supplemented with urea (8-10 glday) via drinking water yielded more milk (11-32%) than unsupplemented counterparts. Similarly, there were improvements in lamb growth (80-100%) and survival (c. 10%) in the supplemented groups.

Response of wheat cultivars to dates of sowing under dryland conditions

1983 ◽  
Vol 101 (3) ◽  
pp. 727-733 ◽  
Author(s):  
R. De ◽  
G. Saran ◽  
B. B. Turkhede ◽  
R. B. Lal ◽  
R. K. Singh ◽  
...  
Keyword(s):  
High Temperatures ◽  
Spring Wheat ◽  
Vegetative Growth ◽  
Field Experiments ◽  
Arid Environment ◽  
Seedling Stage ◽  
Wheat Cultivars ◽  
North West ◽  
Early Differentiation ◽  
Semi Arid

SUMMARYField experiments made for 4 years between 1976–7 and 1979–80 in a semi-arid environment of north-west India showed that the productivity of dryland unirrigated wheat can be increased considerably by adjusting the date of sowing to conducive atmospheric temperatures. Sowing in the middle of November when daily mean temperatures ranged between 19 and 21 °C produced yields ranging between 2·6and 3·5t/ha (averaged over the 4 years) compared with 1·4–3·3 t/ha obtained from the crop sown by mid-October when the daily mean temperature ranged between 24 and 26 °C. The tall cultivar C 306, a derivative of winter x spring wheat cross, could withstand sowing at higher temperatures (mid-October) more than the spring wheats. High temperatures prevailing during the seedling stage of spring wheats shortened their vegetative growth and initiated early differentiation. Night temperatures above 13 °C coupled with day temperatures of 33–35 °C in the last fortnight of October adversely affected the tillering of spring wheats sown on 15 October and produced smaller spikes with few fertile spikelets.

scholarly journals How to determine the effective discharge and its return period in a semi-arid basin? The case of the Wadi Sebdou, Algeria (1973–2004)

2018 ◽  
Author(s):  
Abdesselam Megnounif ◽  
Sylvain Ouillon
Keyword(s):  
Arid Environment ◽  
Sediment Supply ◽  
Annual Series ◽  
North West ◽  
Sediment Rating Curve ◽  
Effective Discharge ◽  
The One ◽  
Log Normal ◽  
Load Discharge ◽  
Semi Arid

Abstract. Over a long multi-year period, flood events can be classified according to their effectiveness in moving sediments. Efficiency depends both on the magnitude and frequency with which events occur. In this study, the efficiency of the Wadi Sebdou (North-West Algeria), in a semi-arid environment, is examined through its histogram of sediment supply by discharge classes, established from 31-years of measurements. The effective (or dominant) discharge is the one whose class corresponds to the maximum sediment supply. Three types of subdivisions into discharge classes were compared. The subdivision in classes of equal amplitudes and the subdivision with equivalent discharges were those which allowed a correct distribution of frequencies and supplies of water and sediments. The effective discharges for these two subdivisions were close and almost equal to the half load discharge, i.e. to the flow rate corresponding to 50% of the cumulative sediment yield. The substitution of the flow histogram by a probability relationship and the use of a sediment rating curve enable to infer a theoretical value of the effective discharge. In this basin with strongly irregular flows, the introduction of a probability distribution was tested and assessed, analytical solutions are provided, but the Log-normal and Log-Gumbel laws highly underestimated the effective discharge. Return periods, estimated from the annual series of maximum discharge and half-load discharge, were compared. The former gives the period between hydrological years with discharges higher than the effective discharge (around 2 years), and the latter shows that more than half of the yearly sediment supply is carried by flows higher than the effective discharge only every 7 hydrological years. The study finally emphasized that the distribution of suspended load as a function of liquid discharge was sensitive to the basin and its forcings. On the Wadi Sebdou, the distribution of the sediment load, bimodal before 1988, became essentially monomodal after this date.

CASE STUDY: Evaluation of Different Cooling Systems in Lactating Heat-Stressed Dairy Cows in a Semi-Arid Environment

2007 ◽  
Vol 23 (5) ◽  
pp. 546-555 ◽  
Author(s):  
R. Burgos ◽  
L.J. Odens ◽  
R.J. Collier ◽  
L.H. Baumgard ◽  
M.J. VanBaale
Keyword(s):  
Dairy Cows ◽  
Arid Environment ◽  
Cooling Systems ◽  
Study Evaluation ◽  
Semi Arid
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