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PubMed2006

Effects of fatty acid supplements on ruminal and total tract nutrient digestion in lactating dairy cows.

Saturated and unsaturated fatty acid supplements (FS) were evaluated for effects on ruminal digestion kinetics, and ruminal and postruminal nutrient digestion. Eight early lactation ruminally and duodenally cannulated cows (77 +/- 12 days in milk, mean +/- SD) were used in a replicated 4 x 4 Latin square design experiment with 21-d periods. Treatments were control and a linear substitution of 2.5% fatty acids from supplemented saturated FS (SAT; prilled, hydrogenated free fatty acids) for partially unsaturated FS (UNS; calcium soaps of long-chain fatty acids). All rations contained identical forage and concentrate components including 37.2% forage and 13.5% cottonseed. Saturated FS linearly decreased ruminal digestibility of dry matter and organic matter and linearly decreased ruminal neutral detergent fiber (NDF) digestibility. The reduction in ruminal NDF digestibility was because of a linear decrease in digestion rate and a linear increase in passage rate of potentially digestible NDF with increasing saturated FS. Total tract digestibility of NDF was not different between treatments because of compensatory postruminal digestion. Ruminal fatty acid and C18 fatty acid digestibility tended to increase linearly with increasing unsaturated FS, and postruminal C18 fatty acid digestibility decreased with increasing saturated FS. Saturated FS linearly decreased ruminal organic matter digestibility and decreased intestinal long-chain fatty acid digestibility, although differences in fatty acid digestibility may be partially explained by fatty acid intake.

Animals↗
PubMed1991

Effect of source and level of supplemental fat on total and ruminal organic matter and nitrogen digestion in dairy cows.

Effects of fat supplementation for dairy rations on digestibility and ruminal digestion were studied in four cows receiving a control diet (hay-concentrate) or this diet supplemented with 5 or 10% rapeseed oil or 10% tallow, according to a Latin square design. Neither total digestibility of DM, OM, and crude fiber nor ruminal OM digestibility was modified by lipid supply. Microbial N flow to the duodenum was calculated for solid-adherent bacteria and liquid-associated bacteria, using the turnover rate of liquid phase, the ruminal pools of bacteria and their concentrations in RNA, and diaminopimelic acid. Flows of total and bacterial duodenal OM and N did not depend on the fat content of the diet. In sacco ruminal degradation of DM was lower for a diet supplemented with 10% rapessed oil than for the control diet. The addition of rapeseed oil resulted in decreased acetate and increased propionate proportions in ruminal VFA and decreased ruminal ammonia after feeding. This trial showed that modifications in ruminal digestion did not have any negative consequence on OM degradation and did not modify ruminal N digestion.

Animal Feed↗
PubMed1992

Effects of lasalocid on selected ruminal and blood metabolites in young calves.

Twelve Holstein bull calves were ruminally cannulated at 5 d of age and assigned to 0 or 1 mg of lasalocid/kg of BW daily, administered postruminally via milk replacer or into the ruminal cannula. Calves were fed milk replacer for 8 wk and calf starter for 12 wk. Lasalocid administration was terminated at weaning in calves fed lasalocid in milk replacer. Ruminal pH tended to be higher in calves fed lasalocid ruminally than in calves on control treatment and averaged 5.9 and 5.6 and 5.4 and 5.1 during wk 1 to 8 and 9 to 12, respectively. Molar proportion of ruminal butyrate tended to be lower when lasalocid was added to the rumen, particularly after weaning. Blood beta-hydroxybutyrate and acetoacetate were lower when lasalocid was administered into the rumen after weaning and averaged .897 and .646 and .026 and .015 mM in calves on control and ruminal treatments, respectively. No effects of lasalocid administered via the milk replacer were observed, except for plasma NEFA, which were reduced postweaning. These data suggest that lasalocid reduces blood beta-hydroxybutyrate by changes in ruminal fermentation and subsequent metabolism of butyrate by ruminal epithelium.

3-Hydroxybutyric Acid↗
PubMed1993

Another theory for the action of ruminal buffer salts: decreased starch fermentation and propionate production.

Sodium carbonates have been fed to ruminants for more than 20 yr and, in many cases, have alleviated milk fat depression. These effects usually have been ascribed to increased ruminal buffering capacity, but this mode of action has several problems. For the buffering capacity to increase, the concentrations of ruminal bicarbonate, dissolved CO2, and Na have to increase. Ruminal fluid already is saturated with CO2, and the cation concentration of ruminal fluid is regulated closely to prevent hemoconcentration or hemodilution. Based on these latter observations, a significant increase in ruminal buffering capacity is unlikely. The action of bicarbonates is explained more easily by increased water intake, increased ruminal fluid dilution rate, increased flow of undegraded starch from the rumen, and decreased ruminal propionate production.

