Meta-analysis of the influence of Saccharomyces cerevisiae supplementation on ruminal parameters and milk production of ruminants

Beef and dairy products suffer from a negative health image, related to the nature of their lipid fraction. Rumen lipid metabolism involves the presence of saturated lipids in ruminant tissues. Lipolysis, fatty acid biohydrogenation and formation of microbial fatty acids in the rumen and their effects on rumen outflow of fatty acids are discussed. Special emphasis is given to the formation of trans-fatty acids and the possibilities of decreasing biohydrogenation. Small differences in intestinal digestibilities of fatty acids are mentioned, followed by a discussion on transfer of absorbed fatty acids into milk and adipose tissue lipids. The preferential retention of polyunsaturated fatty acids as well as the balance between synthesis and incorporation of fatty acids in tissues is described. Dietary means for the modification of milk fat are listed, with special emphasis on the possibilities for enrichment in polyunsaturated fatty acids and the presence of conjugated linoleic acids. A description of the nature and development of fat depots in beef cattle is followed by a discussion of breed, conformation and feed effects on adipose tissue distribution and fatty acid composition. Special emphasis is given to the very lean Belgian Blue double-muscled breed. The review ends with a consideration of the limits to the modification of ruminant fats, involving considerations of consumer acceptance as well as animal welfare and environmental effects.

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Targets and procedures for altering ruminant meat and milk lipids

Relationships between muscle characteristics and meat quality traits of young Charolais bulls.

Element balances as a tool for sustainable nutrient management: a critical appraisal of their merits and limitations within an agronomic and environmental context

Eight horses were allotted into pairs consisting of one cecum- and right ventral colon-fistu- lated animal and one cecum-fistulated animal They were fed daily at the same level of intake either a high- fiber (HF) or a high-starch (HS) diet without or with 10 go f aSaccharomyces cerevisiae preparation, in a 4 × 4 Latin square design The HS diet provided a starch overload (ie, 34 g starchkg −1 BWmeal −1 ) while main- taining a high amount of fiber intake (ie, dietary NDF/ starch ratio was 10) A 21-d period of adaptation to the treatments occurred before cecal and colonic contents were withdrawn 4 h after the morning meal to count total anaerobic, cellulolytic, and lactic acid-utilizing bacteria, lactobacilli, and streptococci Lactic acid, vola- tile fatty acids, ammonia concentrations, and pH were measured on cecal and colonic fluid samples collected hourly during the first 12-h postfeeding When the HS diet was fed, the concentration of total anaerobic and lactic acid-utilizing bacteria increased (P < 0001), whereas that of cellulolytic bacteria decreased (P < 005) in the cecum The concentration of lactobacilli and streptococci increased (P < 0001) in the cecal and co- lonic contents These alterations of the microbial pro- files were associated with decreases (P < 0001) of pH, (acetate + butyrate)/propionate ratio and with an in- crease (P < 0001) of lactic acid concentration Supple- menting the S cerevisiae preparation increased (P < 001) the concentration of viable yeast cells, averaging 43 × 10 6 and 45 × 10 4 cfu/mL in the cecal and colonic contents, respectively Yeast supplementation had al- most no effect on microbial counts in the cecum and colon The supplementation of S cerevisiae appeared to modify (P < 005) pH, concentrations of lactic acid and ammonia, molar percentages of acetate and buty- rate with the HS diet and ((acetate + butyrate)/propio- nate) ratio when the HF diet was fed The effects of the S cerevisiae preparation were greater in the cecum than in the colon, which coincided with the abundance of yeast cells When the digestion of starch in the small intestine was saturated, the effect of the addition of a S cerevisiae preparation appeared to limit the extent of undesirable changes in the intestinal ecosystem of the horse

Effect of a preparation of Saccharomyces cerevisiae on microbial profiles and fermentation patterns in the large intestine of horses fed a high fiber or a high starch diet.

Introduction Even at a similar energy concentration of the diet, energy source may affect animal performance. O wens et al. (1997) reported that daily dry matter (DM) intake tended to be lowest for wheat-based diets and highest for milo and oat-based diets. O’M ara et al. (1997) found a lower pH and less ammonia in the rumen of lactating cows, when unmolassed beet pulp was replaced with ground wheat. Contrary to the results of O’M ara et al. (1997), M alestein et al. (1984) found a greater risk for lactic acidosis for citrus and beet pulp than for maize meal and tapioca. For years it has been known that rapidly degradable carbohydrates may provoke acidosis (H untington and B ritton 1979; F iems et al. 1993). Furthermore, low ruminal pH may inhibit cellulose digestion (M ould et al. 1983) and decrease efficiency of microbial protein synthesis (R ussell et al. 1979).



