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The aim of this study was to investigate the associations between differential somatic cell count (DSCC) and milk quality and udder health traits, and for the first time, between DSCC and milk coagulation properties and cheesemaking traits in a population of 1,264 Holstein cows reared in northern Italy. Differential somatic cell count represents the combined proportions of polymorphonuclear neutrophils plus lymphocytes (PMN-LYM) in the total somatic cell count (SCC), with macrophages (MAC) making up the remaining proportion. The milk traits investigated in this study were milk yield (MY), 8 traits related to milk composition and quality (fat, protein, casein, casein index, lactose, urea, pH, and milk conductivity), 9 milk coagulation traits [3 milk coagulation properties (MCP) and 6 curd firming (CF) traits], 7 cheesemaking traits, 3 cheese yield (CY) traits, and 4 milk nutrient recovery in the curd (REC) traits. A linear mixed model was fitted to explore the associations between SCS combined with DSCC and the aforementioned milk traits. An additional model was run, which included DSCC expressed as the PMN-LYM and MAC counts, obtained by multiplying the percentage of PMN-LYM and MAC by SCC in the milk for each cow in the data set. The unfavorable association between SCS and milk quality and technological traits was confirmed. Increased DSCC was instead associated with a linear increase in MY, casein index, and lactose proportion and a linear decrease in milk fat and milk conductivity. Accordingly, DSCC was favorably associated with all MCP and CF traits (with the exception of the time needed to achieve maximum, CF), particularly with rennet coagulation time, and it always displayed linear relationships. Differential somatic cell count was also positively associated with the recovery of milk nutrients in the curd (protein, fat, and energy), which increased linearly with increasing DSCC. The PMN-LYM count was rarely associated with milk traits, even though the pattern observed confirmed the results obtained when both SCS and DSCC were included in the model. The MAC count, however, showed the opposite pattern: MY, casein index, and lactose percentage decreased and milk conductivity increased with an increasing MAC count. No significant association was found between PMN-LYM count and MCP, CF, CY, and REC traits, whereas MAC count was unfavorably associated with MCP, CF traits, some CY traits, and all REC traits. Our results showed that the combined information derived from SCS and DSCC might be useful to monitor milk quality and cheesemaking-related traits.

Metabolic disorders, including hepatic lipidosis and ketosis, severely affect animal health status and welfare with a large economic burden in dairy herds. The gold standard for diagnosing hepatic lipidosis is the liver biopsy, which is impractical and invasive for the screening at farm level. Ultrasound (US) imaging is a promising technique for identifying liver dysfunction, but standardized specifications in physiological conditions are needed. Herein, we described the features of four US measurements, namely the liver predicted triacylglycerol (pTAG) content, liver depth (LD), and portal vein area (PVA) and depth (PVD) and we investigated their associations with a set of hematochemical (HC) indicators in 342 clinically healthy Holstein Friesian dairy cows. Liver pTAG content was negatively associated with hematocrit and positively with globulin, whereas PVA was negatively associated with thiol group levels, and LD positively with ceruloplasmin. We found significant interactions between some HC parameters and parity: in particular, creatinine, thiol groups and globulin for PVA, and aspartate aminotransferase, paraoxonase and ceruloplasmin for PVD. This study offers new insights on variations in liver function occurring after calving and pave the way for the potential use of minimally invasive techniques for prompt detection of metabolic disorders in dairy herds.

Essential oils (EOs) are generally considered as an alternative to antibiotics because of their antimicrobial properties. Despite their vast variety, their volatile nature poses hindrance on their use in animal feeds, which demands a high degree of stability. This study aimed at testing the susceptibility of three EOs (mixtures of EOs based on cinnamaldehyde, named Olistat-Cyn, Olistat-G, and Olistat-P) in two forms (free: fEOs, and microencapsulated: mEOs) to in vitro ruminal degradation using the Ankom DaisyII technique. The microencapsulation was made using a matrix based on vegetable hydrogenated fatty acids. Compared to the fEOs, which were completely degraded within 48 h of in vitro incubation, the mEOs showed a low ruminal disappearance. In comparison to the fermentation profile at 0 h, Olistat-G significantly decreased the pH and the total protozoa number after 48 h, while the total VFAs increased. However, the other EOs (Olistat-Cyn and Olistat-P) had no effect on the rumen fermentation parameters. In conclusion, the protection of EOs from ruminal degradation by microencapsulation was found to be very effective to ensure rumen by-pass. Among the EOs, Olistat-G was capable of changing rumen fermentation, potentially reducing methane emissions.

Mastitis is one of the most prevalent diseases in dairy cattle and is the cause of considerable economic losses. Alongside somatic cell count (SCC), differential somatic cell count (DSCC) has been recently introduced as a new indicator of intramammary infection. The DSCC is expressed as a count or a proportion (%) of polymorphonuclear neutrophils plus lymphocytes (PMN-LYM) in milk somatic cells. These numbers are complemented to total somatic cell count or to 100 by macrophages (MAC). The aim of this study was to investigate the genetic variation and heritability of DSCC, and its correlation with milk composition, udder health indicators, milk composition, and technological traits in Holstein cattle. Data used in the analysis consisted in single test-day records from 2,488 Holstein cows reared in 36 herds located in northern Italy. Fourier-transform infrared (FTIR) spectroscopy was used to predict missing information for some milk coagulation and cheese-making traits, to increase sample size and improve estimation of the genetic parameters. Bayesian animal models were implemented via Gibbs sampling. Marginal posterior means of the heritability estimates were 0.13 for somatic cell score (SCS); 0.11 for DSCC, MAC proportion, and MAC count; and 0.10 for PMN-LYM count. Posterior means of additive genetic correlations between SCS and milk composition and udder health were low to moderate and unfavorable. All the relevant genetic correlations between the SCC traits considered and the milk traits (composition, coagulation, cheese yield and nutrients recovery) were unfavorable. The SCS showed genetic correlations of -0.30 with the milk protein proportion, -0.56 with the lactose proportion and -0.52 with the casein index. In the case of milk technological traits, SCS showed genetic correlations of 0.38 with curd firming rate (k20), 0.45 with rennet coagulation time estimated using the curd firming over time equation (RCTeq), -0.39 with asymptotic potential curd firmness, -0.26 with maximum curd firmness (CFmax), and of -0.31 with protein recovery in the curd. Differential somatic cell count expressed as proportion was correlated with SCS (0.60) but had only 2 moderate genetic correlations with milk traits: with lactose (-0.32) and CFmax (-0.33). The SCS was highly correlated with the log PMN-LYM count (0.79) and with the log MAC count (0.69). The 2 latter traits were correlated with several milk traits: fat (-0.38 and -0.43 with PMN-LYM and MAC counts, respectively), lactose percentage (-0.40 and -0.46), RCTeq (0.53 and 0.41), tmax (0.38 and 0.48). Log MAC count was correlated with k20 (+0.34), and log PMN-LYM count was correlated with CFmax (-0.26) and weight of water curd as percentage of weight of milk processed (-0.26). The results obtained offer new insights into the relationships between the indicators of udder health and the milk technological traits in Holstein cows.

Garlic and garlic components have recently been proposed as ruminal activity modulators to reduce the enteric methane emissions of ruminants, but little is known of their influence on milk coagulation properties, nutrient recovery, cheese yield, and sensorial and rheological characteristics of milk and cheese. The present study assessed the effects of garlic and diallyl sulfide supplements on dry matter intake (DMI), productive performance, milk coagulation properties, cheese yield, milk and cheese sensory profiles, and rheological characteristics. Four dairy cows were fed a total mixed ration either alone (control) or supplemented with 100 or 400 g/d of garlic cloves or 2 g/d of diallyl sulfide in 4 consecutive experimental periods in a 4 × 4 Latin square design. The diallyl sulfide dose was established to provide approximately the same amount of allyl thiosulfinate compounds as 100 g of fresh garlic cloves. The total mixed ration was composed of 0.29 corn silage, 0.23 corn-barley mixture, 0.17 sunflower-soybean mixture, 0.12 alfalfa hay, 0.12 grass hay, 0.04 sugar beet pulp, and 0.02 other additives, and contained 0.253 starch, 0.130 crude protein, and 0.375 neutral detergent fiber, on a dry matter basis. Each experimental period consisted of 7 d of transition and 14 d of treatment. On d 18 and 21 of each period, milk samples (10 L) were collected from each cow for chemical analysis and cheese-making. The organoleptic properties of the milk and 63-d-ripened cheeses were assessed by a panel of 7 trained sensory evaluators. The experimental treatments had no effects on DMI, milk yield, feed efficiency (milk yield/DMI), milk coagulation properties, nutrient recovery, or cheese yield. Garlic-like aroma, taste, and flavor of milk and cheese were significantly influenced by the treatments, particularly the highest dose of garlic cloves, and we found close exponential relationships between milk and cheese for garlic-like aroma (R2 = 0.87) and garlic-like flavor (R2 = 0.79). Diallyl sulfide and 400 g/d of garlic cloves resulted in lower pH, shear force, and shear work of ripened cheeses compared with the other treatments. Garlic cloves and diallyl sulfide had opposite effects on cheese color indices. We conclude that adding 400 g/d of garlic to the feed of lactating dairy cows highly influences the sensory and rheological characteristics of cheese.