Animals↗
PubMed1996

Lasalocid and particle size of corn grain for dairy cows in early lactation. 2. Effect on ruminal measurements and feeding behavior.

The effects particle size of corn grain and the ionophore lasalocid on ruminal fermentation and feeding behavior of early lactation cows were examined. Eight multiparous and 4 primiparous cows in early lactation were fed diets (44% forage) with cracked or ground dried shelled corn grain and with or without lasalocid (360 mg/d per cow). The experiment was a replicated (n = 3) 4 x 4 Latin square design with 21-d periods and a 2 x 2 factorial arrangement of treatments. Ground corn decreased ruminal turnover time of starch, did not affect ruminal lactate concentrations, increased propionate, decreased the ratio of acetate to propionate, and decreased branched-chain fatty acids. The range of ruminal pH within a day increased with ground corn, but mean pH was unaffected by treatment. Lasalocid increased lactate concentrations and did not affect the ratio of acetate to propionate. Lasalocid increased total time spent ruminating, and ground corn decreased ruminal contractions. Lasalocid tended to increase water intake, and ground corn increased water intake. Interactions of lasalocid and particle size of the corn grain were observed for ruminal turnover time of starch and NDF, and ruminal pool size of acetate and total VFA.

Acetates↗
PubMed1996

Lasalocid effects on ruminal degradation of protein and postruminal supply of amino acids in Holstein steers.

Five ruminally and duodenally cannulated Holstein steers (305 kg) were used in a switchback experiment with three periods to evaluate two experimental treatments: a basal diet with or without 45 ppm of lasalocid. The basal diet contained approximately 43% rolled corn, 45% alfalfa hay, and 10% soybean meal (DM basis). Lasalocid did not affect feed intake or ruminal digestion of OM and NDF. Ruminal digestion of ADF tended to increase with supplemental lasalocid. Total tract digestion of OM, NDF, ADF, and N and intestinal flow of amino acids were not affected by lasalocid. Also, the ratio of microbial to nonmicrobial N fractions at the duodenum remained unchanged. Ruminal pH and concentrations of NH3, VFA, peptides, and amino acids were not affected by lasalocid. Ruminal protease activity decreased with supplemental lasalocid, but this decrease was not reflected in other variables, such as ruminal concentrations of peptides and amino acids. Ruminal deaminase activity remained unchanged. Thus, we concluded that dietary lasalocid did not alter ruminal protein degradation or postruminal flow of amino acids.

Amino Acids↗
PubMed1999

Predicting the effect of proteolysis on ruminal crude protein degradation of legume and grass silages using near-infrared reflectance spectroscopy.

Two studies were conducted to assess whether routine applications of near infrared reflectance spectroscopy could predict the effects of silage proteolysis on ruminal crude protein (CP) degradation of legume and grass silages. A preliminary study was conducted to assess the effect of laboratory drying method on ruminal CP degradation of silages. Thirty legume and grass silages were freeze-, oven-, or microwave-dried and incubated in situ in the ventral rumen of three ruminally cannulated cows for 24 h. Freeze-drying was considered least likely to alter ruminal CP degradation of the silages; therefore, oven- and microwave-drying were compared using first-order regression with freeze-drying. Oven-drying for 48 h at 55 degrees C compared favorably (R2 = 0.84) with freeze-drying. Microwave-drying resulted in a large bias (2.84 g/10(-1) kg of CP) and was poorly related (R2 = 0.48) to freeze-drying. In a second study, alfalfa and timothy were cut at three maturities and allowed to wilt for 0, 10, 24, 32, 48, and 54 h. Forages were ensiled in triplicate cylindrical mini silos and allowed to ferment for 120 d. After fermentation, silages were oven-dried, ground, and scanned on a near-infrared reflectance spectrophotometer. Duplicate, dried, 2-mm ground silage samples were incubated in the ventral rumen of three ruminally cannulated cows for 24 h. Forage species, maturity, and wilting time significantly affected 24-h ruminal CP degradation of the silages. Near-infrared reflectance spectroscopy accurately predicted (R2 = 0.91) 24-h ruminal CP degradation of silages. Data suggest near-infrared reflectance spectroscopy can accurately assess the effects of forage species, maturity, and wilting time (proteolysis) on 24-h ruminal CP degradation of legume and grass silages.

