Cattle manure effects on structural stability and water retention capacity of a granitic sandy soil in Zimbabwe

The evaluation of soil aggregate stability and water retention is important in the assessment of soil management options. A 3-year study was conducted in 1999 to determine the effects of two cattle manure application methods on soil aggregate stability and water retention capacity of a sandy soil (Haplic Lixisol). Manure application increased soil organic C by 10–38% in the 0–10 cm layer. Compared with the control, manure management treatments increased the aggregate stability of soil as measured by the mean weight diameter (MWD) and aggregates between 2 and 10 mm (AGG2) indices from 0.243 to 0.733–0.926 mm, and from 27.3 to 128.3–148.3 g kg⁻¹, respectively. The readily available water (RAW) capacity of the soil was significantly increased by manure addition, whereas the increase in AWC was not significant. The increase in water retention capacity in the soil was more affected at low suctions and this was related to the effects of manure on macroporosity. It was concluded that cattle manure was beneficial to the structural stability and water retention of this soil.     

Prevalence of gastrointestinal helminths and anthelmintic resistance on small-scale farms in Gauteng Province,South Africa

Tropical Animal Health and Production - The present study was conducted to determine the prevalence and distribution of gastrointestinal helminths, to detect the presence of anthelmintic resistance...     

A study of some infectious causes of reproductive disorders in cattle owned by resource-poor farmers in Gauteng Province, South Africa

Two hundred and thirty-nine cattle from Gauteng Province in South Africa were tested for various pathogens causing reproductive diseases includingbovine viral diarrhoea/mucosal disease (BVD/MD) virus, infectious bovine rhinotracheitis/infectious pustular vulvovaginitis (IBR/IPV) virus, Neospora caninum and Brucella abortus usingvarious tests. For BVD/MD virus, 49.37% tested positive, 74.47% for IBR/IPV virus, 8.96% for Neospora caninum and 3.8% for Brucella abortus. The result for Brucella abortus is higher than the national average, possibly due to the small sample size. A high seroprevalence of antibodies to both BVD/MD virus and IBR/IPV virus was evident. These 2 viruses should be considered, in addition to Brucella abortus, when trying to establish causes of abortion in cattle. The clinical significance of Neospora caninum as a cause of abortion in Gauteng needs further investigation. One hundred and forty-three bulls were tested for Campylobacter fetus and Trichomonas fetus, and a low prevalence of 1.4% and 2.1% respectively was found in this study. The clinical implications of these findings are discussed.     

Effect of annual sequence of removing or flaming potato vines and fumigating soil on verticillium wilt of potato

The effects of removing or flaming potato vines and soil fumigation on population density ofVerticillium dahliae in soil, severity of Verticillium wilt, and tuber yield were studied in a field near Alliston, Ontario, between 1993 and 1996. Vines were physically removed or flamed using a propane flamer in September just before harvest and soil was fumigated with metam-sodium (Vapam) at 550 L/ha in October after harvest. Vine removal had no effect on soil populations ofV. dahliae, area under the disease progress curve (AUDPC), or tuber yield. Flaming once (1993), twice (1993 and 1994), or three (1993,1994, and 1995) times reduced the soil population density ofV. dahliae, and flaming twice (1993 and 1994) reduced AUDPC compared to the nontreated control, but had no effect on tuber yield. Fumigation once (1993) or twice (1993 and 1994) reduced pathogen density in soil and AUDPC, but did not increase tuber yield. Fumigation once (1993) or twice (1993 and 1994), in combination with flaming twice (1993 and 1994), was equally and significantly effective in reducing both population density ofV. dahliae in soil and AUDPC values and in increasing tuber yield in 1995. Annual flaming of vines in combination with soil fumigation once (1993) or twice (1993 and 1994) in the fall improved the control of Verticillium wilt of potato and realised the greatest profits.     

The Status of Selected Minerals in Soil,Forage and Beef Cattle Tissues in a Semi-arid Region of Zimbabwe

Five districts in the Matabeleland region, an arid western area of Zimbabwe, were investigated for the status of Ca, P, Na, Cu and Zn in soil, forage and cattle during the wet and dry seasons over a period of one year. The cattle came from the natural grazing lands and were not supplemented at the time of sampling. Some deficiencies in soil Zn and P were found in the districts of Lupane and Bulilima-mangwe, respectively. Dry season soil Ca, Cu and P concentrations were significantly higher (p < 0.05) than rainy season values owing to leaching in all five districts. Most forage samples had mineral concentrations below the critical levels known to be adequate for animal requirements. Forage levels of Ca, Na, Cu and Zn significantly increased (p < 0.05) with advancing maturity, while P significantly decreased (p < 0.05) in almost all the districts. Marked deficiencies of minerals were found in cattle tissues and these levels followed the seasonal trend seen in the forage. These results indicate that cattle in Matebeleland are deficient in P, Ca, Cu and Zn and that grazing areas in the region cannot provide adequate levels of the five minerals studied.     

