Impact of increasing levels of condensed tannins from sainfoin in the grower-finisher diets of entire male pigs on growth performance, carcass characteristics, and meat quality.

Sainfoin is a protein-rich legume with an ideal amino acid profile and therefore could partly replace soybeans in the diets of growing pigs. However, sainfoin also contains a non-negligible amount of condensed tannins (CTs), which can act as antinutritional factors. Bioactive plant compounds, like hydrolysable tannins, have been suggested to be suitable in entire male (EM) production, as they impair the development of accessory sex glands and, by that, reduce boar taint compound levels without negatively impacting growth. It is unknown whether, similar to hydrolysable tannins, CTs from sainfoin reduce the incidence of boar taint without impacting growth performance, carcass traits, and meat quality. For the experiment, 48 Swiss Large White EM were assigned within litter to one of four grower (25-60 kg BW) and finisher (60-105 kg BW) diets supplemented with 0 (T0), 5 (T5), 10 (T10), and 15% (T15) sainfoin meal, respectively. The four diets were designed to be isocaloric and isoproteic. Increasing the dietary sainfoin level had no negative effect on growth performance or the carcass characteristics. Despite leading to a similar feed intake between the treatment groups, increasing the dietary sainfoin levels tended (P ≤ 0.08) to reduce the number of feeder visits but increased the time spent at the feeder as well as the feed intake per visit during the finisher period. By increasing sainfoin intake, the levels of C18:3n-3 and long-chain homologs linearly increased (P < 0.01) in the backfat and intramuscular fat (IMF), whereas in the backfat, but not the IMF, the 18:2n-6 levels decreased (P < 0.01). The latter triggered a greater (P < 0.01) desaturation rate (C18:1n-9/C18:0) of the saturated fatty acids, resulting in a greater (P < 0.01) proportion of monounsaturated fatty acid. Apart from a linear decrease (P = 0.02) in the androstenone levels in the longissimus thoracis (LT), increasing the sainfoin intake had no effect on the level of boar taint in the LT and backfat. As determined by the elevated correlation coefficient, skatole and indole levels, but not androstenone levels, in the adipose tissue seem to be reliable proxies for their respective levels in LT and, therefore, in pork. In conclusion, sainfoin is a suitable homegrown protein source for grower finisher pigs and can be included at up to 15% in the diet to replace 7% of soybean in a diet without producing any noteworthy effects on growth, whereas the impact of CTs on boar taint was limited

Sodium hydroxide enhances extractability and analysis of proanthocyanidins in ensiled sainfoin (onobrychis viciifolia)

Little information exists on the effects of ensiling on condensed tannins or proanthocyanidins. The acetone–butanol–HCl assay is suitable for measuring proanthocyanidin contents in a wide range of samples, silages included, but provides limited information on proanthocyanidin composition, which is of interest for deciphering the relationships between tannins and their bioactivities in terms of animal nutrition or health. Degradation with benzyl mercaptan (thiolysis) provides information on proanthocyanidin composition, but proanthocyanidins in several sainfoin silages have proved resistant to thiolysis. We now report that a pretreatment step with sodium hydroxide prior to thiolysis was needed to enable their analysis. This alkaline treatment increased their extractability from ensiled sainfoin and facilitated especially the release of larger proanthocyanidins. Ensiling reduced assayable proanthocyanidins by 29%, but the composition of the remaining proanthocyanidins in silage resembled that of the fresh plants

Behavioural changes to moderate heat load in grazing dairy cows under on-farm conditions

Heat stress poses an increasing risk to welfare, health and productivity of dairy cows, especially for cows on pasture. To apply timely mitigation strategies for grazing cows, simple indicators are needed that signal heat stress. We conducted an exploratory study on the behaviour of grazing dairy cows in relation to the environmental heat load on four commercial dairy farms in Switzerland with herd sizes ranging from 20 to 57 cows. In a scan-sampling procedure standing/lying, feeding/ruminating, low inter-individual distances, proximity to drinker, use of natural shade and insect infestation were observed during 30 days (5–9 days/per farm). Additionally, 10 focal cows per farm were equipped with accelerometers to analyse lying duration and locomotor activity during on average 46 days per farm. On one farm all cows (N = 57) were equipped with GPS devices which were used to calculate inter-individual distances among cows continuously during 69 days. Air temperature and relative humidity were recorded to calculate the temperature-humidity index (THI). For behaviours recorded in direct observations, a principal component analysis was performed for variable reduction. The first three principal components (PC) as well as the variables from automatic measurements were used as outcome variables in mixed effects models with daily maximum THI (THImax), time of day (continuous, in 10 min intervals) and their interaction as explanatory variables. The three PCs could be described as: “feeding and standing”, “proximity to drinker” and “standing in close proximity and seeking shade”. The daily pattern of these PC's differed by THImax (interaction time of day * THImax; all p < 0.01). On days with high THImax compared to days with lower THImax cows were seen more often close to the drinker in the morning, but not in the afternoon when they were observed standing close to each other and in the shade. On days with high THImax, cows also were lying less and increased their locomotor activity towards noon (interaction time of day * THImax; p < 0.001). Data from GPS devices confirmed the findings: On days with high THImax, cows reduced their inter-individual distances over the course of the day, while this was not observed on days with lower THImax (interaction time of day * THImax; p < 0.001). Insect infestation increased with higher THImax. We conclude that a distinct change in daily behavioural patterns, especially a reduction of lying behaviour, an increase in locomotor activity and a decrease in inter-individual distances could be used to monitor heat stress of dairy cows on pasture

