Impact of US Brown Swiss genetics on milk quality from low-input herds in Switzerland: interactions with grazing intake and pasture type

This study investigated the effect of, and interactions between, contrasting crossbreed genetics (US Brown Swiss [BS] × Improved Braunvieh [BV] × Original Braunvieh [OB]) and feeding regimes (especially grazing intake and pasture type) on milk fatty acid (FA) profiles. Concentrations of total polyunsaturated FAs, total omega-3 FAs and trans palmitoleic, vaccenic, α-linolenic, eicosapentaenoic and docosapentaenoic acids were higher in cows with a low proportion of BS genetics. Highest concentrations of the nutritionally desirable FAs, trans palmitoleic, vaccenic and eicosapentaenoic acids were found for cows with a low proportion of BS genetics (0-24% and/or 25-49%) on high grazing intake (75-100% of dry matter intake) diets. Multivariate analysis indicated that the proportion of OB genetics is a positive driver for nutritionally desirable monounsaturated and polyunsaturated FAs while BS genetics proportion was positive driver for total and undesirable individual saturated FAs. Significant genetics × feeding regime interactions were also detected for a range of FAs.

Integrated control of gastrointestinal nematodes in lambs using a bioactive feed × breed approach

Forages rich in condensed tannins have repeatedly shown potential to reduce gastrointestinal nematode infection in sheep. Similarly, several breeds of sheep have shown a relative resistance to gastrointestinal nematodes (GIN). We hypothesised that additive or even synergic effects may arise from the combination of a relatively resistant breed and a diet rich in condensed tannins. In study I, 160 lambs of the native Red Engadine Sheep (RES) and 113 lambs of the Swiss White Alpine sheep (SWA) were artificially infected with GIN and subsequently grazed for 52 days. The lambs were then distributed to 2 groups for a 14-day experimental feeding period. One group received a diet with a proportion of 55% sainfoin and was compared to a control group on the basis of faecal egg counts (FEC). In study II, 25 RES and 27 SWA lambs grazed infectious pastures for 37 days and were subsequently fed for 13 consecutive days with approximately 100% sainfoin or control forage. In addition to the FEC determination at the start and the end of the experimental feeding, the 52 lambs in study II were slaughtered and necropsied to determine their worm burden. FEC at the end of the feeding period were significantly lower in sainfoin fed lambs compared to controls in study I (p<0.001) as well as in study II (p=0.012). Breed, animal age, live weight, sex and the interaction of breed and treatment did not affect FEC in either study. The main nematode genera found in the sacrificed lambs of study II were Haemonchus spp., Teladorsagia spp., Nematodirus spp. and Trichostrongylus spp. Overall, RES had a significantly lower Haemonchus spp. (p=0.035) and Trichostrongylus spp. (p=0.003) worm burden compared to SWA. Regardless of breed, sainfoin feeding significantly reduced Teladorsagia spp. (p=0.049) and Nematodirus spp. (p<0.001) worm burden. Although, we could not demonstrate additive or synergic effects when using an integrated breed × sainfoin approach, the finding that a proportion of only 55% sainfoin in the diet led to a lower FEC compared to controls is important with respect to the implementation on producing farms.