BackgroundAccording to the Norwegian animal welfare regulations, it has been forbidden to build new tie-stall barns since the end of 2004. Previous studies have shown that cow performance and health differ between housing systems. The interaction between housing system and herd size with respect to performance and disease incidence has not been evaluated.MethodsCow performance and health in 620 herds housed in free-stall barns were compared with in 192 herds housed in tie-stall barns based on a mail survey and data from the Norwegian Dairy Herd Recording and Cattle Health Systems. The housing systems herds were comparable with respect to herd size (15-55 cows). Associations between performance/disease incidence and housing system, herd size and year of building the cow barn were tested in general linear models, and values for fixed herd size of 20 and 50 cows were calculated. On the individual cow level mixed models were run to test the effect of among others housing system and herd size on test-day milk yield, and to evaluate lactation curves in different parities. All cows were of the Norwegian Red Breed.ResultsAverage milk production per cow-year was 134 kg lower in free-stall herd than in tie-stall herds, but in the range 27-45 cows there was no significant difference in yields between the herd categories. In herds with less than 27 cows there were increasingly lower yields in free-stalls, particularly in first parity, whereas the yields were increasingly higher in free-stalls with more than 45 cows.In free-stalls fertility was better, calving interval shorter, and the incidence rate of teat injuries, ketosis, indigestions, anoestrus and cystic ovaries was lower than in tie-stalls. All of these factors were more favourable in estimated 50-cow herds as compared to 20-cow herds. In the larger herd category, bulk milk somatic cell counts were higher, and the incidence rate of mastitis (all cases) and all diseases was lower.ConclusionThis study has shown that there is an interaction between housing system and herd size, and that performance and health is not universally better in small free-stalls than in tie-stalls.

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Piglet mortality is still a significant welfare and ethical matter in pig production, as well as an economical challenge for the farmer. Most of the mortality occurs early after farrowing, and previous studies have shown that the farm`s management routines, especially around farrowing, are important factors to reduce it. When sows are loose-housed at farrowing and in the following lactation period, it puts higher demands on management input from the farmer to keep piglet mortality low. The objective of this study was to assess the importance of different management routines around the time of farrowing, and other farm qualities for piglet survival in loose-housed herds. To study risk factors for herd piglet mortality, a cross-sectional field survey was carried out in Norway in the year 2013, and included 52 commercial herds with hybrid LY sows (Norwegian Landrace x Swedish Yorkshire). The farms were visited once, and the farmers answered a questionnaire about their management practices. The outcome was the average herd pre-weaning mortality in the years of 2012-2013. To include as many management factors as possible into the multivariable linear regression model, we generated a new variable based on 4 management routines: 3 routines at farrowing (presence at 80-100% of the farrowings, drying newborn piglets, and practice split suckling), and one concerning farmer´s contact with the sows. This variable was called "Management type" (M), and were divided into 4 categories with increasing effort; M1 herds without any of the 4 mentioned routines, M2 had contact with sows >2 times per day, M3 performed the 3 routines at farrowing, and M4 combined the high sow contact and the 3 routines. The predicted values of mean herd piglet mortality for M1, M2, M3 and M4 were 20.1%, 17.0%, 16.2% and 13.3% respectively. The farmer`s increased management effort was associated with lower piglet mortality (P<0.05). The farmer`s effort at critical times together with systematic and important routines, and having frequent contact with the sows, makes a huge difference for piglet survival. The farmers are credited for this work by having lower piglet mortality as a result.

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The livestock production sector is facing challenges to find alternative feed resources and nutritional strategies to mitigate enteric methane (CH4) emissions from ruminants. Recently, marine macroalgae have emerged as potential anti-methanogenic feed ingredients due to their ability to suppress enteric CH4 production in ruminants. The anti-methanogenic properties of macroalgae have been ascribed to the contents of secondary metabolites, such as halogenated compounds e.g., bromoform in red species, and polyphenols or isoprenoids in brown species. These compounds may suppress methanogenesis by inhibiting the growth and activity of methanogens or by altering rumen fermentation pathways and the patterns of volatile fatty acids production. On the other hand, the anti-methanogenic macroalgae, particularly when added to diets in large amounts, are known to reduce animal performance, due to the presence of special and poorly degradable carbohydrates. Thus, finding a proper balance between the abilities to reduce CH4 emissions and sustain animal performance is important.