A shortage in crude protein (CP) and supplementation of conjugated linoleic acids (CLA) in the diets of dairy cows could improve the dairy industry's ecological footprint and the nutritional value of milk, but it is not known what effect such a strategy might have on the aroma profiles of dairy products. The aim of this work was to study the effects of reducing the dietary CP content (from 150 to 123 g/kg of dry matter), with or without a supply of rumen-protected CLA (7.9 g/d C18:2 cis-9,trans-11 and 7.7 g/d C18:2 trans-10,cis-12), on the volatile organic compound (VOC) profile of cheeses ripened for 3 mo. Twenty mid-lactation Holstein-Friesian cows were reared in 4 pens (5 to a pen), and fed 4 different experimental diets over 4 periods of 3 wk each, following a 4 × 4 Latin square design. Twice in each period, 10-L milk samples were taken from each group and used to produce 32 cheeses, which we then analyzed for VOC by solid-phase microextraction and gas chromatography-mass spectrometry. We detected 48 VOC belonging to 10 chemical classes (11 alcohols, 8 ketones, 8 esters, 7 acids, 4 aldehydes, 4 sulfurs, 2 lactones, 2 phenolic, 1 monoterpene, 1 hydrocarbon); these were expressed as concentrations in cheese (quantitative data) or as proportions of total VOC (qualitative data). The results of mixed model analysis showed that the majority of VOC families and individual VOC in ripened cheese were affected by the dietary treatments: CP shortage depressed the concentrations of volatile aldehydes and increased the proportions of some esters and limonene, whereas CLA increased the concentration of total VOC, particularly several acids and esters, and decreased the proportions of ketones and phenolic compounds. The interaction between dietary CP and CLA affected the proportions of alcohols and acids. We performed a factor analysis to extract 5 latent explanatory variables from the individual VOC, which represented 79% of total VOC variance for the quantitative data and 78% for the qualitative data. Addition of CLA decreased the first qualitative factor (the "base aroma" of cheese, explaining 44% of total variance), whereas CP reduction increased the second quantitative factor ("ethyl esters," 15% of total variance) and the third qualitative factor ("butan-," 9% of total variance). In summary, the VOC profile of ripened cheese was heavily influenced by CP content and CLA supplementation in the diets of dairy cows, but the effect on sensorial properties of cheese is also worth considering.

We used 20 mid-lactating Holstein cows, housed in 4 pens according to a Latin square design, to evaluate the effects of dietary protein restriction (crude protein: 12.3 vs. 15.0% dry matter) and conjugated linoleic acid supplementation (CLA: 6.34 g/d of C18:2cis-9,trans-11 and 6.14 g/d of C18:2trans-10,cis-12) on milk composition, coagulation, curd firming and syneresis modeling, and cheese yield and quality (96 small cheeses). Dietary crude protein restriction, suggested as a way to reduce N excretion in farming, caused a reduction in milk protein content (-4%,), milk casein (-3.8%), lactose (-1%), cheese soluble protein (-16.8%), and the cheese maturation index (-15%), and a correlated increase in cheese fat content (+7.5%) and the fat to protein ratio (+18%). A modest reduction (-0.9%) in milk fat recovery in the curd did not affect cheese yield. The addition of CLA to the cows' diet, suggested as a way to improve N use efficiency and the nutritional value of dairy products, caused substantial alterations to the milk composition, cheese-making process, and cheese quality. The CLA reduced the fat (-12.3%), protein (-2%), casein (-2.2%), lactose (-1.0), and total solids (-4%) contents of milk, tended to delay coagulation, and weakened curd firming. The CLA reduced the fresh cheese yield (-7.5%) and cheese solids (-8.2%) because of the lower nutrient content of the milk, but also because of a lower recovery of milk protein in the curd (-0.9%) and lower total solids (-4.5%). It also reduced the fat content in the ripened cheese (-11.8%), as well as the fat to protein ratio (-19.4%) as a result of having increased the protein content (+9.3%). Last, it increased the lightness of the paste of the ripened cheeses (+3.3%), and especially the shear force (+16.3%). Dietary crude protein restriction, and CLA addition in particular, substantially altered the milk composition, cheese-making process, and cheese quality, and therefore needs to be carefully evaluated. Further studies are required to shed light on the causes of these modifications.

The utilization of animal donors of rumen fluid for laboratory experiments can raise ethical concerns, and alternatives to the collection of rumen fluids from live animals are urgently requested. The aim of this study was to compare the fresh rumen fluid (collected at slaughter, W) with that obtained from a continuous fermenter (RCF) and three methods of rumen fluid preservation (refrigeration, R, chilling, C, and freeze-drying, FD). The fermentability of different inoculum was evaluated by three in vitro tests (neutral detergent fiber (NDF) and crude protein (CP) degradability and gas production, NDFd, RDP and GP, respectively) using six feeds as substrates. Despite the two types of inoculum differed in terms of metabolites and microbiota concentration, the differences in vitro fermentability between the two liquids were less pronounced than expected (&minus, 15 and 20% for NDFd and GP when the liquid of fermenter was used and no differences for RDP). Within each in vitro test, the data obtained from rumen and from fermenter liquids were highly correlated for the six feeds, as well as between W and R (r: 0.837&ndash, 0.985, p &lt, 0.01). The low fermentative capacity was found for C and, particularly, FD for liquids. RCF could be used to generate inoculum for in vitro purposes and short-term refrigeration is a valuable practice to manage inoculum.

This study explored the effects of one ionophore compound (monensin) and four pure extracts (limonene, allyl sulfide, cinnamaldehyde, and eugenol) on in vitro rumen fermentation and methane (CH 4 ) production of a commercial diet for dairy cows. Four consecutive incubations at 24 h were conducted using an automated gas production (GP) system, where gas was vented at fixed pressure. Bottles (317 ml) were filled with 1.0 ± 0.010 g of diet and 150 ml of buffered rumen fluid. Additives were added at two dosages: 0.015 (low) or 0.030 mg/g of diet (high) for monensin, 3 (low) or 30 mg/g of diet (high) for the pure extracts. In each incubation, eleven treatments were tested in 3 replications: a control (CTR; bottles without additive), plus 5 additives × 2 dosages. Twelve bottles (3/run), containing only the buffered rumen fluid, were included as blanks. At the end of each incubation, gas samples were collected from bottle headspace and analyzed for CH 4 . The proportion of CH 4 lost with venting was calculated. Fermentation fluids were analyzed for aNDF (NDFd) and true DM (TDMd) degradability, ammonia N, and VFA. Data were analyzed using a model considering the treatment as fixed factor and run as a random factor. Additives were ineffective at the low dosage. Compared to CTR, the high dosage of monensin reduced NDFd (−17%), TDMd (−3%), and CH 4 produced per g of truly degraded DM (−19%). Acetate was reduced (−13%) in favor of propionate (+25%), but the total VFA production did not change. Compared to CTR, the high dosage of limonene reduced NDFd (−66%), TDMd (−14%), GP (−25%) and CH 4 production (−34%) per g of truly degraded DM, and the total production of VFA (−25%), acetate (−31%), and propionate (−13%) (P 4 production (−32%) per g of truly degraded DM, the total VFA (−12%) and acetate production (−24%), but increased that of propionate (+15%). The high dosage of cinnamaldehyde did not influence NDFd, TDMd or the total VFA production, reduced GP (−10%), CH 4 production (−12%) per g of truly degraded DM and acetate production (−14%), but increased that of propionate (+9%). The high dosage of eugenol reduced only NDFd (−18%) and TDMd (−3%). In conclusion, the most promising results were observed for the high dosage of cinnamaldehyde, as in vitro CH 4 production was reduced without effects on degradability and VFA production. However, these effects should be confirmed using dosages and experimental conditions proper of in vivo trials.