Animals↗
PubMed1995

[An oral-ruminal probe for rumen sampling in the adult sheep].

Ten adult (height: 63-85 cm) rumen-fistulated sheep were used to test the usefulness of an ororuminal probe and a suction pump for the acquisition of ruminal fluid. The use of these instruments in 50 samplings rendered 200 ml of ruminal fluid each time. The introduction of the probe took 18 +/- 6.5 s, whereby the probe was inserted to a length of 91.3 +/- 3.5 cm. The collection of 200 ml of ruminal fluid took 7.4 +/- 2.2 s. The sampling location was the ventral ruminal sack. By comparing the fluid taken by the ororuminal probe with samples taken via ruminal fistula by a tube-like probe no significant differences in regard to pH, total acidity, reduction potential, ammonia, acetate, L-lactate, sodium and chloride concentrations were found. However, significant differences between ororuminal probe samples and fistula samples were observed in regards to the concentrations of total volatile fatty acids, propionate, n-butyrate, i-butyrate, n-valeriate, i-valeriate, calcium, phosphate, magnesium and potassium. The differences were independent of the sampling order (ororuminal probe prior to fistula and vice versa). These results indicate that samples taken by the ororuminal probe do not contain sampling-dependent saliva residues. Those samples collected via fistula had consistently higher concentrations of total volatile fatty acids, propionate, n-butyrate, i-butyrate, n-valeriate, and i-valeriate, as well as higher concentrations of calcium, phosphate, magnesium and potassium than samples taken with the ororuminal probe. These results indicate that samples taken via fistula originated from more dorsal regions than the samples taken by ororuminal probe from the ventral ruminal sack. The ororuminal probe and the suction pump used proved to be useful for the collection of ruminal fluid from the ventral ruminal sack in adult sheep (height: 63-85 cm).

Animals↗
PubMed1996

Ammonia in ruminal and abomasal contents of cows with abomasal displacement.

Ruminal and abomasal ammonia concentrations were determined in cows with left displaced abomasum (LDA), right displaced abomasum (RDA), or abomasal volvulus (AV) before the abomasum was corrected, as well as one and three days later, and compared with those from healthy control cows fed hay or hay and concentrates. In LDA, RDA, and AV, ruminal and abomasal ammonia concentrations before correction of the position of the abomasum significantly exceeded ammonia concentrations in control cows during hay diet. In LDA, ruminal and abomasal ammonia concentration before correction did not differ from control cows during hay/concentrate diet, whereas in RDA and AV, ruminal and abomasal ammonia significantly exceeded control cows during hay/concentrate diet. Ammonia concentrations significantly differed between forms of displacement before correction and one day after correction, with LDA showing lowest, RDA intermediate and AV highest ruminal ammonia values, and LDA and RDA showing lower abomasal ammonia values than AV. However, three days after correction, ruminal and abomasal ammonia concentrations did not differ between LDA, RDA and AV. Up to the third day after correction, ruminal and abomasal ammonia concentrations significantly decreased in LDA, RDA and AV. On the third day after correction, ruminal and abomasal ammonia concentrations in LDA, RDA and AV did not differ from control cows during hay diet, and were significantly lower than in control cows during hay/concentrate diet. These findings suggest disturbances in the protein metabolism of cows with abomasal displacement.

Abomasum↗
PubMed1986

Tissue specific deficiency of lysozyme in ruminants.

The distribution of lysozyme in tissues and fluids of ruminants was examined and it was determined that, except for a few tissues, ruminants were deficient in lysozyme activity compared with other species. The prominent exception was the abomasum of cattle, which had high levels of lysozyme activity. Mixing and extraction studies indicated that the lysozyme deficiency of ruminants was due neither to the presence of inhibitors of lysozyme in ruminant tissue nor to the binding of lysozyme in a manner that interfered with its enzymatic activity or assay. Other investigations have indicated that isozymes of lysozyme are present in ruminants and this study suggests that ruminants have only low levels of the isozyme that is the major isozyme of lysozyme in non-ruminants.

Abomasum↗
PubMed2000

Epidemiology of paratuberculosis in wild ruminants studied by restriction fragment length polymorphism in the Czech Republic during the period 1995-1998.