Benefits of condensed tannins in forage legumes fed to ruminants:Importance of structure, concentration, and diet composition

Condensed tannins (CTs) account for up to 20% of the dry matter in forage legumes used as ruminant feeds. Beneficial animal responses to CTs have included improved growth, milk and wool production, fertility, and reduced methane emissions and ammonia volatilization from dung or urine. Most important is the ability of such forages to combat the effects of gastrointestinal parasitic nematodes. Inconsistent animal responses to CTs were initially attributed to concentration in the diet, but recent research has highlighted the importance of their molecular structures, as well as concentration, and also the composition of the diet containing the CTs. The importance of CT structural traits cannot be underestimated. Interdisciplinary research is the key to unraveling the relationships between CT traits and bioactivities and will enable future on-farm exploitation of these natural plant compounds. Research is also needed to provide plant breeders with guidelines and screening tools to optimize CT traits, in both the forage and the whole diet. In addition, improvements are needed in the competitiveness and agronomic traits of CT-containing legumes and our understanding of options for their inclusion in ruminant diets. Farmers need varieties that are competitive in mixed swards and have predictable bioactivities. This review covers recent results from multidisciplinary research on sainfoin (Onobrychis Mill. spp.) and provides an overview of current developments with several other tanniniferous forages. Tannin chemistry is now being linked with agronomy, plant breeding, animal nutrition, and parasitology. The past decade has yielded considerable progress but also generated more questions — an enviable consequence of new knowledge

Benefits of Condensed Tannins in Forage Legumes Fed to Ruminants: Importance of Structure, Concentration, and Diet Composition

Condensed tannins (CTs) account for up to 20% of the dry matter in forage legumes used as ruminant feeds. Beneficial animal responses to CTs have included improved growth, milk and wool production, fertility, and reduced methane emissions and ammonia volatilization from dung or urine. Most important is the ability of such forages to combat the effects of gastrointestinal parasitic nematodes. Inconsistent animal responses to CTs were initially attributed to concentration in the diet, but recent research has highlighted the importance of their molecular structures, as well as concentration, and also the composition of the diet containing the CTs. The importance of CT structural traits cannot be underestimated. Interdisciplinary research is the key to unraveling the relationships between CT traits and bioactivities and will enable future on-farm exploitation of these natural plant compounds. Research is also needed to provide plant breeders with guidelines and screening tools to optimize CT traits, in both the forage and the whole diet. In addition, improvements are needed in the competitiveness and agronomic traits of CT-containing legumes and our understanding of options for their inclusion in ruminant diets. Farmers need varieties that are competitive in mixed swards and have predictable bioactivities. This review covers recent results from multidisciplinary research on sainfoin (Onobrychis Mill. spp.) and provides an overview of current developments with several other tanniniferous forages. Tannin chemistry is now being linked with agronomy, plant breeding, animal nutrition, and parasitology. The past decade has yielded considerable progress but also generated more questions-an enviable consequence of new knowledge

Effect of exchanging Onobrychis viciifolia and Lotus corniculatus for Medicago sativa on ruminal fermentation and nitrogen turnover in dairy cows

