Foraging behaviour, nutrient intake from pasture and performance of free-range growing pigs in relation to feed CP level in two organic cropping systems

Husbandry practices associated with extensification in European pig production and their effects on pork quality

This review has been developed as part of the mEATquality project with the main objective to examine the types of extensification practices used in European pig husbandry and their effect on intrinsic meat quality. Literature search has resulted in 679 references in total, from which 53 showed a strict compliance with the goals of this review: 1) the use of local European breeds and their crossbreds (22 papers); 2) addition of forage to diet (9 papers); 3) increased space allowance (3 papers); 4) enrichment of environment (19 papers). The evaluation of selected extensification factors showed that not all of them have a clear impact on meat quality, and are often confounded. The most clear differences were observed when comparing autochthonous with commercial breeds, and systems with access to pastures or woodlands vs. indoor housing. Despite many studies focusing on the extensification of husbandry practices, some of the factors cannot be confirmed to have a direct effect on pork intrinsic quality.

Soil ingestion, a key determinant of exposure to environmental contaminants. The case study of chlordecone exposure in free-range pigs in the French West Indies

Ingested soil may expose free-range animals to environmental pollutants. In pigs, soil ingestion is few described whereas their burrowing behaviour suggests that it could be high. Although highly productive pigs are generally reared indoor, free-range farming is increasing in view of ethical considerations for animal welfare and is a common practice for subsistence agriculture systems. The experiment lasted 8 weeks (2 for adaptation, 6 for measurements) with 24 growing pigs of Guadeloupean Creole (CR) or Large White (LW) breeds. Pigs were assigned to 3 outdoor treatments: high pasture HP (>60 days of regrowth), low pasture LP (35 days of regrowth), and sweet potato SP (sweet potato field). Titanium (soil marker) and chromium (faecal output marker) contents of faeces, vegetation and soil samples were used to estimate individual daily soil ingestions. The average, 10th and 90th percentiles were 440, 200 and 726 g of dry soil per 100 kg body weight, respectively, without significant differences between the 3 outdoor treatments or the 2 breeds but with a significant period (i.e. week of measurements) × treatment interaction (P < 0.001). In the French West Indies, animals may be exposed to chlordecone (CLD), a very persistent organochlorine insecticide. Simulations of CLD tissue contamination due to ingestion of contaminated soil were carried out and compared to the maximum residue limit. These results show that grazing management needs to be adapted to effectively limit soil ingestion by pigs and the impact of a contaminated environment on the sustainability of pig systems.

A Comparison of Stocking Methods for Pasture-Based Growing-Finishing Pig Production Systems

Simple Summary

A sustainable pasture-based production system should provide benefits to the vegetation, soil and animals while providing means of economic support for the household that operates the system. If best management practices are implemented, this would allow the development of resilience for the pasture system and ameliorate the natural resources for present and future generations. Pasture-based pig production represents a production alternative for small scale or limited-resources farmers, offering them the possibility to brand their products. The implementation of best management practices would allow managers to reach productive and conservation goals. This study was conducted to compare the effects of continuous, rotational and strip-grazing stocking methods for growing-finishing pigs on tall fescue pastures. Stocking methods had effect on soil bulk density and some soil nutrients, vegetative ground cover, animal weight gain and feed use efficiency. The rotational and strip grazing stocking methods offer potential to improve the sustainability of pasture-based pig systems.

Abstract

Two alternative stocking methods (rotational and strip-grazing) were compared to continuous stocking at a stocking rate of 47 pigs ha⁻¹ in tall fescue pastures. The research was conducted during two twelve-weeks grazing periods in North Carolina (USA). In total 144 (females and castrated males, 17.5 and 29.1 kg initial body weight) crossbred Yorkshire X Berkshire, Yorkshire/Landrace X Hampshire and Yorkshire/Landrace X Duroc pigs without nose rings were used. Greater soil bulk density and soil concentrations of NO₃⁻, P, K, Mn, Zn and Cu were observed in paddocks managed continuously, while greater final ground cover (+22%) was recorded in paddocks managed with rotational and strip-grazing stocking methods. No differences were detected in botanical composition of the paddocks. Greater weight gains (+8.5%) were registered for rotationally managed pigs. Feed efficiency was better (+8%) for rotationally than for continuously stocked pigs, while strip-grazed pigs presented intermediate values. The results indicated the potential of both alternative stocking methods to be implemented in sustainable pasture-based pig production systems.