In two studies carried out during the period 1995-1998, paratuberculosis was diagnosed in domestic and wild ruminants in the Czech Republic. The isolated Mycobacterium avium subspecies paratuberculosis strains were analysed by standardised restriction fragment length polymorphism (RFLP) [Pavlik, I., Horvathova, A., Dvorska, L., Bartl, J., Svastova, P., du Maine, R., Rychlik, I., 1999. J. Microbiol. Methods 38, 155-167]. In December 1992, 19 late pregnant Charolais heifers were imported to the Czech Republic from Hungary (original import from France to Hungary). One 11-month-old heifer roamed in the wild in a range of approximately 15-20km for 7 months from November 1993 to May 1994. Upon capture, the animal showed clinical signs of paratuberculosis (emaciation and diarrhoea). Seven other animals from the same herd were infected with the identical RFLP type B-C1 of M. paratuberculosis. During the period 1995-1996, samples were taken and examined from the small intestine and corresponding lymph nodes of 84 wild ruminants: 19 red deers (Cervus elaphus) and 65 roe-deers (Capreolus capreolus). These wild ruminants originated from 44 different locations within the same district from as the infected escaped heifer. Five M. paratuberculosis strains were isolated: one strain of RFLP type B-C1 from a stag and three strains of RFLP type B-C1 and one strain of RFLP type B-C9 from roe-deer. The three wild ruminants (one stag and two roe-deer) infected with the same RFLP type B-C1 were detected in the same area as the heifer, suggesting that this was the likely infection source. However, the infection source of the roe-deer infected with strain of RFLP type B-C9 was obviously different, and the stags that escaped from the farm were purchased from an area infected with this RFLP type. In the second study carried out during 1997-1998 in the whole Czech Republic (divided into 76 districts), 718 wild ruminants were examined from 90% of the districts. M. paratuberculosis was isolated from 25 (3.5%) animals from the wild, from farms and from game parks: 7.1% of 132 red deers, 1.5% of 336 roe-deers, 3.9% of 178 fallow deers (Dama dama), and 4.2% of 48 moufflons (Ovis musimon). This study discovered three RFLP types (B-C1, D-C12 and M-C16). A surprising finding was that of M. paratuberculosis (RFLP type B-C1) infection in roe-deer and a fallow deer in their natural habitat. The infection source was determined to have originated from two imported Holstein and Limousine cattle herds infected with the same strain. In the case of a mother and daughter roe-deer infected with RFLP type M-C16 and a fallow deer infected with RFLP type D-C12, all roaming in their natural habitat, the infection source was not discovered. The highest incidence of clinically ill wild ruminants was found in farmed red deer, and no relationship was found between the RFLP type or ruminant species and clinical status of animal.

Animals↗
PubMed2000

Effect of steroidal saponin from Yucca schidigera extract on ruminal microbes.

The effects of steroidal saponins (SAP) isolated from Yucca schidigera extract on ruminal bacteria and fungi were investigated in pure culture studies. Prevotella bryantii, Ruminobacter amylophilus, Selenomonas ruminantium and Streptococcus bovis were cultured through ten 24-h transfers in ruminal fluid medium containing 0 or 25 microg SAP ml-1 (measured as smilagenin equivalents). The four strains, each non-exposed or pre-exposed to SAP, were then inoculated into medium containing 0 or 250 microgram smilagenin equivalents ml-1 and 24-h growth curves were determined. The cellulolytic ruminal bacteria Ruminococcus flavefaciens, Fibrobacter succinogenes and Rc. albus were cultured for 72 h on Whatman no. 1 filter paper in medium containing 0, 9, 90 or 180 microgram SAP ml-1 for the determination of filter paper digestion and endoglucanase activity. The ruminal bacteria differed in their responses to SAP. Steroidal saponins in the medium reduced the growth of Strep. bovis (P < 0.01 at 2, 3, 4, 5, 6 and 8 h), P. bryantii (P < 0.05 at 4, 5, 6, 8, 10 and 24 h) and Rb. amylophilus (P < 0.05 at 14 and 24 h), but the growth of S. ruminantium was enhanced (P < 0.05) at 10, 14 and 24 h. The growth curves of all four non-cellulolytic species were similar (P > 0.05) between pre-exposed and non-exposed cultures and the concentrations of total SAP and soluble (deglycosylated) SAP in the liquid fraction were unchanged (P > 0.05) over time. Steroidal saponins inhibited the digestion of filter paper by all three cellulolytic bacteria, but F. succinogenes was less (P < 0.05) sensitive to SAP and more (P < 0. 05) effective at deglycosylating SAP than were Rc. flavefaciens or Rc. albus. Transmission electron microscopy revealed that SAP altered the cell walls of the SAP-inhibited non-cellulolytic bacteria. The ruminal fungi, Neocallimastix frontalis and Piromyces rhizinflata, were cultured on filter paper in medium containing 0, 0. 45, 2.25 or 4.5 microgram SAP ml-1. Filter paper digestion by both fungi was completely inhibited by 2.25 microgram SAP ml-1. Steroidal saponins from Y. schidigera inhibit cellulolytic ruminal bacteria and fungi, but their effects on amylolytic bacteria are species dependent and similar to the effects of ionophores. As such, SAP may be useful in nutritional applications targeting starch-digesting ruminal micro-organisms.

