Modelling the Effect of Climate Change on Environmental Pollution Losses from Dairy Systems in the UK

21 p.So far, there has been strong emphasis on studying the impacts of climate change on agriculture in terms of changes in food production; however, there is increasing evidence that agricultural ecosystems (e.g. livestock) will also be severely affected in terms of other goods and services. For example, patterns and loads of environmental pollution derived from nutrient losses are expected to change dramatically (e.g. increased run-off: Betts et al., 2007). There have been few studies that use a system-based approach to explore the complex interactions between farm inputs, response of system components and inherent site factors that give rise to changes in productivity, environmental pollution losses and agricultural services in future scenarios. This article describes the methodology and the results of a study to evaluate the effect of climate change only on losses of nitrogen (N) and carbon (C) from grassland-based livestock systems in 10 UK Regional Development Programme (RDP) areas. In order to do so, a modelling framework integrating different models at the crop and farm level was developed and implemented. Simulated projections suggest that farming systems will undergo different changes in food production and associated nutrient losses depending on different areas and time-slices. Potential trade-offs on other pillars of farm sustainability (e.g. net farm income, biodiversity and soil quality) were simulated and illustrated as an example

Measuring motivation for appetitive behaviour: food-restricted broiler breeder chickens cross a water barrier to forage in an area of wood shavings without food

Broiler breeders (parents of meat chickens) are selected for fast growth and become obese if fed ad libitum. To avoid this and maintain good health and reproductive ability, they are feed restricted to about 1/3 of what they would eat ad libitum. As a result, they experience chronic hunger and exhibit abnormal behaviour patterns that may indicate stress and frustration. One approach to measuring hunger is to observe how much birds will work, such as pecking a key, for access to more or different types of food. However, the sight, smell, and feedback from consumption of the feed reward changes the context and may artificially raise feeding motivation. To avoid this, we tested broiler breeders in an apparatus in which they could work for access to a wooden platform covered in wood shavings by crossing a water runway which increased in length and depth in 8 successive tests. In the wood shavings area, they could perform exploratory and foraging behaviour (the appetitive phase of feeding) but were never rewarded with feed. Sixty birds were divided into three feed quantity treatments: commercial restriction (R), and twice (2R) or three times (3R) this amount. Overall, birds fed R worked harder to reach the wood shavings area (reached it in a larger number of tests) than 2R and 3R birds (P2R>3R). This indicates that restricted-fed birds were hungry and willing to work for the opportunity to forage even though food was never provided, suggesting that their motivation to perform the appetitive component of feeding behaviour (foraging/food searching) was sufficient to sustain their response. Thus food restriction in broiler breeders is a welfare concern. However these methods could be used to test alternative feeding regimes to attempt to find ways of alleviating hunger while still maintaining healthy growth and reproduction in these birds

Quantifying hungry broiler breeder dietary preferences using a closed economy T-maze task

This study aimed to identify hungry broiler breeders (n = 12) preferences for quantitative (control) or qualitative dietary restriction (QDR) in a closed economy environment. The QDR option was either 3 g calcium propionate/kg total feed (n = 6) or 300 g oat hulls/kg total feed (n = 6). Quantitatively restricted or QDR portions ensured equal growth regardless of choice. Birds were separately taught a Control diet versus no food and a QDR diet versus no food task to allow each diet's satiating properties to be learnt. Birds had to associate the T-maze coloured arms with dietary outcomes to immediately obtain food. Birds learnt this task easily (p < 0.001). A choice between the control diet and the QDR diet was then offered but neither group demonstrated a diet preference. Study modifications demonstrated this was not a failure to discriminate between the diets per se (the Control diet was strongly preferred under ad libitum conditions (p < 0.001)) or novel colour combination confusion (the colour associated with food was immediately selected when two novel food versus no food colour combinations were offered (p < 0.001)). Most birds still failed to show a significant preference when the Control diet quantity was increased by 50% to make it ‘obviously’ bigger and better. Therefore, it was concluded that the failure to show a dietary preference was due to task learning failure and not necessarily lack of dietary preference. Where a preference was observed it was always for the control diet. Possible reasons for this failure to learn are discussed

Modelling the Effect of Climate Change on Environmental Pollution Losses from Dairy Systems in the UK

21 p.So far, there has been strong emphasis on studying the impacts of climate change on agriculture in terms of changes in food production; however, there is increasing evidence that agricultural ecosystems (e.g. livestock) will also be severely affected in terms of other goods and services. For example, patterns and loads of environmental pollution derived from nutrient losses are expected to change dramatically (e.g. increased run-off: Betts et al., 2007). There have been few studies that use a system-based approach to explore the complex interactions between farm inputs, response of system components and inherent site factors that give rise to changes in productivity, environmental pollution losses and agricultural services in future scenarios. This article describes the methodology and the results of a study to evaluate the effect of climate change only on losses of nitrogen (N) and carbon (C) from grassland-based livestock systems in 10 UK Regional Development Programme (RDP) areas. In order to do so, a modelling framework integrating different models at the crop and farm level was developed and implemented. Simulated projections suggest that farming systems will undergo different changes in food production and associated nutrient losses depending on different areas and time-slices. Potential trade-offs on other pillars of farm sustainability (e.g. net farm income, biodiversity and soil quality) were simulated and illustrated as an example

Nutritional sensitivity of periparturient resistance to nematode parasites in two breeds of sheep with different nutrient demands

The periparturient relaxation of immunity (PPRI) to parasites in mammals is sensitive to both metabolisable protein (MP) supply and animal genotype (different reproductive outputs). We tested the hypothesis that the sensitivity of PPRI to MP scarcity would not differ between different levels of reproductive output when nutrient intake is adjusted for associated differences in MP demand; this hypothesis assumes that PPRI has a nutritional basis only. Scottish Blackface (BF) and the more productive Mule (MU) ewes were infected with the abomasal parasite Teladorsagia circumcincta, and from day-(21) to day(32) (day(0) is parturition), they were fed restrictedly at either 0.8 (low protein (LP)) or 1.3 (high protein (HP)) times their breed-specific estimated MP requirement (n 18 for each breed-feeding treatment combination). During late pregnancy, LP feeding reduced ewe body weight gain in both breeds, tended to increase faecal egg count (FEC), but it did not affect plasma pepsinogen. During lactation, LP feeding reduced litter growth rate and ewe plasma urea and plasma albumin concentrations compared with HP feeding in both breeds. However, breed and feeding treatment interacted for ewe FEC, worm egg excretion and plasma pepsinogen, which were higher for the LP-MU ewes compared with the HP-MU and BF ewes. The lower degree of PPRI of the BF ewes during lactation compared with the MU ewes at a similar degree of MP scarcity suggests that the effect of reproductive output on nutritional sensitivity of PPRI cannot be explained by associated differences in nutrient demand only