The aim of this study was to perform genetic, genome-wide association (GWAS), and gene-set enrichment analyses with latent variables related to milk fatty acid profile (i.e., fatty acids factor scores; FAF), milk composition, and udder health in a cohort of 1,158 Italian Brown Swiss cows. The phenotypes under study were 12 FAF previously identified through factor analysis and classified as follows: de novo FA (F1), branched-chain FA-milk yield (F2), biohydrogenation (F3), long-chain fatty acids (F4), desaturation (F5), short-chain fatty acids (F6), milk protein and fat contents (F7), odd fatty acids (F8), conjugated linoleic acids (F9), linoleic acid (F10), udder health (F11) and vaccelenic acid (F12). (Co)variance components were estimated for factor scores using a Bayesian linear animal model via Gibbs sampling. The animals were genotyped with the Illumina BovineSNP50 BeadChip v.2 (Illumina Inc., San Diego, CA). A single marker regression model was fitted for GWAS analysis. The gene-set enrichment analysis was run on the GWAS results using the Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes pathway databases to identify the ontologies and pathways associated with the FAF. Marginal posterior means of the heritabilities of the aforementioned FAF ranged from 0.048 for F12 to 0.310 for F5. Factors F1 and F6 had the highest number of relevant genetic correlations with the other traits. The genomic analysis detected a total of 39 significant SNP located on 17 Bos taurus autosomes. All latent variables produced signals except for F2 and F10. The traits with the highest number of significant associations were F11 (17) and F12 (7). Gene-set enrichment analyses identified significant pathways (false discovery rate 5%) for F3 and F7. In particular, systemic lupus erythematosus was enriched for F3, whereas the MAPK (mitogen-activated protein kinase) signaling pathway was overrepresented for F7. The results support the existence of important and exploitable genetic and genomic variation in these latent explanatory phenotypes. Information acquired might be exploited in selection programs and when designing further studies on the role of the putative candidate genes identified in the regulation of milk composition and udder health.

We investigated the influence of rumen-protected conjugated linoleic acid (rpCLA) on growth performances, and carcass and meat quality traits in beef. Twenty-four young bulls and 30 heifers obtained from double-muscled beef sires and dairy cows were fed a low-protein ration (110 g/kg DM of crude protein) supplemented with 0, 8 or 80 g/d of a commercial rpCLA product. The animals were monthly weighed and scored for body muscularity and fatness. Blood samples were collected after 140 days on feed. Animals were slaughtered when they reached average in vivo fatness scores of around 2.5 (heifers) and 2.0 (bulls) points respectively. At slaughter, carcasses, various organs and parts of the gastrointestinal tract were weighed; the 5th rib was dissected and its tissue and muscle chemical composition was determined. The rpCLA had little influence on growth performance but decreased the blood urea content by 28% (p < 0.01). The rpCLA × sex interactions for daily gain (p < 0.05), conformation scores (p < 0.01), and blood creatinine content (p < 0.05) suggest that males were more responsive to rpCLA than females when fed a low-protein ration, probably because of the metabolic protein-sparing effect of CLA. Only slight differences were observed in carcass weight and quality at slaughter. The results indicate that the response of beef cattle to rpCLA is dependent on sex or on their propensity for lean and fat accretion. It is also possible that counteracting feedback mechanisms compensate for the influence of rpCLA administration over the course of growth.

We developed a procedure to estimate the release of nutrients into the environment on Alpine dairy farms and applied it to a sample of 564 farms in the Province of Trento (north-eastern Italy) as a case study. Farm data (geographical location, herd size, milk production and quality, reproductive events, land use) were gathered from institutional databases and merged. Information on the formulation of the ration was obtained from farm visits. The farms fell into 4 groups: traditional with summer transhumance to highland pastures (T-ALP, 51%), traditional without transhumance (T-noALP, 24%), traditional using silage (T-S, 5%), and modern (MOD, 20%). The model predicted N and P excretion from cows and heifers on a farm basis. The N in manure was computed from total N excreted, assuming a 28% of N loss due to volatilisation. A cow unit was defined as the cow and its share of replacement heifer. The average dietary N content of the lactating cows ranged from 20 to 30 g/kg DM, while on-farm N excretion ranged from 90 to 190 kg/year per cow unit; the modern farms had the highest average value (137 kg), the T-ALP farms the lowest (106 kg). Average P excretion ranged from 10 to 40 kg/year/cow unit. The on-farm N and P in manure per unit of milk decreased asymptotically with increasing cow productivity, from 25 to 19 and from 4.1 to 2.8 g/kg milk, respectively. The modern farms had the greatest amounts of N and P in manure per unit of agricultural land (260 and 51 kg/ha, respectively), the T-ALP farms the lowest (161 and 37 kg/ha, respectively). Within system, there was a huge variation among farms in the N and P load per unit of agricultural land, which was largely explained by the number of cow units per ha and by nutrient excretion per cow unit, but not by herd size or cow productivity. Within dairy system, the N and P contents of the rations for lactating cows were weakly related to the daily milk yield, but strongly related to the annual excretion of the nutrient per cow unit. The farm N loads were below the legal thresholds (340 kg N/ha per year), but the geographical distribution of the loads indicated two critical areas due to farm density.

In pursuit of novel strategies aimed to promote animal production while exploiting agricultural residues, using the dromedarycamel rumen fluid degradation capabilities combined with a gas production (GP) technique approach, we investigated the in vitrokinetic parameters and some physical and chemical characteristics of three agro-industrial byproducts (AIBP) and their mixtureswith three roughages. Chemical composition, buffering capacity, apparent degradability, pH, and in vitro GP kinetic parameters wereevaluated for citrus pulp, tomato peels, apple pomace, their mixtures (50:50 % DM basis) with milk thistle, crown daisy, and polyphytehay. GP of AIBP ranged from 200 to 240 mL/g DM. Roughages produced significantly less gas whereas mixtures gave intermediateamounts of gas. Gas from AIBP evolved with significantly (P < 0.05) shorter lag time (0.33 h) compared with roughages and mixtures.Mixing roughages with AIBP significantly (P < 0.05) increased the initial and final pH. The buffering capacity significantly increasedwith some mixtures and decreased with some others. In conclusion, ruminal fluid from slaughtered dromedaries, like the conventionalbovine inoculum, fermented the major plant polymers and can be used in in vitro degradability trials. Rapidly fermentable AIPB mixedwith roughages can improve some nutritional aspects, providing dietary fiber and correcting some in vitro kinetic parameters.

In this study, 2-dimensional gas chromatography (GC × GC) was used to obtain a detailed fatty acid (FA) profile of sheep milk and to evaluate the effects of a rumen-protected conjugated linoleic acid (rpCLA) supply, breed, days in milk (DIM), sampling period, and number of lambs suckling on the FA profile. Twenty-four ewes, from 3 autochthonous breeds of the Veneto Alps (Brogna, Foza, and Lamon), were housed in 6 pens (2 pens/breed), according to DIM (38 ± 23 d) and body weight (61 ± 13 kg). The ewes and their offspring of 3 pens (1 pen/breed) were fed ad libitum a total mixed ration (control), and the other animals received the same diet supplemented with 12 g/d per ewe, plus 4 g/d for each lamb older than 30 d, of an rpCLA mixture. The study lasted 63 d. Two composite milk samples for each ewe were prepared during the first and second months of the trial. The pooled milk samples were analyzed in duplicate for FA profile by 2-dimensional gas chromatography, which allowed us to obtain a detailed FA profile of sheep milk, with 170 different FA detected, including many that were present in small concentrations. The milk relative proportions of individual FA, groups of FA, or FA indices were analyzed by PROC MIXED of SAS (SAS Institute Inc., Cary, NC), considering diet, breed, DIM, and sampling period as sources of variation. The random effect of animal was used to test diet, breed, and DIM, whereas the effects of period were tested on the residual. Breed had a small influence on milk FA profile, mainly on branched- and odd-chain FA. Within breed, animal repeatability for the relative proportions of milk FA was notable for almost all monounsaturated FA and for saturated FA with 14 to 19 carbon atoms, except C16:0, and less so for polyunsaturated FA. The inclusion of rpCLA (CLA cis-9,trans-11 and CLA trans-10,cis-12) increased the presence of the same CLA isomers in the milk as well as that of CLA trans-9,trans-11, and decreased the proportions of de novo-synthesized short-chain FA. From a cluster analysis based on the matrix of correlation coefficients among all FA relative proportions, 3 main FA groups were observed: the first included mainly odd- or branched-chain saturated FA, C18:0, C16:0 and CLA trans-10,cis-12; the second included monounsaturated FA or polyunsaturated FA with 16 to 20 carbons, CLA cis-9,trans-11, and CLA trans-9,trans-11; and the third included short- to medium-chain saturated FA, polyunsaturated FA with 2 to 5 double bonds, and 3 CLA isomers not affected by rpCLA addition (CLA trans-11,cis-13, CLA cis-9,cis-11, and CLA cis-10,cis-12).