Amyloid↗
PubMed2001

Secretory ribonucleases in the primitive ruminant chevrotain (Tragulus javanicus).

Phylogenetic analyses of secretory ribonucleases or RNases 1 have shown that gene duplication events, giving rise to three paralogous genes (pancreatic, seminal and brain RNase), occurred during the evolution of ancestral ruminants. A higher number of paralogous sequences are present in chevrotain (Tragulus javanicus), the earliest diverged taxon within the ruminants. Two pancreatic RNase sequences were identified, one encoding the pancreatic enzyme, the other encoding a pseudogene. The identity of the pancreatic enzyme was confirmed by isolation of the protein and N-terminal sequence analysis. It is the most acidic pancreatic ribonuclease identified so far. Formation of the mature enzyme requires cleavage by signal peptidase of a peptide bond between two glutamic acid residues. The seminal-type RNase gene shows features of a pseudogene, like orthologous genes in other ruminants investigated with the exception of the bovine species. The brain-type RNase gene of chevrotain is expressed in brain tissue. A hybrid gene with a pancreatic-type N-terminal and a brain-type C-terminal sequence has been identified but nothing is known about its expression. Phylogenetic analysis of RNase 1 sequences of six ruminant, three other artiodactyl and two whale species support previous findings that two gene duplications occurred in a ruminant ancestor. Three distinct groups of pancreatic, seminal-type and brain-type RNases have been identified and within each group the chevrotain sequence it the first to diverge. In taxa with duplications of the RNase gene (ruminants and camels) the gene evolved at twice as fast than in taxa in which only one gene could be demonstrated; in ruminants there was an approximately fourfold increase directly after the duplications and then a slowing in evolutionary rate.

Animals↗
PubMed1989

The evocation of rumination in sheep by the close-arterial injection of catecholamines, cholinergic drugs, autacoids and gastrointestinal hormones into the forestomach.

The effect of alpha-2 adrenoreceptor agonists, cholinergic drugs, autacoids and some gastrointestinal hormones upon the evocation of rumination in sheep when injected by close-arterial injection into the forestomach was examined. Apart from adrenaline, noradrenaline, dopamine and xylazine only one alpha-2 agonist (BHT933) evoked rumination effectively. Acetylcholine, neostigmine, the gastrointestinal hormones and the autacoids examined did not evoke rumination consistently. Tyramine did not usually evoke rumination and guanethidine injected before adrenaline did not prevent the latter from evoking rumination. The evocation of rumination by catecholamines does not appear to involve sympathetic, cholinergic or non-sympathetic non-cholinergic neurones in the enteric nervous system to activate the nervous sensory receptors involved in the reflex evocation of rumination.

Animals↗
PubMed2005

Evaluation of farm management practices as risk factors for clinical listeriosis and fecal shedding of Listeria monocytogenes in ruminants.

OBJECTIVE: To assess seasonal variation in prevalence of Listeria monocytogenes on ruminant farms and identify management practices associated with ruminant listeriosis and fecal shedding of L. monocytogenes. STUDY DESIGN: Case-control study. SAMPLE POPULATION: 2056 samples of feces, feed, soil, and water from 24 case farms with listeriosis and 28 control farms without listeriosis. PROCEDURE: Samples were collected and evaluated via bacterial culture for L. monocytogenes. Univariate associations between farm management practices and listeriosis and fecal shedding of L. monocytogenes were assessed. Multivariate models were developed to identify farm management practices associated with listeriosis and fecal shedding of L. monocytogenes. RESULTS: The prevalence of L. monocytogenes on cattle, goat, and sheep farms was seasonal, especially in fecal samples, with peak prevalence in winter. Although the prevalence of L. monocytogenes in feedstuffs from small-ruminant farms also peaked during winter, the bacterium was detected at a constant rate in cattle farm feedstuffs throughout the year. Farm management practices, animal health and hygiene, and feedstuff quality and storage were associated with ruminant listeriosis and fecal shedding of L. monocytogenes. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that the prevalence of L. monocytogenes on ruminant farms is seasonal, management practices are associated with ruminant listeriosis and fecal shedding of L. monocytogenes, and the epidemiologic features of listeriosis differ in cattle versus small ruminants. Awareness of risk factors may be used to develop control measures to reduce animal disease and introduction of L. monocytogenes into the human food chain.

