Spatio-Temporal Patterns of Predator–Prey Model with Allee Effect and Constant Stocking Rate for Predator

A diffusive predator–prey model with Allee effect and constant stocking rate for predator is investigated and it is shown that Allee effect is the decisive factor driving the formation of Turing pattern. Furthermore, it is observed that Turing pattern appears only when the diffusion rate of the prey is faster than that of the predator, which is just opposite to the condition of Turing pattern in the classical predator–prey system. Some sufficient conditions are obtained to ensure the asymptotical stability of a spatially homogeneous steady-state solution. The existence and nonexistence of positive nonconstant steady-state solutions are investigated to understand the mechanisms of generating spatiotemporal patterns. Furthermore, Hopf and steady-state bifurcations are analyzed in detail by using Lyapunov–Schmidt reduction.

Stocking rate of extensive land-reform livestock farmers during 2018/2019 drought: Bloemfontein grassland biome case study

The study aimed to determine the average stocking rate among land reform beneficiary farmers specialising in livestock production in order to establish differences between calving percentage, fodder availability, and mortality rate of sampled farms, as well as to compare forage scarcities of Land Reform farms with their neighbouring farms during the midsummer drought of 2018/2019 in the Bloemfontein area. The average stocking rate was 5.9 ha/LSU in comparison with the Departmental grazing capacity norm of 6 ha/LSU for rangeland in good condition. However, 31% of the sampled farms were found to be severely overstocked, and the mortality rate on these farms, in relation to grazing capacity of 6 ha/LSU, was significantly higher (P < 0.05) than the mortalities on the other remaining farms. Naturally available fodder was found to be heterogeneous, with 37.9% of the respondents observing their available fodder as worse than that of their neighbours. The total mortality of 176.77 LSUs was recorded for the 29 sampled farms. These findings will assist the local extension personnel prevent future rangeland condition degradation and increase land reform farmers’ productivity. The study concluded that training is paramount to farmers’ development and further recommends more research undertakings.

Quail husbandry and welfare systems at Songhai-Delta farm: Profitability of enterprise

Quails are small sized pheasants having a long history of domestication and utilization. The management and welfare systems of Quail production at Songhai Delta farm were surveyed and reviewed. The young quails were sexed by the feather and vent methods when at 6 weeks old and they begin to lay eggs at about that age. Fertile eggs are managed in hatchery until chicks are hatched. Other set of eggs laid are also collected and sold in the farm shop. The quails were fed three types of ration - starter mash at 1-4 weeks of age, grower mash 4-6 weeks and layer mash as from 6 weeks of age. Quails are susceptible to some common poultry diseases; but good management and welfare practices ensure safety and healthy birds. A ratio of 1male to 3 females is the stocking rate in breeder cages in the farm, to obtain fertile eggs. High feed cost and poor market for farm products were the most significant problems of the enterprise. The cost and return estimate for quail bird production indicate that quail venture is highly profitable. The bird has early sexual maturity resulting in a short generation intervals and high rate of lay. Thus, raising quail offers many advantages when compared to producing other domestic or food animals. Quail venture is excellent and recommended for beginners in poultry business, because the birds begin to lay eggs at young age of about 6weeks; and can be slaughtered for food at 5weeks of age. Many developing countries presently faced with problem of inadequate supply of animal protein should find quail production a viable industry. The study recommends a step up of extension services to enlighten farmers and the populace on the importance of quail meat and eggs and the profitability of quail farming. Les cailles sont de petite taille ayant une longue histoire de domestication et d'utilisation. Les systèmes de gestion et de bien-être de la production de cailles à la ferme du delta de Songhai ont été considéré et examinés. Les jeunes cailles sont sexées par les méthodes de 'feather and vent' lorsqu'elles ont 6 semaines et qu'elles commencent à pondre des œufs vers cet âge. Les œufs fertiles sont gérés dans l'écloserie jusqu'à ce que les poussins soient éclos. D'autres œufs pondus sont également recueillis et vendus dans la boutique de la ferme. Les cailles ont été nourries de trois types de ration - purée de démarrage à l'âge de 1-4 semaines, purée de grower 4-6 semaines et purée de couche à partir de 6 semaines d'âge. Les cailles sont sensibles à certaines maladies courantes de la volaille ; mais de bonnes pratiques de gestion et de bien-être assurent la sécurité et la santé des oiseaux. Un rapport de 1male à 3 femelles est le taux de stockage dans les cages d'élevage dans la ferme, pour obtenir des oeufs fertiles. Le coût élevé des aliments pour animaux et le mauvais marché des produits agricoles ont étéles problèmes les plus importants de l'entreprise. L'estimation du coût et du rendement de la production d'oiseaux caille indique que l'entreprise de cailles est très rentable. L'oiseau a une maturité sexuelle précoce résultant en un intervalle de génération court et un taux élevé de produire des oeufs. Ainsi, l'élevage de cailles offre de nombreux avantages par rapport à la production d'autres animaux domestiques ou alimentaires. L'entreprise de caille est excellente et recommandée pour les débutants dans le secteur de la volaille, parce que les oiseaux commencent à pondre des œufs à un jeune âge d'environ 6 semaines ; et peut être abattu pour la nourriture à l'âge de 5 semaines. De nombreux pays en voie du développement confrontés à un problème d'approvisionnement insuffisant en protéines animales devraient trouver la production de cailles une industrie viable. L'étude recommande une augmentation des services d'extension pour éclairer les agriculteurs et la population sur l'importance de la viande et des œufs de caille et la rentabilité de l'élevage de cailles.