Little is known about the influence of dietary crude protein (CP) restriction and rumen-protected conjugated linoleic acid (rpCLA) supply on digestibility and metabolism of nutrients in dairy cows. This study investigated the effect of low dietary CP level combined with rpCLA supply on FA secretion into milk and excretion via feces in dairy cows. Twenty Friesian cows were involved in a 4 × 4 Latin square design over 3-week periods. Cows were fed 4 different rations based on 2 dietary CP levels (150 and 123 g/kg dry matter of CP), each one with or without the addition of a 80 g/d supplement of rpCLA. Feed, feces and milk samples were analyzed for their fatty acid content (FA) and data were used to calculate apparent FA transfer as the ratios between the daily FA secretion in milk, or excretion in feces, and intake. Dietary CP restriction had little influence on apparent FA transfer from the feed to the feces and the milk, but slightly increased the apparent transfer to the milk of 14:0iso (P = 0.031) and 15:0iso (P = 0.006), and tended to increase transfer of other branched FAs of microbial origin, i.e. 15:0anteiso (P = 0.06), 16:0iso (P = 0.06) and 17:0iso (P = 0.07). The rpCLA supply lowered the secretion/intake ratio of total FAs in the milk (P = 0.02), particularly those with the shortest chains and with even numbers of carbons, but had no effect on apparent transfer of branched and odd FAs of microbial origin. The rpCLA supply greatly reduced (P

Aim of this study was to compare three methods for determining fatty acid (FA) profiles in ruminant feces by GC. The first method ( J ) was based on a mild acid–base treatment directly performed on the dry fecal samples, completing in one step hydrolysis, extraction and methylation of FA. The second method ( J EE ) was based on acid hydrolysis followed by an accelerated solvent extraction (ASE) of ether extract (EE) and by a mild acid–base catalyzed methylation of FA. The third method ( C EE ) was based on an acid hydrolysis followed by ASE of EE and by an acid catalyzed methylation of FA ( C EE ). The experimental design involved the fecal samples of 9 bulls fed a total mixed ration supplemented with 0, 8 or 80 g/d of rumen protected CLA (rpCLA; 3 bulls/dose). Feces collected from these bulls were analyzed, by GC, in triplicates by each method expressing FA contents as mg/g DM. The repeatability of FA and CLA measurements of each method was determined. For the content of CLA isomers, the methods presented heteroscedastic residual variances and, thus, were compared by linear regression. Within method, fecal contents of CLA were regressed against the rpCLA dose. The F -test was employed to test the significance of any slope that deviated from unity and any intercept that was different from zero. There were no differences among methods for the total amount of FA extracted, which averaged 24.55 mg/g DM. The J method was the most repeatable method for most single FA, and for the sums of SFA, MUFA and PUFA. The two EE-methods evidenced for C18:2 c 9, t 11 CLA and C18:2 t 10, c 12 CLA linear relationships with slopes and intercepts close to 1 and 0, respectively, whereas the relationships of J EE and C EE with J had slopes lower than unity. With increasing rpCLA dosage the EE-based methods provided lower increase of fecal contents of C18:2 c 9, t 11 CLA and of C18:2 t 10, c 12 CLA isomers and a higher C18:2 t 9, t 11 CLA content than J , probably as a result of a modification of cis-trans isomerism caused by acid hydrolysis and ASE. The J method should be preferred as it provides more repeatable measures of the fecal FA profiles and because it causes a lower shift in CLA isomer composition with respect to procedures based on acid hydrolysis and ASE.

The tissue-specific response to rumen-protected conjugated linoleic acid supply (rpCLA) of liver, two muscles, and three adipose tissues of heavy lambs was studied. Twenty-four lambs, 8 months old, divided into 4 groups of 6, were fed at libitum on a ration supplemented without or with a mixture of rpCLA. Silica and hydrogenated soybean oil was the rpCLA coating matrix. The lambs were slaughtered at 11 months of age. Tissues were collected and analyzed for their FA profiles. The dietary rpCLA supplement had no influence on carcass fatness nor on the fat content of the liver and tissues and had little influence on the FA profiles of these tissues. In the adipose tissues, rpCLA increased the proportions of saturated FAs, 18:0 and 18:2t10c12, and decreased the proportions of monounsaturated FAs in the adipose tissues. In muscles, the effects were the opposite. The results suggest that Δ9 desaturase activity is inhibited by the rpCLA mixture in adipose tissues to a greater extent than in the other tissues.

The aim of this study was to investigate the consequences of reducing the dietary crude protein content, with or without a supply of protected conjugated linoleic acid (CLA), on the milk fatty acid (FA) yield and recovery in 90d ripened cheese. Twenty mid-lactation Friesian dairy cows were reared for 4 periods of 3wk each in groups of 5, following a 4×4 Latin square design. Cows were fed 4 different rations, consisting of a combination of the 2 dietary crude protein levels [150 (CP15) or 123 (CP12) g of crude protein/kg of dry matter], with or without a conjugated linoleic acid supply (80g/d, providing 5.57 and 5.40g/d of C18:2 cis-9,trans-11 and C18:2 trans-10,cis-12, respectively). Milk yield was recorded. Twice in each period, milk samples were analyzed for protein, fat, and lactose content, and 10 L milk samples (pooled by group) were processed to produce 96 cheeses, which were ripened for 90d. Milk and cheese fat were analyzed for their FA profiles. Milk and cheese FA were expressed as daily yields and relative proportions, and nutrient recoveries were computed. Dietary crude protein reduction had small or no effects on the yield and relative presence of FA in milk and cheese, except for a small increase in mid-chain branched saturated fatty acids. The CLA supply strongly reduced the yield of various categories of FA, and had major effects on short-chain FA of de novo synthesis, leading to changes in the relative proportions of the various FA in milk and cheese. The addition of CLA tended to reduce uniformly the recovery of all milk constituents and of short-, medium-, and long-chain FA groups, but we observed large differences among individual FA with apparent recoveries ranging between 640 and 1,710g/kg. The highest recoveries were found for polyunsaturated long-chain FA, the lowest for saturated or monounsaturated short- or medium-chain FA. A notable rearrangement of these FA components, particularly the minor ones, took place during ripening.

Effects of diets differing in crude protein (CP) concentrations, top-dressed or not with 80 g/d of rumen-protected conjugated linoleic acid (rpCLA), on N efficiency of double muscled (DBM) Piemontese bulls were studied using four experimental diets being: high CP, HP; high CP plus rpCLA, HP rpCLA ; low CP, LP; low CP plus rpCLA, LP rpCLA . The HP diets (145 g/kg DM of CP) were similar those used commercially and the LP diets (108 g/kg DM of CP) were used to evaluate effects of lower dietary CP levels on intake, digestibility and body retention of nutrients, as well as N excretion. Forty-eight young bulls (237 ± 24.4 kg body weight (BW)), housed in 12 pens were fed one of the four experimental diets. Bulls were slaughtered at 668 ± 56.2 kg BW, after 332 days on their diet. Dry matter intake was measured daily on a pen basis and bulls were individually weighed monthly. Blood, rumen fluid and faecal samples were collected from each bull at 63, 179 and 283 days. Empty body composition at the start and the end of the feeding period was estimated using equations developed on DBM bulls and from the composition of the 5th rib collected at slaughter. Nitrogen balance was computed using a mass balance approach. Lowering of the diet CP level reduced both blood urea N (P