As energy concentration of the diet is important for finishing cattle (B oucqu& eacute; et al. 1980), the amount of roughage is rather limited. This may result in sub-clinical acidosis with a negative impact on animal performance (O wens et al. 1998), especially when the diet is rich in rapidly fermentable carbohydrates. Therefore an experiment was conducted to investigate the impact of energy source in the finishing diet on voluntary daily feed intake, daily liveweight gain, feed efficiency, blood metabolites and carcass quality.



Energy source may also affect meat quality. C asteels et al. (1969) found differences in meat colour when concentrates were based on cereals or sugarbeet pulp. W ood (1984) reported that the concentrate : forage ratio in the diet affects the fatty acid composition of body fat through an increase in propionate production in the rumen. Therefore the effect on meat quality was also studied.

Effect of amount and degradability of dietary starch on animal performance and meat quality in beef bulls

Information concerning 493 single calvings of the double-muscled beef cow herd of the institute was collected to investigate the relationship between the characteristics of dams and calves with regard to dystocia. Factors affecting dystocia are similar in double-muscled cattle to those in non-double-muscled cattle but the occurrence of dystocia is greatly increased in double-muscled cows. Incidence of caesarean section was significantly correlated with parity (–0·243), age of dam (–0·232), post-partum dam weight (–0·185), and calf birth weight (0·164). Caesarean deliveries were required for 89·5% of the parturitions. Calvings without caesarean section were characterized by higher means for post-partum dam live weight (634·7 kg), age (1675·5 days), parity (3·1) and the ratio of post-partum dam weight to calf birth weight (14·4), compared with 580·2 kg, 1251·1 days, 2·1, and 11·8, respectively for births with caesarean setion, while calf birth weight was lower in non-caesarean calvings (45·8 v. 49·9 kg). Caesarean births involved more male calves than females (55 v. 45%). Even when calf birth weight was 30 kg or lower, and also in multiparous cows, 40 and 86% of the deliveries, respectively, still occurred with a caesarean section. Incidence of caesarean section could not be accurately predicted from pre-partum characteristics such as pre-partum dam weight, age and parity.

Relationship between dam and calf characteristics with regard to dystocia in Belgian Blue double-muscled cows

Energy and protein requirements of Belgian Blue double-muscled bulls

Performance of double-muscled bulls affected by grazing or restricted indoor feed intake during the growing period followed by finishing up to two different slaughter weights

Chemical composition, digestibility, nutritive value and intake of hay from an agri-environmental management (EH) were compared with those from hay (Lolium perenne) from an intensive management (IH). IH was of low to moderate quality because of unfavourable weather conditions. EH was harvested mid-June of 2000 (EH1) and 2001 (EH2) on the same sward that had not received mineral fertilizer for 10 years. The EH was characterized by a species-rich botanical composition. On average, it had lower contents of protein (32%), NDF (9%) and ash (35%), and a higher concentration of water-soluble carbohydrates (117%) than IH. Digestibility of dry and organic matter, determined with sheep, was not different between IH and EH and averaged 59 and 63%, respectively. Crude fibre and NDF digestibility were lower in EH (58 and 57%, respectively) than in IH (70 and 69%, respectively). Net energy value for lactation did not differ between IH and EH and amounted to 4.78 MJ per kg DM. True protein digested in the small intestine and rumen degraded protein balance were lower in EH (63 and -60 g per kg DM) than in IH (71 and -33 g per kg DM). Intake of hay was investigated in Holstein-Friesian heifers and Belgian Blue double-muscled heifers (mean BW 280 +/- 22 kg and 269 +/- 21 kg, respectively), and in Belgian Blue non-lactating and non-pregnant double-muscled cows (initial BW 642 +/- 82 kg), using a cross-over design. Hay was freely available. It was supplemented with 1 kg concentrate daily. Dry matter intake from hay was higher for EH than for IH in heifers (4% and 13%, respectively in Holstein-Friesian and Belgian Blue heifers) and in cows (22%). Hay from an agri-environmental management may be used for low-performing animals, as energy intake only exceeded maintenance requirements by 20 to 35%. Several characteristics of EH were different between years, such as dry matter digestibility, net energy value for lactation and fermentable organic matter content.

L. O. Fiems

Papers

Effect of amount and degradability of dietary starch on animal performance and meat quality in beef bulls

Relationship between dam and calf characteristics with regard to dystocia in Belgian Blue double-muscled cows

Energy and protein requirements of Belgian Blue double-muscled bulls

Performance of double-muscled bulls affected by grazing or restricted indoor feed intake during the growing period followed by finishing up to two different slaughter weights

Agri-environmental grass hay: nutritive value and intake in comparison with hay from intensively managed grassland.