Genotype and environmental variation in phenolic content, phenolic acid composition, and antioxidant activity of hard spring wheat

The health-promoting effects of whole-grain wheat likely derive from phenolic compounds and other antioxidants that also make wheat a potential source of functional food ingredients. The objective of this study was to determine the effects of genotype and growing environment on the phenolic contents and antioxidant activities of alcohol-soluble extracts from commercial wheat cultivars. Total phenolic contents (TPCs), antioxidant activities (AOAs), and concentrations of six phenolic acids were measured in six red- and white-grained hard spring wheat genotypes grown at four diverse locations in Western Canada during the 2003 crop year. There were significant differences among genotypes and environments for TPC, AOA, and concentrations of all the phenolic acids measured. The predominant indicators of antioxidant potential, i.e., TPC, AOA, and ferulic acid (FA) concentration were highly intercorrelated (r > 0.72). For these indices, the Canada Western (CW) Red Spring wheat cultivars Neepawa and AC Elsa had the highest levels, whereas an analogous CW hard white spring wheat cultivar, AC Snowbird, had the lowest levels. Grain color did not appear to be a factor in the expression of antioxidant-related parameters. For both TPC and AOA, as well as for vanillic acid, syringic acid, and ferulic acid, environmental effects were considerably larger than genotype effects. Neither growing temperature nor rainfall from anthesis to maturity appeared to be related to the environmental variation that was observed. Genotype x environment interaction was small for all parameters compared with genotype and location effects and was significant only for TPC. Genotype variation for antioxidant properties indicates that it would be possible to select for these quantitative traits in a breeding program. However, the significant environmental variation observed would delay and/or complicate this process.     

Triazine carryover in semi-arid conditions

The persistence of atrazine, prometon and a 1:3 mixture of metolachlor with terbuthylazine was studied under field conditions for 3 years in a semi-arid tropical climate. Each product was applied at recommended and double doses as pre-emergence treatments. The persistence of these herbicides was assessed both by bioassay techniques using crops commonly grown in Zimbabwe and by chemical analysis of the soil. At recommended doses the metolachlor plus terbuthylazine mixture did not cause any crop phytotoxicity in all three seasons whereas at double dosage it caused phytotoxicity in two of the three seasons. Atrazine at recommended doses was slightly phytotoxic in one of the three seasons whereas at double the dose it caused slight injury in two of the three seasons. Prometon caused slight injury in two of the three seasons at both doses. All injury symptoms from these herbicides were soon outgrown and the crop grain yield was not adversely affected. A leaching experiment was also carried out in the laboratory for 2 years using polyvinyl chloride (PVC) pipes. In these experiments atrazine was leached down to 40 cm, with most injury to the tested plants occurring in the top 25 cm of the soil profile. Chemical analysis of the soil revealed that residues of the three herbicides were still found in the soil 12 months after application, but in small amounts which did not cause crop yield reductions.     

Effect of agro-ecological zone,season of birth and sex on pre-weaning performance of Nguni calves in Limpopo Province,South Africa

The study was conducted to determine the effect of agro-ecological zone, season of birth and sex on Nguni calves’ pre-weaning performance. Production indices such as birth weight (BW), weaning weight (WW), pre-weaning average daily gain (P-ADG) and pre-weaning gain (P-WG) were assessed in the different agro-ecological zones. Herd records on performance of 826 Nguni calves’ from nine Nguni herds representing different agro-ecological zones: arid zone (n?=?217); semi-arid zone (n?=?296); dry sub-humid zone (n?=?118) and humid zone (n?=?195) were used for the analysis of pre-weaning calf performance. General linear model (GLM) procedure of SAS (2013) was used to analyse data, whereas mean separation was conducted using Tukey’s HSD test. Agro-ecological zone had a great influence (P?<?0.01) on performance levels arising from pasture conditions which were dependent on rain, temperature, topography and soil type. Fluctuations in WW, P-ADG and P-WG performance across agro-ecological zones depicted the sensitivity of Nguni calves’ to postnatal stress. Calves’ in humid zone had higher performance with 121.21 kg for WW, 96.83 kg for P-WG and 0.477 kg/day for P-ADG. The lowest WW (114.51 kg), P-WG (89.98 kg) and P-ADG (0.438 kg/day) were observed in arid zone. Male calves were heavier at weaning (128.18 kg), P-ADG (0.503 kg/day) and total gain (103.03 kg); however, similar BW of 25 kg was observed for both male and female calves. Season had a significant (P?<?0.05) effect on BW, P-ADG and P-WG. The P-ADG was 0.461 kg/day for calves born in summer and 0.449 kg/day for calves born in winter season. Calves born in summer gained 94.69 kg and calves born in winter gained 92.10 kg. Summer calves gained 2.59 kg more than winter calves. Summer heifer calves performed poorly whilst summer male calves outperformed heifer calves in terms of WW, P-WG and P-ADG. Pre-weaned calves in humid zone outperformed all calves in other agro-ecological zones. It was concluded that acceptable levels of growth are achievable from Nguni cattle under the different agro-ecological zones of Limpopo province, South Africa.