The true dry matter (DM) digestibility (TDMd) and metabolizable energy (ME) contents of feeds are frequently assessed from the amount of digestible neutral detergent fibre (dNDF) measured in situ or in vitro after a fixed time of incubation using a theoretical summative approach. Feed ME content can also be predicted from the gas produced after 24 h of in vitro incubation (GP24) and its chemical composition. Aims of this study were to evaluate the validity of reducing the in situ incubation time from 48 to 24 h for determining TDMd and to study the relationship between the ME values estimated from dNDF and from GP24. Eleven feeds (aNDF: 101–768 g/kg DM) were simultaneously incubated in the rumen of two cows for 24 and 48 h with two replications. Following National Research Council (NRC) guidelines, dNDF measured after 24 and 48 h of incubation was used to compute true DM digestibility (TDMd24 and TDMd48, respectively) and ME based on 48 h (MENRC). From the same feeds incubated in vitro, GP24 was measured by an automated GP system with 4 replications. The in situ and the in vitro incubations were repeated twice. Estimates of ME from GP24 were computed using the Hohenheim (MEMenke) and UC Davis (MEUCD) equations developed using in vivo digestibility measurements. The MENRC, MEMenke and MEUCD estimates were compared by regression. The repeatability of TDMd24 and TDMd48 was comparable (SED = 12 g/kg DM) and these values were related with a RMSE of only 21.5 g/kg DM suggesting that, for in situ evaluations, the incubation time can be reduced from 48 to 24 h. The measures of GP24 and TDMd48 were also well correlated (R2 = 0.97), but only for feeds with

The effects of low-protein (LP) diets and rumen-protected CLA on DMI, ADG, carcass traits, and health status of double-muscled Piemontese young bulls were investigated. Forty-eight bull calves (BW = 237 ± 24 kg) were divided in 4 groups and housed in 12 fully slatted pens. Bulls were fed 2 diets differing in CP density (high-protein (HP) diet: CP = 145 g/kg of DM; LP diet: CP = 108 g/kg of DM) and top-dressed with 80 g/d of rumen-protected CLA or 65 g/d of hydrogenated soybean oil. Orts were collected weekly and feed intake was estimated on a pen basis, with 3 replicated pens for each treatment. Each bull was weighed monthly and examined for alterations of the locomotion system by using the locomotion score as an index of lameness and by counting the number of swollen joints. Carcass quality traits were measured at slaughter, after a feeding period of 332 d. Compared with HP, LP reduced ADG only during the first 4 mo of the trial (1.30 vs. 1.53 kg/d, P = 0.003). However, be- cause of compensatory growth, over the whole trial, no significant effects attributable to CP or to additive were found on final BW (668 kg), ADG (1.19 kg/d), DMI (8.50 or 86 g/d per kg of BW 0.75 ), dressing percentage (67.3%), carcass conformation (5.2 points), and carcass fat covering (1.87 points). Feed efficiency was affected by a CP × additive interaction (P = 0.030), with CLA improving feed efficiency when added to the LP diets, whereas feed efficiency was reduced with the HP diets. The addition of both LP and CLA reduced the number of bulls presenting swollen joints (P = 0.001), and LP improved the locomotion score (P = 0.021) compared with HP. It was concluded that 10.8 g/kg of CP density in the diet is sufficient for double-muscled Piemontese bulls. The reduction in CP density from 145 to 108 g/ kg of DM, in addition to reducing the feeding cost, allows a strong reduction in N consumption without negative consequences on growth performance and car- cass traits.

The aim was to evaluate the effect of low-protein (LP) or low-amino acid diets on digestibility, energy and nitrogen (N) utilisation in 2 genetic groups (GG) of pigs (129±11 kg BW). Duroc×Large White (A) pigs were chosen to represent a traditional GG for ham production, and Danbred Duroc (D) pigs to represent a GG with fast growing rate and high carcass lean yield. Dietary treatments: a conventional diet (CONV) containing 13.2% CP, and two LP diets, one with LP (10.4%) and low essential AA (LP1), the second with LP (9.7%) and high essential AA (LP2). Compared to CONV, LP2 had the same essential AA content per unit feed, while LP1 the same essential AA content per unit CP. Feed was restricted (DMI=6.8% BW0.75). Four consecutive digestibility/balances periods were conducted with 24 barrows, 12 A and 12 D. Metabolic cages and respiration chambers were used. No significant difference between diets was registered for digestibility. Nitrogen excreted: 41.3, 33.4 and 29.0 g/d (P=0.009), for CONV, LP1 and LP2 diets, respectively. Nitrogen retention was similar between the diets. Heat production (HP) was the lowest for LP diets. There was a tendency (P=0.079) for a lower energy digestibility in D group. The D pigs also had a higher HP and hence a lower retained energy in comparison with the A pigs. In conclusion: it is possible to reduce N excretion using very LP diets and LP-low AA diets; Danbred GG have a higher heat production and a lower energy retention than A pigs.

An experiment was conducted to examine differences in the in vitro fermentability of four carbohydrate-rich feed ingredients and two weaning piglet diets with and without these ingredients, using both the ileal contents and the faeces of unweaned piglets as inocula. In the first part of the experiment, cumulative gas production was measured over time, using faecal inocula mixed from nine specially raised crossbred piglets (no creep feed or antibiotics) at 3 weeks of age. Inulin, lactulose, unmolassed sugar beet pulp, wheat starch and the two diets were used as substrates and fermented in vitro for 72 h. Gas production was measured as an indicator of the kinetics of fermentation. Fermentation end-products, including volatile fatty acids and ammonia, and organic matter loss, were also measured. For the fermentations of feed ingredients, samples were also collected for polymerase chain reaction/denaturing gradient gel electrophoresis analyses initially and after the fermentation process, to study changes in the composition of the bacterial community. This procedure was repeated 1 week later, using ileal contents from the same piglets as inoculum. There were significant differences between the inocula, in terms of both overall fermentation characteristics and composition and between the substrates. There was also a significant interaction between inocula and substrates, which suggests that there were potentially important differences in the microbial activity occurring in these two areas of the gastrointestinal tract (GIT). For the two diets, one with and one without addition of these fermentable ingredients, there were significant differences in terms of the kinetics, but less so in terms of the end-products of fermentation. It was concluded that inocula from both the small and large intestine should be used to obtain a more accurate assessment of potential feed ingredients which will stimulate fermentation in the piglet GIT. Copyright © 2005 Society of Chemical Industry

The objective of this experiment is to evaluate the changes of particle size distribution and chemical composition of the total mixed ration (TMR) based on hay as the main forage component (“dry” TMR) and distributed once (7.00 am) or twice (7.00 am and 1.00 pm) daily to 32 lactating cows. The trial was divided in two periods of 14 days each. Diet (DM=53.7%) was formulated in order to assure the nutritional requirements of cows producing 24 kg/d of milk (crude protein=14.4% DM; NDF=40.9% DM; milk FU=0.88/kg DM) and additional amounts of concentrates were distributed using automatic feeders. Four TMR samples were collected daily (7.00 am, 10.00 am, 1.00 pm, 4.00 pm) for six days during each experiment period for a total number of 48 feed samples. Each feed sample was subjected to the estimation of the particle size distribution using the separator of Pennsylvania State University composed of two sieves (diameters of 19 and 8 mm) and a collector on the bottom, and to the determination of the chemical composition. Changes of all three particle size fractions for TMRs were observed during the day with distributions of the TMR both once and twice daily. With the once daily distribution, the large particles fraction increased linearly (P

The aim of the present study was to compare in vitro methane (CH 4 ) production and other fermentation parameters from different substrates incubated either in rumen or faecal inoculum. Five different substrates were incubated in two different inocula and gas recordings were made using an automated in vitro gas production system. The substrates were: particulate matter obtained from reticulo-rumen (RR) digesta and faeces (FC) by wet sieving, timothy hay (H), first cut grass silage (S) and a mixture of grass silage and barley (50:50; SB). One gram of each substrate was incubated either in 60 ml buffered rumen or faecal inoculum taken from Swedish lactating dairy cows for 48 h. The results indicated that in vitro total gas production, predicted in vivo CH 4 production and the ratio of CH 4 production to total gas production were greater ( P in vivo CH 4 production was greater for substrates incubated in rumen inoculum (23.5 ml/g DM, 29.0 ml/g OM) as compared to faecal inoculum (11.2 ml/g DM, 14.3 ml/g OM). Predicted CH 4 production based on volatile fatty acids (VFA) stoichiometry equations (CH 4 VFA) showed no difference in CH 4 per mol VFA ( P =0.44) between the two sources of inoculum used for all substrates. Molar proportions of propionate were higher and that of butyrate were lower ( P P =0.13) in molar proportions of acetate was observed. Digestibility of neutral detergent fibre (aNDFomD) and true organic matter digestibility (TOMD) were lower ( P in vivo CH 4 production as compared to rumen inoculum. The discrepancy between observed and stoichiometric CH 4 production suggests an existence of acetogenesis in the hindgut.

