Artenreiches Rauhfutter als Alleinfutter und Fettsäurenmuster der Milch

In two experiments it was investigated which factors to what extent determine the fatty acid composition milk when cows are grazing high alpine pastures. The influences of altitude per se, of alpine forage quality, of concentrate-free diet type and of the overall grazing effect were separated by the experimental design. The most important factor which significantly elevated the concentrations of CLA, α-linolenic acid (ALA) and n-3 PUFA in milk fat was found to be the alpine diet type, i.e. the feeding of roughage-only (as well hay as pasture of as well lowland as alpine origin) with omission of concentrates and maize. Additionally a clear positive effect of the forage quality of alpine pastures on ALA concentration in milk fat was found. The latter effect is assumed to be linked to specific plant ingredients (eg. tannins) and to the low energy density of the alpine flora, which may influence the ruminal biohydrogenation of native ALA. An effect of altitude per se (hypoxia) was not found

Effect of PUFA at sn-2 position in dietary triacylglycerols on fatty acid composition of adipose tissue in growing-finishing pigs

A potential effect of the specific composition of plant oil triacylglycerols, with PUFAs predominantly esterified at the sn-2 position, on the fatty acid composition of adipose tissues of pigs was investigated. Two blends with a ratio of 1/3 and 3/1 of soybean oil and beef tallow were randomised or left unmodified and fed at 4% of a conventional diet to 4 * 12 pigs. The randomisation of fatty acids at sn-1, 2 and 3 positions did not affect the fatty acid composition of pig adipose tissues. It is concluded that the position of PUFA in dietary triacylglycerols is of minor relevance for the composition of depot fat in growing-finishing pig

Effect of PUFA at sn-2 position in dietary triacylglycerols on fatty acid composition of adipose tissue in growing-finishing pigs

A potential effect of the specific composition of plant oil triacylglycerols, with PUFAs predominantly esterified at the sn-2 position, on the fatty acid composition of adipose tissues of pigs was investigated. Two blends with a ratio of 1/3 and 3/1 of soybean oil and beef tallow were randomised or left unmodified and fed at 4% of a conventional diet to 4 * 12 pigs. The randomisation of fatty acids at sn-1, 2 and 3 positions did not affect the fatty acid composition of pig adipose tissues. It is concluded that the position of PUFA in dietary triacylglycerols is of minor relevance for the composition of depot fat in growing-finishing pig

Sire-feed interactions for fattening performance and meat quality traits in growing-finishing pigs under a conventional and an organic feeding regimen

In a two-factorial feeding trial 120 growing-finishing pigs from eleven sires were fed on an organic (ORG) or a conventional (CON) diet. Diet ORG contained mainly oil press cakes and legume grains as protein source containing higher protein and crude fiber content along with slight deficiencies of limiting amino acids. Pigs were allocated to treatments balanced according to litter, sex and initial weight. Feed was offered ad libitum. Feed consumption, weight gain as well as carcass, meat and fat quality traits were recorded. ORG fed animals had lower weight gain, poorer feed conversion, lower loin muscle area, higher intramuscular fat content, higher ultimate pH (loin, ham), and a higher PUFA content in backfat. Despite for cook loss and dressing percentage, no sire-feed interactions were found. This indicates no need for a performance test, specifically designed for organic production. However, weight of the breeding values for the various traits and selection criteria should be adapted to the needs of organic production

The accuracy of intake estimation based on the use of alkane controlled-release capsules and faeces grab sampling in cows

Alkanes are digesta markers for use as a research tool giving the opportunity to estimate feed intake and digestibility in vivo. The development of intra-ruminal controlled-release capsules (CRC) offers a practical method of dosing even-chain alkanes and may give less diurnal variability of marker excretion improving the validity of grab-faecal sampling. This was tested in the present study by total faeces collection in four cows for 7 days. Dry matter intake was 10.4 kg forages and 10.4 kg concentrate (diet 1) and 15.1 kg forage (diet 2). The recovery (proportion of dosed or dietary alkane intake found in faeces) of C$_{31}$ was lower than that of C$_{32}$ and consequently underestimated intake. C$_{33}$ and C$_{32}$ had similar recoveries giving accurate intake estimates from pooled samples from total daily faecal collections and also from grab samples taken at 6.30 a.m. The study confirms that a single injection for gas chromatography is sufficient. Alkane CRC are concluded to be an accurate method for estimating forage intake of cows consuming diets with or without concentrate when spot sampling of faeces is conducted over 7 days and only moderately less precise when sampling over 5 days.Précision de l'ingestion estimée par des capsules à libération contrôlée d'alcanes chez les vaches à partir d'échantillons de fèces. Les alcanes sont en passe de devenir des marqueurs prometteurs, en tant qu'outil pour estimer l'ingestion in vivo. Des alcanes à chaînes paires administrés dans le rumen sont comparés à des alcanes à chaînes impaires naturellement présents dans la cire cuticulaire des végétaux ingérés par le ruminant. Le développement de capsules intra-ruminales à libération contrôlée (CRC) facilite la distribution à l'animal d'alcanes à chaînes paires et pourrait ainsi diminuer la variation journalière de l'excrétion du marqueur en augmentant la validité des échantillons de fèces. C'est ce qui a été testé ici, en récoltant en totalité les excrétions fécales de 4 vaches pendant une semaine. Les quantités ingérées étaient de 10,4 kg de MS pour le fourrage et de 10,4 kg de MS pour le concentré (ration 1) et 15,1 kg de MS pour le fourrage (ration 2). Le taux de récupération du C$_{31}$ était inférieur à celui du C$_{32}$, conduisant donc à une sous-estimation de l'ingestion. Par contre, les taux de récupération du C$_{33}$ et C$_{32}$ étaient presque égaux, et donnaient des estimations précises avec les échantillons de la collecte quotidienne totale des fèces, mais aussi avec les prélèvements rectaux à 06:30 h. La prise d'échantillons de fèces devrait se faire pendant chacun des 7 jours de la durée de collecte recommandée, les estimations étant un peu moins précises lorsque la collecte est sur 5 jours. La libération de marqueur à partir de la capsule avait cessé au bout de 5 semaines. En conclusion, les alcanes administrés par CRC sont considérés comme une méthode précise pour estimer l'ingestion chez des vaches recevant des rations avec ou sans concentré