Forage Consumption and Its Effects on the Performance of Growing Swine-Discussed in Relation to European Wild Boar (Sus scrofa L.) in Semi-Extensive Systems: A Review

Simple Summary

Outdoor-reared European wild boar (Sus Scrofa L.) is regarded as a delicacy by consumers due to its favourable meat properties and an association with high welfare standards. The rearing of wild boar on pasture has the potential to minimise input costs relative to conventional production systems. However, some pasture production systems have been found to perform poorly due to low growth rates. This review collates the available scientific evidence on pasture-based production of wild boar and domestic pigs, to identify factors that influence feed intake, performance, and behaviour. Factors explored include season/weather, dietary supplementation, grazing management, forage availability, herbage quality, and sward type. For example, the additional feed availability associated with pasture grazing has been shown to be a significant factor that positively correlates with dry matter intake of wild boar. This has been demonstrated to result in better feed conversion efficiency and reduced feed costs without reductions in growth rates compared to animals without access to pasture. Furthermore, the increased availability of favoured species in pasture may also promote dry matter intake. The long-term sustainability of wild boar production is dependent on the economic, social, and environmental viability of the systems. Pasture-based production systems may be one way by which this can be achieved, but only if implemented correctly.

Abstract

Due to its distinct properties, wild boar meat is considered a highly desirable consumer product, in a market that is expanding. Outdoor production is also favoured by consumers who value animal welfare and environmental sustainability when choosing meat products. There is evidence that farms that include pasture for grazing typically have reduced feeding costs. Such production systems can also be more environmentally sustainable as the input (pasture) is inedible to humans, compared to conventional indoor systems, which use human-edible feeds (e.g., soya). However, some wild boar farms have performed poorly compared to those rearing other swine such as hybrid wild boar and domestic pigs. Diet is central to all livestock production and is likely a significant influencing factor of wild boar performance, both in terms of forage consumption and nutritional composition. Other factors may also influence performance, such as weather, behaviour and grazing management. Wild boar production systems hold their own intrinsic value in a growing marketplace. However, information gathered through the study of wild boar has external applications in informing outdoor domestic pig production systems to encourage the use of pasture as part of the habitat of domestic pigs.

Increased Foraging in Outdoor Organic Pig Production-Modeling Environmental Consequences

Consumers’ motivations for buying organic products include a wish of acquiring healthy, environmentally friendly products from production systems that also ensure a high level of animal welfare. However, the current Danish organic pig production faces important challenges regarding environmental impact of the system. High ammonia emissions arise from outdoor concrete areas with growing-finishing pigs and sows on pasture possess an increased risk of nitrogen (N) leaching. Direct foraging in the range area is suggested as a way to improve the nutrient efficiency at farm level and to support a more natural behavior of the pig. Thus, by modeling, we investigated the environmental consequences of two alternative scenarios with growing-finishing pigs foraging in the range area and different levels of crops available for foraging; grass-clover (lowest integration of forage) or a combination of lucerne, grass-clover and Jerusalem artichokes (highest integration of forage). It was possible to have growing-finishing pigs on free-range without increasing N leaching compared to the current practice. The alternative system with lucerne, grass-clover and Jerusalem artichokes showed the lowest carbon footprint with 3.12 CO₂ eq kg⁻¹ live weight pig compared to the current Danish pasture based system with 3.69 kg CO₂ eq kg⁻¹ live weight pig. Due to positive impact on soil carbon sequestration, the second alternative system based on grass-clover  showed a similar carbon foot print compared to current practice with 3.68 kg CO₂ eq kg⁻¹ live weight pig. It is concluded that in practice there is room for development of organic pig production systems where direct foraging plays a central role.