Estimation of genetic parameters for reproductive traits in shall sheep

The objective of this study was to estimate genetic parameters for reproductive traits in Shall sheep. Data included 1,316 records on reproductive performances of 395 Shall ewes from 41 sires and 136 dams which were collected from 2001 to 2007 in Shall breeding station in Qazvin province at the Northwest of Iran. Studied traits were litter size at birth (LSB), litter size at weaning (LSW), litter mean weight per lamb born (LMWLB), litter mean weight per lamb weaned (LMWLW), total litter weight at birth (TLWB), and total litter weight at weaning (TLWW). Test of significance to include fixed effects in the statistical model was performed using the general linear model procedure of SAS. The effects of lambing year and ewe age at lambing were significant (P?<?0.05). Genetic parameters were estimated using restricted maximum likelihood procedure, under repeatability animal models. Direct heritability estimates were 0.02, 0.01, 0.47, 0.40, 0.15, and 0.03 for LSB, LSW, LMWLB, LMWLW, TLWB, and TLWW, respectively, and corresponding repeatabilities were 0.02, 0.01, 0.73, 0.41, 0.27, and 0.03. Genetic correlation estimates between traits ranged from ?0.99 for LSW–LMWLW to 0.99 for LSB–TLWB, LSW–TLWB, and LSW–TLWW. Phenotypic correlations ranged from ?0.71 for LSB–LMWLW to 0.98 for LSB–TLWW and environmental correlations ranged from ?0.89 for LSB–LMWLW to 0.99 for LSB–TLWW. Results showed that the highest heritability estimates were for LMWLB and LMWLW suggesting that direct selection based on these traits could be effective. Also, strong positive genetic correlations of LMWLB and LMWLW with other traits may improve meat production efficiency in Shall sheep.     

Effects of age and host availability on reproduction of <Emphasis Type="Italic">Trioxys angelicae</Emphasis> Haliday (Hymenoptera: Braconidae) parasitizing <Emphasis Type="Italic">Aphis fabae</Emphasis> Scopoli (Hemiptera: Aphididae)

Laboratory studies were conducted to determine the effects of Trioxys angelicae Haliday (Hym.: Braconidae) age and host density (Aphis fabae Scopoli) (Hem.: Aphididae) on selected attributes of parasitoid reproductive biology. The number of hosts parasitized per day was used as an estimate of wasp fecundity. Parasitoid longevity was not affected by host density and at host densities of 2, 4, 6, 8, 10, 15, 20, 30, 40 or 60 aphids per day; the parasitoids lived an average of 8.96 ± 0.82 days at 21°C. At host densities of ≤20 aphids per day, lifetime fecundity of a single Trioxys angelicae female was limited by the number of hosts available. Lifetime fecundity was highest with an average of 158.14 ± 20.33 at a density of 30 aphids per day; the maximum number of aphids parasitized by any female was 235. Daily fecundity and sex ratio were affected by parasitoid age and host density. Age-specific fecundity at different host densities fitted well to a nonlinear model. In conclusion, the fecundity and female progeny production of Trioxys angelicae as an important biological control agent of A. fabae is influenced by host availability.     

Effect of plant secondary metabolites on legume pod borer, Helicoverpa armigera

The effect of various flavonoids, lectins and phenyl β-d-glucoside on larval survival, weights and the activities of digestive (total serine protease and trypsin) and detoxifying [esterase and glutathione-S-transferase] enzymes of Helicoverpa armigera larvae at 5 and 10 days after treatment (DAT) was studied through diet incorporation assay. Flavonoids (quercetin, cinnamic acid, caffeic acid, chlorogenic acid, catechin, trihydroxyflavone, gentisic acid, ferulic acid, protocatechuic acid and umbelliferone) were incorporated in artificial diet at 100, 500 and 1000 ppm, lectins: groundnut leaf lectin (GLL), concavalin (ConA) and phenyl β-d-glucoside at 2.5 and 5 μg mL^?1. Flavonoids such as chlorogenic acid, caffeic acid and protocatechuic acid at 1,000 ppm were more toxic to H. armigera larvae at 10 DAT than quercetin, catechin, cinnamic acid, trihydroxyflavone, gentisic acid, ferulic acid and umbelliferone. Larval growth and development were significantly reduced in H. armigera larvae fed on a diet with GLL and ConA at 5 μg mL^?1 compared to the larvae fed at 2.5 and 1.25 μg mL^?1 concentrations. The enzyme activities of the larvae were significantly reduced in flavonoid-treated diets. The flavonoids such as chlorogenic acid, caffeic acid, gentisic acid, trihydroxyflavone, catechin and protocatechuic acid, and lectins, GLL and ConA can be utilized in insect control programs.     

Economic values and selection indices for production and reproduction traits of Iranian buffaloes (Bubalus bubalis)

Tropical Animal Health and Production - Iranian buffalo plays a critical role in supplying a portion of the income and the necessities of the rural population. The first step to design a breeding...     

Modern sediment records of hydroclimatic extremes and associated potential contaminant mobilization in semi-arid environments: lessons learnt from recent flood-drought cycles in southern Botswana

Journal of Soils and Sediments - The aim of this work was to identify and analyze the records of flood-drought cycles as preserved in the sediments of the Notwane reservoir, southern Botswana, in...     

The side-effects of pesticides onDiaeretiella rapae, a parasitoid of the turnip aphid (Lipaphis erysimi)

Diaeretiella rapae (M’Intosh.) is an endoparasite of the turnip aphid,Lipaphis erysimi (Kalt.) with a wide geographical distribution. The four Pesticides Nogos 50 EC at 600 ml per acre, Dimecron 50 WSC, Monofos 40 WSC and Tamaron 600 SL at 500 ml per acre, used in practice for the control of this pest, were tested for their side-effects onD. rapae. The parasitoid was reared on pottedBrassica napus plants infested with aphid under laboratory conditions (22±2°C, 60–70% rel. hum., 16 h light and 8 h dark). In one test, adult female parasitoids were exposed to fresh pesticide residues on glass plates and in another test, the pupae within aphid mummies were directly sprayed. The results revealed that Dimecron 50 WSC, Nogos 50 EC and Monofos 40 WSC were harmful causing 100% mortalitv toD. rapae followed by Tamaron 600 SL (97% moderately harmful) after 24 hours of application, compared to no mortality in control, where only water was sprayed. Directly spraying of pupae with Dimecron 50 WSC and Nogos 50 EC reduced adult parasitoid emergence to 9 and 7%, respectively, Monofos 40 WSC and Tamaron 600 SL to 3% compared to 78% emergence for the control within one week of treatment. The results showed that none of the tested pesticides was safe toD. rapae and according to the International Organization for Biological Control (IOBC) further testing under semi-field and field conditions is recommended.