Sustainable intensification? Increased production diminishes omega-3 content of sheep milk

Intensifying agricultural production alters food composition, but this is often ignored when assessing system sustainability, yet it could compromise consumers’ health and the concept of ‘sustainable diets’. Here we consider milk composition from Mediterranean dairy sheep, finding inferior fatty acid (FA) profiles with respect to consumer health as a result of a more intensive system of production. Semi-intensive management did produce 57% more milk per ewe with 20% lower fat content, but inferior fat composition. Milk had a nutritionally poorer fatty acid (FA) profile, with 18% less omega-3 FA (n-3) (19% less long-chain n-3) and 7% less monounsaturated FA but 3% more saturated FA (9% higher in C14:0) concentrations compared with ewes under traditional, extensive management. Redundancy analysis identified close associations between fat composition and animal diets, particularly concentrate supplementation and grazing cultivated pasture - n-3 was associated with grazing diverse, native mountain pastures. The paper questions if identifying such key elements in traditional systems could be deployed for ‘sustainable intensification’ to maintain food quality whilst increasing output

Effect of intensification practices, lambing period and environmental parameters on animal health, and milk yield and quality in dairy sheep production systems on Crete

Due to increasing demand, many traditional, grazing-based Mediterranean sheep production systems have introduced intensified feeding regimes, increased investments in facilities and equipment (milking machines) and modified their veterinary regimes to increase milk yields. However, compared to bovine milk production systems, there is limited knowledge about the impact of these intensification practices on animal welfare/health and on the quality of dairy products. The aim of this study was therefore to quantify the effects of production intensity/feeding regimes, lambing period and environmental background conditions on udder health parameters, gastrointestinal nematode infection levels and milk yield and quality parameters in traditional Sfakiano sheep production systems in Crete. Milk yields were higher in semi-intensive production systems while concentrations of several nutritionally desirable compounds such as omega-3 fatty acids were found to be higher in milk from extensive systems. Antibiotic and anthelmintic use was relatively low in both extensive and semi-intensive production systems there was no substantial difference in faecal egg counts, somatic cell counts (a marker for subclinical mastitis) and mi-cro-biological parameters assessed in milk. Recording of flock health parameters showed that animal health/welfare was high in both extensive and semi-intensively managed flocks, and that overall, the health status of extensively managed ewes was slightly better. In contrast, environ-mental conditions (temperature and rainfall) had a substantial effect on nematode infection levels and milk quality parameters assessed

Effect of abiotic and biotic factors on subclinical mastitis occurrence in low-input dairy sheep production systems

This study aimed to explore the effect of abiotic [microclimate, management (MS) and milking system (MLS)] and biotic risk factors (microorganism group, age class of ewes, lactation month and ewe genotype) on the occurrence of subclinical mastitis in low-input dairy sheep farms. Samplings were carried out in 10 extensively and 10 semi-intensively managed low-input dairy sheep farms, with three milking systems: milking parlour machine (MPM), portable milking machine (PM) and hand milking (HM). Over two consecutive lactations, milk samples (n = 9624) were collected monthly in each farm, from 20 ewes (10 primi- and 10 multi-parous ewes). The ovine major histocompatibility complex (MHC) DQA2 gene was genotyped for all sampled ewes (n = 800). Ambient air temperature and relative humidity were recorded hourly at each farm, in order to calculate the temperature-humidity index (THI) affecting each sampled sheep. Daily milk yield (DMY) per ewe, pH, total bacterial count (TBC) and somatic cell count (SCC) of milk samples were measured. The fixed effects of microclimate, MS, MLS, bacterial pathogen (microorganism group), age class of ewes, lactation month, involved in milk SCC and subclinical mastitis occurrence, were explored with linear mixed-effects (LME) models. Milk samples with SCC 400 × 103 (cells/mL) and ≥250/mL Colony Forming Units of one or two udder pathogens (in the microbiological examination) were defined as subclinical mastitis positive. Subclinical mastitis was found in 53 % (n = 1336) of microbiologically examined milk samples, with Staphylococcus spp. being the most prevalent amongst isolated pathogens. A positive correlation was found between SCC and TBC values (r = 0.687, p 0.05). MLS (p < 0.01), age class of animals (p < 0.05) and lactation month (p < 0.05) affected SCC of milk samples. The LME model, with SCC milk values ≥400 × 103 as dependent variables, revealed a significant effect of microclimate (β = 0.014, SE = 0.004, p < 0.001) and microorganism group [F(1,162) = 4.29, p < 0.001] on SCC. The MHC DQA2 allele B1 ("0602") was found at a lower frequency in ewes with subclinical mastitis (p < 0.05). In conclusion, microclimate and MLS (from the abiotic factors) and microorganism group, age class of ewes and lactation month (from the biotic factors) had a significant effect on milk SCC, while age class of ewes and lactation month (from the biotic factors) had a significant effect on subclinical mastitis occurrence. To our knowledge, this is the first report exploring the effect of microclimate (THI), PM milking and DQA2 gene on subclinical mastitis of sheep reared under low-input management systems