Effects of Livestock Grazing on Interannual Variation of Soil Methane Uptake in an Inner Mongolian Meadow Steppe

Background and aims. This study aimed at identifying the effects of livestock grazing on interannual variation in soil CH4 uptake and underlying mechanisms in a meadow steppe ecosystem. Methods. A multi-year grazing experiment subject to six stocking rates was conducted to quantify CH4 fluxes as well as the changes in driving factors: vegetation traits, soil physicochemical properties and climatic parameters. The closed static chamber technique and a gas chromatograph were used to measure methane fluxes. Multivariate regression analysis was performed to explore empirical relationships. Results. With increasing stocking rate, the multi-year mean CH4 uptake rate decreased in a sigmoid curve-shaped manner, with the threshold point appearing in the light grazing treatment. The interannual changes in soil CH4 uptake were highly dependent on stocking rate, with increasing, leveling and decreasing trends detected with increasing grazing intensity. Major factors affecting CH4 fluxes included vegetation traits, soil moisture, and soil nitrogen content, with the soil NH4+-N content assuming the most important role. However, predominant factors regulating interannual changes in CH4 uptake were rainfall, belowground biomass, and soil nitrogen regime. Conclusions. The steppe ecosystem acted as a CH4 sink, irrespective of stocking rate and year. However, light grazing can be the threshold grazing intensity in terms of both the CH4 uptake potential and primary production in this steppe ecosystem. Our findings have important implications for further understanding magnitudes and regulations of CH4 uptake in grassland soils worldwide.

Production Characteristics of Ryegrass Pasture under Different Intensities of Grazing and Nitrogen Fertilization in Integrated Crop-livestock Systems

Background: There is little information on the effect of interaction between grazing intensity and nitrogen fertilization on the productive characteristics of ryegrass (Lolium multiflorum Lam). The objective of this work was to evaluate the effect of grazing intensity and nitrogen fertilization on the productive characteristics of ryegrass pasture in a crop-livestock integration system. Methods: A randomized complete block experimental design with a 2 × 2 × 5 factorial arrangement was used, with three replications. The study factors were two management grass heights, low height (LH = 10 cm) and high height (HH = 25 cm), two different nitrogen fertilization times (NP = nitrogen applied to pasture and NG = nitrogen applied to grains crop) and five evaluation periods. Result: The forage mass was higher at higher handling heights and with lower stocking rate (HH = 3995 kg DM ha-1). The forage density tended to be higher in the plots with lower grass height and nitrogen fertilization (LH = 193.5 and NP = 184.7 kg DM ha-1 cm-1). The highest accumulation rate (AR) and forage production (FP) was observed in managed pastures with HHNP (AR = 120.4 kg DM ha-1 day-1; FP = 18471 kg DM ha-1). The management of grass with HHNP provided higher forage mass, higher accumulation rate and higher dry matter production in ryegrass pasture, due to an adequate stocking rate.

Ewe performance in the post-weaning phase and structural characteristics of Brachiaria brizantha cultivars in the dry season