This experiment aimed to investigate the associative effects among two low-quality forages (crown daisy, milk thistle) and three agro-industrial byproducts (apple pomace, citrus pulp, tomato peel), by means of an automated gas production (GP) system. All feeds were incubated alone or as 50 : 50 mixtures of each forage with each byproduct. Samples (0.500 ± 0.0010 g) of single feeds or mixtures were incubated for 96 h, in three replicates in individual bottles (310 mL), with 75 mL of buffered rumen fluid. Bottles were vented by an open-close valve when the internal pressure reached 3.4 kPa. The metabolisable energy content of single feeds and mixtures was computed from GP at 24 h and feed chemical composition. Feed substrates were ranked for GP in the following way: byproducts, mixtures, and forages. The two forages did not differ for GP and metabolisable energy content, although differences were observed among byproducts and among mixtures. Both forages interacted positively with apple pomace from 6 h (P < 0.001) to 24 h (P = 0.029) of incubation and with citrus pulp at 12 h (P = 0.005) and 24 h (P = 0.012), whereas no associative effects were detected when forages were incubated with tomato peels. Results suggest that in vitro fermentability of low-quality forages could be efficiently improved by combining these two forages with apple pomace or citrus pulp. These findings are relevant, because the use of low-quality forages and byproducts in ruminant feeding is considered important for improving the environmental and economic sustainability of forage systems in arid and semi-arid areas.

This study investigated growth performance, and carcass and raw ham quality of pigs from 4 genetic groups (GG), ANAS (A), DanBred (D), Goland (G) and Topig (T), fed conventional (CONV) or low-protein (LP) diets. In each of 3 trials, 96 pigs were housed in 8 pens in groups of 12 on the basis of their GG, sex (gilts and barrows), and BW. Each pen was assigned a CONV or LP diet. The CONV diets in early (89–120 kg BW) and late (121–165 kg BW) finishing contained 13.1 and 13.2 MJ/kg of ME, 147 and 132 g CP/kg, and 6.0 and 4.4 g/kg of standardized ileal digestible (SID) lysine, respectively. The LP diets in early and late finishing contained only 119 and 103 g/kg of CP, and 4.8 and 3.5 g/kg of SID lysine, respectively. Restricted feed allowance was increased on a weekly basis from 2.3 to 3.2 kg/d during the experiment. Automated feeding stations measured individual feed intake, and pigs were weighed at 3-weeks intervals until slaughter. Hot carcass was weighed and dissected into lean and fat primal cuts. After 24 h of chilling, hams were dressed, weighed, and scored for roundness (0 = low to 4 = high), fat cover thickness (−4 = thin to 4 = thick), marbling (0 = absent to 4 = evident), lean color (−4 = pale to 4 = dark), bicolor and veining (0 = absent to 4 = evident). In addition, ham backfat thickness was measured with a ruler. Dietary CP reduction did not influence final BW (166 kg), daily gain (0.67 kg/d), carcass weight (136 kg) or yield (0.82), but reduced feed efficiency by 5.2% (P subcutaneous fat depth), although increased marbling is expected. They should preferably be used with GGs that have low marbling scores under conventional conditions.

The effects of a shortage of dietary N and of a rumen protected CLA (rpCLA) supplement on DMI, rumination, rumen fluid characteristics, milk yield (MY), and milk N/N intake ratio (ENU) were studied in mid-late lactating cows. Twenty cows housed in 4 pens in groups of 5, homogeneous for parity, days in milk (DIM) and MY, were fed on 4 different diets: with 150 g (CP15) or 123 g (CP12) of CP/kg DM, with or without an rpCLA supplement (containing 6.34 g/d of C18:2c9,t11 and 6.14 g/d of C18:2t10,c12). A 4 × 4 Latin Square experimental design was used with periods of 3 wks, although the sequence of the 4 treatments (CP15 or CP12, with or without rpCLA) was such that each group received CP15 or CP12 for 6 consecutive wks. The CP12 diet was formulated from CP15 by replacing soybean meal with barley grain to maintain similar energy, fiber content and feed particle size. Rumination activity, DMI, and MY were recorded daily. Rumen fluid was analyzed for VFA and ammonia N content, and milk for quality traits. Nutrient digestibility was estimated using Lignin(sa) as a marker. Period, treatment and group (random) were included as sources of variation in the statistical analysis. Dietary CP restriction tended to reduce DMI (−7.7%; P = 0.09) and digestibility, but increased time spent in rumination (+10%; P = 0.009), decreased rumen fluid ammonia N (−36%; P

The evolution of the legislation concerning the environmental impact of livestock make necessary to find solution useful to evaluate and reduce the total excretion of nitrogen (N) and other possible pollutants at territorial and farm level. The methodological approach to evaluate the amount of nitrogen excreted proposed by ERM (1999) suggested that the amount of N excreted can be calculated as a difference between the amount of nitrogen consumed less the amount of N retained in the animal products.

This survey was aimed to evaluate the characteristics of dairy farms in the North- Eastern part of Po valley in terms of ration composition, milk yield and N and P excretions. Eightynine farms, with Italian Holstein Friesian cows, were selected in order to cover different situations in term of farm size and milk yield (MY). MY and quality were obtained from the national database of functional controls. Each farm was visited in order to collect information about ingredients and chemical composition of rations used. Farms were classified in four groups differing for dietary crude protein density (LCP15.3% DM) and for MY (LMY30 kg/d). N and P excretions were quantified by following a mass balance approach. Dietary crude protein content (CP) was not correlated to milk yield (MY) and quality. The estimated amounts of N excreted, discounted for 28% of N losses in atmosphere, were 78.5, 78.2, 87.2 and 89.1 kg/cow/year, and P excreted were 20.2, 18.6, 18.7 and 19.8 kg/cow/year for the LCPLMY, LCPHMY, HCPLMY, HCPHMY groups, respectively. On corn silage and cereals based rations, a dietary CP of 14.3% DM can support 31 kg MY/cow/day.

Effects of Butyl-Hydroxyl-Toluene (BHT) and of Red Chicory Extract (RCE) on kinetics of gas production (GP) and rumen degradability values (OMd, NDFd and in vitro true OM degradability - IVTOMD) of two feeds (meadow hay and corn meal) were evaluated using an in vitro automatic batch system. For each feed 2 increasing dosages (0.15 and 1.5 mg/g of feed) of BHT and RCE and a Control (C) were tested in 4 replications and 2 incubations. First incubation lasted 72h, the 2nd one was stopped at the times on which half of GP was produced (t½), which were 9 and 16 h for corn and hay, respectively. From the supernatants of the 2nd incubation, VFA, NH3, N content of the residual NDF were analysed and the microbial N balance was computed. The 2 feeds significantly affected rumen fermentation parameters; BHT significantly increased asymptotic GP, t½ and IVTOMD (P

This study compared measured gas production (GP) and computed CH4 production values provided by closed or vented bottles connected to gas collection bags. Two forages and 3 concentrates were incubated. Two incubations were conducted, where the 5 feeds were tested in 3 replicates in closed or vented bottles, plus 4 blanks, for a total of 64 bottles. Half of the bottles were not vented, and the others were vented at a fixed pressure (6.8 kPa) and gas was collected into one gas collection bag connected to each bottle. Each bottle (317 mL) was filled with 0.4000 ± 0.0010 g of feed sample and 60 mL of buffered rumen fluid (headspace volume = 257 mL) and incubated at 39.0°C for 24 h. At 24 h, gas samples were collected from the headspace of closed bottles or from headspace and bags of vented bottles and analyzed for CH4 concentration. Volumes of GP at 24 h were corrected for the gas dissolved in the fermentation fluid, according to Henry's law of gas solubility. Methane concentration (mL/100mL of GP) was measured and CH4 production (mL/g of incubated DM) was computed using corrected or uncorrected GP values. Data were analyzed for the effect of venting technique (T), feed (F), interaction between venting technique and feed (T × F), and incubation run as a random factor. Closed bottles provided lower uncorrected GP (-18%) compared with vented bottles, especially for concentrates. Correction for dissolved gas reduced but did not remove differences between techniques, and closed bottles (+25 mL of gas/g of incubated DM) had a greater magnitude of variation than did vented bottles (+1 mL of gas/g of incubated DM). Feeds differed in uncorrected and corrected GP, but the ranking was the same for the 2 techniques. The T × F interaction influenced uncorrected GP values, but this effect disappeared after correction. Closed bottles provided uncorrected CH4 concentrations 23% greater than that of vented bottles. Correction reduced but did not remove this difference. Methane concentration was influenced by feed but not by the T × F interaction. Corrected CH4 production was influenced by feed, but not by venting technique or the T × F interaction. Closed bottles provide good measurements of CH4 production but not of GP. Venting of bottles at low pressure permits a reliable evaluation of total GP and CH4 production.