The objective of the study was to determine the effect of feeding sainfoin (SF; Onobrychis viciifolia) and birdsfoot trefoil (BT; Lotus corniculatus), 2 temperate climate forage legumes that contain condensed tannins (CT), on ruminal fermentation and N turnover in dairy cows. Six ruminally cannulated multiparous dairy cows (milk yield = 40 kg/d; 36 d in milk) were used in a replicated 3 × 3 Latin square design. All animals were fed basal diets containing 20% pelleted SF (223 g of CT/kg of dry matter), BT (30.3 g of CT/kg of dry matter), or alfalfa (AL) and concentrate to meet their predicted nutrient requirements. Each experimental period consisted of a 21-d adaptation period in a tiestall, followed by a 7-d collection period in metabolic crates, where feces and urine were collected quantitatively. During the 7-d period, milk yield was recorded daily and milk samples were taken at each milking. Blood, ruminal fluid, and papillae were sampled on d 2 and 5. The relative abundance of selected bacterial strains in ruminal fluid and the gene expression of transporter genes in the papillae were determined with quantitative PCR. Total volatile fatty acids and the abundance of the cellulolytic bacteria Prevotella spp. and Ruminococcus flavefaciens decreased with SF compared with AL. The relative gene expression of the monocarboxylate transporter 1 was increased with BT compared with AL and SF. Total yields of milk, milk fat, and milk protein were similar among treatments. The proportion of 18:3n-3 in milk fat was greater and those of 22:5n-3 and 22:6n-3 were lower with SF than with BT. The contents of urea N in blood (2.71, 3.45, and 3.90 mmol/L for SF, AL, and BT, respectively), milk (79.8, 100.1, and 110.9 mg/kg for SF, AL, and BT, respectively), and urine were lower with SF than with AL and BT, and a trend toward a lower ruminal ammonia content occurred with SF compared with BT. Intake and excretion of N with milk were similar among treatments, but urine N was lower with SF than with AL. The N excretion to N intake relation showed a shift in a part of urine N (17.5, 20.8, and 19.5% for SF, AL, and BT, respectively) to fecal N (45.2, 41.3, and 38.5% for SF, AL, and BT respectively) with SF compared with AL and BT. In conclusion, SF and BT differed in their effects on fermentation and milk fatty acid profile and SF also showed potential to decrease metabolic and environmental loads. The main reason for the different efficiency was likely a higher CT content of SF compared with BT.ISSN:0022-0302ISSN:1525-319

Ability of 3 tanniferous forage legumes to modify quality of milk and Gruyère-type cheese

Condensed tannins (CT) may affect ruminal biohydrogenation of dietary polyunsaturated fatty acids. A feeding experiment was conducted with 24 Holstein cows to evaluate whether diets containing CT from different forage legumes can increase polyunsaturated fatty acids, especially n-3 fatty acid content in milk and cheese, without affecting negatively their physicochemical and sensorial properties. Cows were assigned to 4 treatment groups (n = 6) for 52 d, divided into 2 periods: a control period (CoP) and an experimental period (ExP). During the CoP, cows received a basal diet composed of hay, corn silage, ExtruLin (Trinova Handel & Marketing AG, Wangen, Switzerland), concentrate, and alfalfa (AF) in a ratio of 45:25:5:7:18. In the ExP, in 3 of the 4 groups AF was replaced by either sainfoin (SF; 19% CT in dry matter) or 1 of 2 cultivars of birdsfoot trefoil [Polom (BP), 3% CT; Bull (BB), 5% CT]. At the end of each period, milk was collected on 3 consecutive days and analyzed for milk gross composition and fatty acid profile and was processed to Gruyère-type cheese. A trained panel assessed the sensory quality of raw milk and cheese using discriminative and descriptive tests. This experimental design consisting of AF in both the CoP and ExP allowed us to quantify effects due to lactation stage and experimental diets. In both the CoP and ExP, dry matter intake and milk yield did not differ among treatment groups. From the CoP to the ExP, milk urea content was reduced by 23% with SF, remained unchanged with BP, and tended to increase with AF and BB. The odor of the raw BB milk was judged to be different from AF milk. With SF, switching from the CoP to the ExP resulted in a 17% increase of the 18:3n-3 proportion in milk and cheese lipids. In BP cheese, the increase was 3%, whereas it tended to decrease in BB cheese. Additionally, the 20:5n-3 and 22:5n-3 proportions tended to increase in SF cheese from the CoP to the ExP. Compared with the AF cheeses, cheeses from cows fed CT-containing legumes were judged harder and tended to be less adhesive to the palate. In addition, SF and BP cheeses had less rind. In conclusion, feeding SF compared with BB and BP increased the content of 18:3n-3 in the milk and the cheese without a negative effect on flavor of the cheese. Despite a similar CT content, the 2 birdsfoot trefoil cultivars had opposite effects on milk urea and 18:3n-3 deposition, suggesting that, besides the content, the chemical structure may have had an important effect on the CT efficacy.ISSN:0022-0302ISSN:1525-319