The objective of this study was to examine the performance of ewes in the post-weaning phase and the structural characteristics of Brachiaria brizantha cultivars in the dry season. The treatments were represented by four Brachiaria brizantha cultivars (Piatã, Marandu, Paiaguás, and Xaraés), which were evaluated in a randomized-block design with two replicates for the forage variables and eight replicates for the animal performance variables. Canopy height, masses of forage and morphological components and chemical composition of morphological components were evaluated. Thirty-two ½ Santa Inês and ½ Dorper sheep with an initial body weight (BW) of 22.7 ± 1.2 kg were used. Average daily gain (ADG – kg animal-1 day-1), stocking rate (in animal units [AU] = 30 kg of body weight) and weight gain per area (kg ha-1 day-1) were measured. There was no cultivar effect (p > 0.05) on the structural characteristics of the pasture. The highest crude protein content in the leaf blade (11.8%) were found in cultivar Marandu. Average daily gain was higher in the animals that grazed on cultivar Marandu (0.08 kg animal-1 day-1) as compared with cultivars Xaraés (0.05 kg animal-1 day-1) and Piatã (0.04 kg animal-1 day-1), whereas the ewes that grazed on cultivar Paiaguás showed intermediate ADG values (0.06 kg animal-1 day-1). There was no difference between the cultivars for stocking rate (9.2 AU). Weight gain per area was highest in cultivar Marandu (0.33 kg ha-1 day-1) and lowest in cv. Piatã (0.16 kg ha-1 day-1). Brachiaria brizantha cultivars Piatã, Marandu, Paiaguás and Xaraés proved to be forage options for the post-weaning phase of ewes supplemented with concentrate in the dry season.

PSXIII-15 Impact of forage allowance on performance and reproductive parameters in Nellore heifers

The objective was to evaluate the effects of forage allowance on the performance and pregnancy rate of Nellore heifers submitted to the fixed-time artificial insemination (FTAI) at 14±1 months. The experimental period was divided into the growing phase (GP; 173d) and breeding season (83d). Ninety weaned Nellore heifers [169±19 kg of body weight (BW); 210±28 days of age] were blocked by initial BW and randomly assigned to receive different forage allowance: (1) High (HFA; 7.17 kgDM/kgBW; and (2) Low (LFA; 3.27 kgDM/kgBW); and divided into 6 paddocks (2.15 to 2.4 ha each one). The grazing method used was continuous stocking with a variable stocking rate where treatment conditions were established varying the stocking rate on pasture (put-and-take). The supplement consisted of corn, soybean meal, urea, monensin, sodium chloride and minerals mix (80% TDN and 24% CP) and was provided daily (ad libitum; expected intake around 1% of BW). The final pregnancy rate was determined after two FTAI (d256). Heifers BW at the end of the GP was greater (P &lt; 0.01) for HFA vs. LFA (268 vs. 255 kg). The overall average daily gain (ADG) was greater 68 g/d for animals maintained in HFA than LFA (P &lt; 0.01; 0.713 vs. 0.645 kg/d). Supplement intake (kg/animal/d) had no treatment effect (P = 0.117). On d173, forage allowance affected (P &lt; 0.01) the backfat thickness obtained by real-time carcass ultrasound (HFA = 3.08 vs. LFA = 2.85 mm). The pregnancy rate had no treatment effect (P = 0.223; on average 61%). However, the pregnant heifers per hectare had treatment effect (P = 0.036; HFA = 3.78 vs. LFA = 2.72 pregnant heifers/ha). In conclusion, the low forage allowance reduces the animal performance and affects the carcass composition but provides a greater number of pregnant heifers per hectare.

PSIII-7 Seasonal effects on nutritional value of Oklahoma prairie grass when grazed in extensive or intensive systems

The objectives of this study were to determine the effects of sampling month and grazing system on tallgrass prairie forage nutritive value. Native tallgrass prairie pastures (n = 6) were assigned to either an extensive (EXT) or intensive (INT) grazing system for 5 consecutive years. Extensive system pasture annual stocking rate was 6.1 hectares per cow-calf pair with cows remaining in their respective pastures year-round. Intensive system pasture annual stocking rate was 3.0 hectares per cow-calf pair with cows present in the pastures 160 days per year [mid-May through mid-July (58 ± 6 d) and mid-September through mid-December (102 ± 4 d)]. Forage samples were collected monthly from two to four locations within each pasture. Samples were dried, separated into subsamples of leaf material and whole plant matter, ground, and analyzed using near-infrared spectroscopy. Data were analyzed using a mixed model (SAS 9.4) with grazing system, month, sample type (leaf or whole), and all two-way interactions as fixed effects and year as a random effect. Forage crude protein (CP) was not different between leaf or whole plant samples (P = 0.97) and increased (P &lt; 0.001) in May (10.8% CP), declined in the fall, and stayed low (2 – 4% CP) in both systems. Neutral detergent fiber (NDF) was greater during May to July (P = 0.040) in the EXT than the INT pastures. Acid detergent fiber (ADF) differed by month (P &lt; 0.001) and was lowest between April and May. In vitro true dry matter digestibility (IVTDMD) was greater in INT (63.7%) than EXT (62.3%) pastures regardless of month (P &lt; 0.001), and both systems were greater during May through August (65 – 75%; P &lt; 0.001) than the winter months (56 – 60%). These data indicate that protein supplementation is likely required outside of May and June, especially for lactating cows.