Guadagnin, M., Tagliapietra, F., Cattani, M., Schiavon, S., Worgan, H. J., Belanche, A., Newbold, C. J. and Bailoni, L. 2013. Rumen fermentation and microbial yield of high- or low-protein diets containing ground soybean seeds or homemade rapeseed expellers evaluated with RUSITEC. Can. J. Anim. Sci. 93: 363–371. This experiment aimed to compare diets containing two crude protein (CP) concentrations [147 or 109 g kg−1in dry matter (DM)] and two protein sources containing ground soybean seed (GSS) or rapeseed expeller (RSE). Diets were compared in terms of digestibility, volatile fatty acids (VFA) and ammonia concentrations, and N flows, using rumen simulation fermenters (RUSITEC). Home−made RSE (CP=287 g kg−1dry matter and ether extract=199 g kg−1DM) was produced using equipment adopted by small farms. Reduction of dietary CP content did not affect digestibility, except for a reduction of N apparent digestibility (P

This trial compared the effects of two antioxidant phenols, butyl-hydroxyl-toluene (BHT) and a blend of polyphenols extracted from red chicory, on in vitro degradability, gas production (GP), volatile fatty acids, and microbial nitrogen production, using meadow hay and corn grain as fermentation substrates. A batch culture system with automated gas pressure detectors was used. Four replicates of each feed were incubated for 72 h without additive (Control, CTL) or with the addition of low (0.15 mg/g feed) or high (1.5 mg/g feed) dosages of BHT or red chicory. GP curves were fitted to estimate the time at which half of total GP (t1/2) was achieved. The t1/2 values for meadow hay and corn grain were ~16 and 9 h, respectively. A second incubation, conducted using the same experimental design, was stopped at t1/2. Compared with CTL, degradability and GP kinetics were not affected by the two dosages of BHT, except for GP, which increased after 48 h of incubation (P < 0.01). In the second incubation, BHT increased acetate at the expense of butyrate proportion (P < 0.01). Red chicory extract did not influence GP, feed degradability, or volatile fatty acids production in either incubation. Both BHT and red chicory induced a dosage-dependent increase in microbial nitrogen production at t1/2 (P < 0.05), on average from 7.0 to 13.9 mg/g DM. Collectively, our data suggest that increasing dosages of the two additives with antioxidant properties could have induced a shift in the partition of energy, with a higher proportion of nutrients channelled towards microbial protein synthesis.

A trial was carried out on double-muscled Piemontese bulls to evaluate the effects of two rations differing in crude protein density (HP = 14.5% DM and LP = 10.8% DM) and top dressed or not with 80 g/d of rumen protected CLA (rpCLA) for a long period (336 d) on meat quality traits and CLA content. Forty-eight bulls were fed one of the four experimental diets based on corn silage and cereals and were slaughtered at an average age and body weight (BW) of 562 ± 18 d and 668 ± 56 kg, respectively. After slaughter the 5th rib cut was dissected into Longissimus thoracis (LT), other muscles (OM), inter-muscular fat (IF), cover fat (CF), and bones. Muscles and fatty tissues were analyzed for proximate composition and fatty acid (FA) profiles. Rib was composed by 81.1, 3.7, 1.6 and 13.6% of muscles, IF, FC and bone, respectively; LT and OM contained only 0.8 and 1.4% of lipid, respectively. The treatments did not influence these values, but rpCLA increased, compared to control, both c 9, t 11-CLA and t 10, c 12-CLA concentrations in all the tissues ( P t 10, c 12-CLA concentration was increased much more in muscles (+ 20 times) than in fatty tissues (from + 0.2 to + 0.9 times). This suggests that in the muscle this isomer is preferentially stored and/or less combusted with respect to other fatty acids. Low protein rations did not exert any influence on carcass and meat quality, as on growth performance, but reduced nitrogen excretion, their use for improving the environmental impact (process quality) of this meat production system is recommended.

A simplified approach to predict the amount of slurry produced by growing pigs at farm level is proposed. The inputs are initial (LWi) and final (LWf) live weights, production (t) and empty (empty) periods, feed consumption (FC), dry matter (DMD), N digestibilities and farm water consumption per pig (FWC). Estimates of the amount of water required (or arisen) per kg of feed for the various physiological functions were estimated by running a published mathematical model using data representing the ordinary conditions of rearing. Water excretion was estimated in two ways depending on: 1) free access (ad lib) to water; 2) restricted access (forced). In the first case, the proportion of water consumed (wiad lib) and those excreted with the urine (wuad lib) and the faeces (wfec) were quantified to be 2.9, 1.72 and 0.33 kg per kg of feed, respectively. From the urinary excretions of N and minerals, obtained as the difference between the digestible nutrient intakes and the retentions, the model predicted a urinary DM content of 2.1% (by weight). In the second case, for pigs receiving drinking water in forced ratio with the feed (wiforced), the urinary production was calculated as wuforced=(wiforced+wf+wo)-(wd+ws+wg+wfec+we), where wf=water content in feed (0.12 kg/kg), wo=water arising from nutrient oxidation (0.25 kg/kg), wd=water required for digestion (0.08 kg/kg), ws=water demand for protein and lipid synthesis (0.06 kg/kg), wg=water retained in body tissues (0.14 kg/kg) and we=water lost through evaporation (0.96 kg/kg). Estimates of fresh slurry production (faeces+urine) were regressed against the values resulting from empirical literature equations and referred to pigs fed water:feed ratios of 2.5:1, 2.9:1 and 4:1. The resulting regression (R2=0.97), with a slope close to unity (1.05), indicated that the approach can be extended to predict the farm fresh slurry production with pigs having free access to water or kept on different water:feed ratios. In agreement with international literature, but not with the current Italian national standards, estimates of mature slurry productions ranged from 1.5 to 2.9 ton/pig/year with DM contents ranging from 8.3 to 3.7%. At farm level the use water meters is recommended as from FWC minus the estimated water consumption (FWCexp) the farmer can evaluate the extra wastage and adjust the predicted mature slurry production.

Growth performance and N excretion of double muscled Piemontese (DMP) bulls were investigated. Forty-eight DMP bulls (LW 279 kg), divided in 4 groups, housed in 12 pens, were fed 2 rations (TMR) differing for crude protein density (diets HP: CP=14.7% DM; diets LP: CP=11.0% DM) and top dressed with 80 g/d of rumen protected CLA (CLA) or with 65 g/d of hydrogenated soybean oil (HSO). DM intake was measured, weekly and on pen basis, from the weights of feed distributed and orts. Bulls were weighted monthly. Trial lasted 334 d. Data were analysed by ANOVA. Over the whole trial, no effects due to CP, to additive (A) or to CPxA were found on final LW (670 kg), average daily gain (1.187 kg/d), DM intake (8.50 kg/d), and on SEUROP (5.2 points) and cold dressing (67.3%). Interaction CPxA affected (P