Animal Husbandry↗
PubMed1990

A review of the physiological significance of hypertonic body fluids on feed intake and ruminal function: salivation, motility and microbes.

Mechanisms exist in the ruminant to detect changes in osmolality and volume of plasma during feeding to maintain fluid and electrolyte homeostasis. Feed intake during a meal can be limited by the rise in osmolality of ruminal fluid, which is sensed in the wall of the rumino-reticulum. Ruminal microbes appear to be resilient to the short-term changes in ruminal fluid tonicity, but in vitro growth rates are inhibited when the tonicity of the culture medium is increased beyond physiological levels. Although mixing contractions of the rumen are not inhibited by the normal increases in tonicity of ruminal fluid, time to first rumination is increased. This aspect of motility requires further research. The tonicity of plasma increases toward the end of a large meal as a consequence primarily of absorption of VFA and Na+ from the rumen and fluid shifts into the gut. This hypertonicity is sensed centrally to inhibit parotid secretion by a reduction in the parasympathetic stimulation to the gland. Increases in animal production may result from future research directed toward developing ways of counteracting these negative effects of hypertonicity in body fluids on feed intake and ruminal function.

Animals↗
PubMed1990

Inert plastics as indicators of physiological processes in the gastrointestinal tract of ruminants.

Various types of plastics with different physical properties have been useful in measuring rumination and passage events in the gastrointestinal tract (GIT) of ruminants. Plastic ribbons and monofilaments are available in different diameters, specific gravities and hardness and they can be cut to various lengths. Specific studies that are amenable to these materials include physical appetite control, regurgitation for rumination, passage from the rumen with or without rumination and passage through the entire GIT. Passage of particles through specific portions of the GIT can be measured in animals with various fistula preparations. The rumination of plastic ribbon in the rumen is similar to that of long forage. If the particle length is 7 cm or less, the particle can be regurgitated and produces normal rumination patterns. Movement of particles from one part of the rumen to another can be measured. Multiple sites can be studied in the same experiment by using particles of different colors. Isolating particles from ingesta or fecal residues usually starts with sieving to remove the small particles. Various subsequent separation schemes include flotation or sedimentation, air streams or acid digestion; when other methods fail, particles can be manually separated and counted. Plastic markers have several potential uses in ruminant research but they also have limitations. Because they are inert, they cannot undergo the hydration, density and size changes that occur with normal feed particles.

Animals↗
PubMed1991

Fish meal as a protein supplement in ruminant diets: a review.

Fish meal (FM) as a protein supplement in ruminant diets is presented to illustrate production responses to FM supplementation and to explain the possible factors that may affect the magnitude of these responses. Positive responses are consistently detected when FM is fed to nonruminants, but the responses when fed to ruminants have lacked consistency. Research indicates that ruminal protein degradation of FM is affected by processing factors including type and freshness of fish, addition of preservatives, stabilization of fat, type of dryer used, temperature and duration of heating, and the amount of fish solubles added back to the meal. Performance data published in the last two decades have been categorized into body weight gain and milk yield and composition. Fish meal was more effective in improving body weight gain in young than in finishing ruminants and in males than in females or castrated males. Daily gains and feed efficiencies were higher when FM supplemented medium- or poor-quality silages than when it was added to high-quality silages. No significant advantage was found for replacing protein sources that were highly ruminally degradable with FM in high-corn diets fed to growing ruminants. Milk yield and milk protein concentration were improved by FM supplementation of low-concentrate diets fed to cows in early lactation. However, milk fat percentage was negatively affected by FM supplementation. Reproduction data indicated that body gain and conception rates of high-producing cows were improved by supplementing their diets with FM during early lactation. Results suggest a significant advantage of FM supplementation to ruminant diets if the physiological status of the animal and the quality of the dietary ingredients are taken into account.

Animal Feed↗