Nel lavoro si propone una procedura per stimare le variazioni di composizione chimica corporea e dell’in gestione alimentare di suini, allevati in condizioni non limitanti, basata su rilievi di peso vivo (BW) e di spessore del grasso dorsale (P2) ripetuti a diverse età. Si è utilizzata una banca dati riguardante 920 suini ibridi maschi (Goland) alimentati ad libitum che ha fornito informazioni individuali di BW, misurato a 71 ± 4 (t1), 126 ± 5 (t2) and 184 ± 5 (t3) giorni di età, di P2, misurato alle età t2 e t3, e di ingestioni ali mentari (FI), registrate nell’intervallo di tempo tra t2 e t3 mediante stazioni di alimentazione automatiz zate (IVOG). La massa corporea di lipidi (kg) è stata stimata con l’equazione L= (9,17 + 0,70*P2)*BW/100 e gli altri costituenti corporei sono stati calcolati dal peso vivo netto meno la frazione lipidica, utilizzando funzioni di allometria. Dai cambiamenti stimati di composizione corporea tra le età t2 e t3 sono stati quindi valutati i fabbisogni di energia per il mantenimento e per la crescita ottenendo i cor rispondenti quantitativi di mangime previsti per il periodo di crescita in esame (PFI) per ciascun indivi duo. I valori misurati di consumo alimentare (FI) ottenuti dalle stazioni IVOG sono stati sottoposti ad ana lisi della varianza per gli effetti: mese, partita (entro mese), BWt2, P2t2, accrescimento medio giornaliero e variazioni di P2 nel periodo tra t2 e t3. I valori di FI sono stati anche analizzati sostituendo, come fonti di variazione, le misure corporee dirette con stime derivate di PFI. Risultati. L’approccio seguito ha con sentito di stimare i parametri delle curve di Gompertz che definiscono la crescita proteica potenziale di ciascun individuo, la massa proteica matura (Pm, kg), il coefficiente di accrescimento relativo (B, d-1) e il rapporto lipidi:proteine a maturità (Lm/Pm), risultati in media pari a 43,5 ± 5,8 kg, 0,0116 ± 0,0011 d-1 e 1,81 ± 0,30, rispettivamente. Nel periodo compreso tra t2 e t3 la massa proteica mediamente pre sente è risultata pari a 18,5 + 1,6 kg e le ritenzioni medie di proteine e lipidi sono state in media pari a 177 ± 21 e 239 ± 62 g/d, rispettivamente. I valori medi di FI e di PFI sono stati, rispettivamente, pari a 2,824 ± 0,448 and 2,814 ± 0,393 kg/d. Nel modello di analisi statistica la sostituzione delle misure cor poree dirette con i valori di PFI non ha modificato la proporzione di varianza spiegata (83%) né i valori di deviazione standard residua (0,199 g/d). I valori di “residual feed intake” risultanti dall’applicazione dei due modelli di analisi sono risultati altamente correlati (RSD= 0,043 kg/d; R2= 0.961). L’approccio impiegato ha quindi consentito di ottenere una buona interpretazione biologica della varianza dei valori di FI associata alle diverse misure corporee. La sostanziale coincidenza tra valori misurati e stimati di ingestione alimentare ha fornito una ragionevole garanzia sulla validità dei valori di composizione corpo rea stimati. Così, un protocollo di misure ripetute di peso vivo e di spessore del lardo dorsale nel corso della crescita, accoppiato ad elaborazioni di tipo allometrico, può essere proposto per stimare in vivo lo stato chimico corporeo di suini allevati in condizioni ritenute non limitanti. The paper provides a practical procedure to estimate the chemical composition of pigs, their compositional growth and the expected feed intake from measurements of body weight (BW) and backfat thickness (P2) serially performed in vivo. A farm data set provided information on 920 individuals including BW, measured at 71 ± 4 (t1), 126 ± 5 (t2) and 184 ± 5 (t3) days of age, of P2 at t2 and t3, and of voluntary daily feed intake (FI), recorded over the period from t2 to t3 by automated IVOG feeders. Body lipid mass was estimated as L= (9.17 + 0.70*P2) *BW/100 and the other chemical constituents were predicted from fat free empty body mass using Gompertz growth functions and allometry. Using individual changes of body composition from age t2 to t3, energy requirements for maintenance and growth and the corresponding predicted feed intakes (PFI) were estimated. Measured FI were analysed for the effects of month, batch (within month), BWt2, P2t2, average metabolic weight, average daily gain and variation of P2 from t2 to t3. The same model was run again replacing the direct simple body measurements (BW and P2) with the estimated values of PFI as source of variation. Results. The Gompertz estimates of mature protein mass (Pm), relative growth rate parameter (B) and lipid to protein ratio at maturity were 43.5 ± 5.8 kg, 0.0116 ± 0.0011 d-1 and 1.81 ± 0.30, respectively. The current protein mass averaged 18.5 + 1.6 kg and the daily retentions of protein and lipid were 177 ± 21 and 239 ± 62 g/d, respectively. FI and PFI averaged 2.824 ± 0.448 and 2.814 ± 0.393 kg/d, respectively. In the ANOVA of the FI data, the replacement of direct body measurements by PFI did not change the proportion of variance explained (83%) and the RSD (0.199 g/d). The two sets of residual feed intake values obtained from the two ANOVA were highly correlated (RSD = 0.043 kg/d; R2= 0.961). Agreement between predicted and determined feed intakes provided a reasonable guarantee to the estimated (based on BW and P2) changes of body composition. Thus, a scheduled protocol of measurement of BW and P2 over the course of growth, coupled with the use of allometry, can be proposed to estimate in vivo the change of the chemical status of pigs kept under non limiting conditions.

The effects on milk yield and quality caused by the same amount (325 g/d/cow) of lipids provided by 3 different fat sources (hydrogenate palm fat, HF; calcium salt palm fat, CaSF; full-fat toasted soybean, TS), top dressed to a common total mixed ration, were investigated. Supplementations did not affect feed intake and milk yield, but markedly changed the acidic profile of milk fat. CaSF and TS significantly increased the proportions of unsaturated fatty acids of milk fat with respect to control and to HF. The 3 fat sources did not affect the concentrations of ammonia and VFA of rumen fluid. TS only slightly increased (P

Pectic substances, found in the primary cell wall and middle lamella of the plant tissues as complex polymers of galacturonic acid, play an important nutritional role in the gastrointestinal tract. Their dietary function is due to their physical properties, which include the ability to form gels, to build cations and to increase the waterholding capacity (Voragen et al., 1995, 2001). These physical characteristics are dependent on the substances’ chemical structure and, consequently, pectic substances are fractionated into HM pectins (high-methoxyl pectins), LM pectins ( low-methoxyl pectins) and protopectin (Thibault and Ralet, 2001). Must studies have been carried out on fruit because the ripening process induces a modification of the amount of total pectins (TP) and also of the ratio among the three fractions (Robertson, 1979). Moreover, the additives employed in the food industry are usually obtained from apple or citrus extraction (Thibault and Ralet, 2001). The purpose of this preliminary work is evaluation of the fractional extraction procedure and quantitative determination of total pectic substances of different feeds.

The dietary fibre of 24 foods was analysed for its proportions of insoluble and soluble (SDF) fractions and for its contentof high methoxyl pectins (HM), low methoxyl pectins (LM) and protopectin. The fractional extraction and quantitativedetermination of pectins were performed on the total dietary fibre residue, following the procedure suggested byRobertson (1979). Total pectin content (TP), calculated as sum of the three fractions, ranged from 2.4 to 49.8 g/kg ofdry matter. The variation coefficient of TP measurements repeated on the same foods were, on average, 2%. Total pectincontent was 49.8 g/kg DM in dried beet pulp and averaged 33.8+_0.3 g/kg DM in fruits and vegetables, 13.2+_8.4 g/kgDM in legumes and tubers and only 2.8+_0.5 g/kg DM in cereals. HM fraction prevailed in apple and pear samples (>40%of TP), while LM and protopectin largely prevailed in legumes and vegetables. A strong variability among foods was foundfor the TP/SDF ratio. In general, within each food category, increasing levels of SDF were associated with decreasing valuesof TP/SDF ratio. Since many foods contain low amounts of pectins, care in the development of calibration curves forspectrophotometric reading is required. Finally, the whole procedure for pectin extraction and quantification on dietaryfibre of food is very complex and time-consuming.

The fermentation properties of the following feeds: pelleted barley (PB), toasted and pelleted barley (TPB), pelleted maize (PM) and toasted and pelleted maize (TPM) were studied using an in vitro gas production (GP) technique. Each feed sample (0.5g) was incubated (3 replications), with rumen fluid collected from 3 grazing lactating dairy cows. The kinetics of GP were automatically recorded for 72h. The amounts of DM disappeared (DMd) and the volatile fatty acid yields (VFA) were measured. On barley, compared to simple pelleting, toasting significantly (P

Background Modification of chemical composition of diets fed to dairy cows might be a good strategy to reduce methane (CH4) production in the rumen. Notable reductions of CH4 production compared to conventional high-roughages rations were more frequently observed for very concentrated diets or when fat supplements were used. In these cases, the reduction in the gas emission was mainly a consequence of an overall impairment of rumen function with a reduction of fiber digestibility. These strategies do not always comply with feeding standards used in intensive dairy farms and they are usually not applied owing to the risks of negative health and economic consequences. Thus, the present study evaluated the effects of seven commercial diets with contents of neutral detergent fiber (NDF), protein and lipids ranging 325 to 435 g/kg DM, 115 to 194 g/kg DM, and 26 to 61 g/kg DM, respectively, on in vitro degradability, gas (GP), and CH4 production. Results In this experiment, changes in the dietary content of NDF, crude protein (CP) and lipids were always obtained at the expense or in favor of starch. A decreased of the dietary NDF content increased NDF (NDFd) and true DM (TDMd) degradability, and increased CH4 production per g of incubated DM (P