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Emerging issues in animal husbandry: effects of reduced protein supply in animal farms and methodologies for fatty acid analysis in biological samples
Full text linkAim of this thesis was to explore the effects of suboptimal N supplies on animals of different species on production performances to achieve an effective reduction of N excretion avoiding, or limiting, the economic losses due to impairment of performance or reduced quality of products. As aside different methods of fatty acid analysis were evaluated to identify an accurate and repeatable methodology of extraction of fatty acids that prevents isomerisation of PUFA and conjugated linoleic acid. All the contributions of this thesis have been published or submitted to international peer reviewed journals. This thesis was also reviewed by foreign referees and all their suggestions were accepted and included in the present version of this thesis. The first two contributions were aimed to verify the effect of suboptimal dietary crude protein supply on growing cattle and lactating cows. In lactating cows the effect of a supplementation with rumen protected conjugated linoleic acid (CLA) was also explored. The third contribute regards an experiment conducted to evaluate the effect of different fecal sample preparation procedures to determine the fatty acid profile of ruminants feces, including CLA. The fourth and the fifth contributions were aimed to evaluate the effects of reduced dietary crude protein and amino acid levels on growth performance of heavy pigs (4th contribute) and on growth performance and intramuscular lipid deposition on fast growing pigs (5th contribute). Overall, the results suggests that considerable reduction of dietary crude protein, compared to conventional standard, can be applied with small or null impairment of production response, but with a notable reduction of N excretion. Within the framework of the nitrate directive of the European Community, the strong reduction of N excretion achieved with the use of suboptimal protein supplies would result in the possibility of increasing the number of animals reared per unit of land available for manure disposal, and to reduce the feeding costs because of less use of expensive dietary protein sources. From the third contribute it resulted that fecal sample preparation method has an influence on fecal fatty acid profile, and in particular on the CLA component, stronger than that was previously evidenced in the literature that indicated the methylation as a critical step for an accurate analysis of fatty acids by gas chromatography. Analytical methods applicable on different biological substrates (feeds, feces, and animal products) are needed for a better knowledge of lipid digestion and metabolism of farm animals
Influence of dietary CP and rumen protected conjugated linoleic acid on rumination activity, feed intake and rumen fluid parameters in lactating cows
No full textEFFECT OF PROTEIN SHORTAGE AND CONJUGATED LINOLEIC ACID SUPPLEMENTATION ON QUALITY TRAITS AND MODELLING OF COAGULATION, CURD FIRMING AND SYNERESIS OF HOLSTEIN-FRESIAN MILK
Full text linkAim of the present study was to evaluate the effect of diets with optimal (CP 15% DM) or suboptimal (CP 12.3% DM) protein content, supplemented (CLA+) or not (CLA-) with rumen-protected conjugated linoleic acid (rpCLA) on some cheesemaking properties. Twenty Holstein-Fresian mid lactating dairy cows have been reared following a 4×4 Latin square experimental design of 4 periods, 3 weeks each. Individual milk samples, collected during the third week of each period, were analysed for chemical composition, traditional milk coagulation properties (MCP: RCT, k20 and a30) and for recording curd firmness (CF) every 15 s over a 90 min period. Data acquired from each sample were used to model CF over time calculating the following parameters: rennet coagulation time (RCTeq), asymptotic potential CF (CFP), CF rate constant (kCF), syneresis rate constant (kCF), maximum CF achieved within 90 min (CFmax) and time to CFmax (tmax). Data were analysed using period, diet and group (random) as sources of variation. Cows evidenced a strong individual variability within groups and were classified as early (RCT20 min) coagulating cows. Dietary protein shortage reduced milk protein and lactose content, while rpCLA supplementation depressed milk fat synthesis. Results showned that traditional MCP parameters were worsened by reduction of dietary protein in the case of milk produced by early coagulating cows, while rpCLA supplementation affected negatively all three traits on all cows. The study of CF model parameters evidenced that CP12 diets have improved CF (CFP and CFmax) respect to CP15 when fed to late coagulating cows while worsened CF (CFP and CFmax) and reduced kCF when fed to early coagulating cows. The results of the present study underline the complex relationship between dietary fat and protein and their consequences on milk technological properties highlighting the need for further investigations
Environmental footprint of a France – Italy integrated beef production system with a LCA approach
No full textThe beef production in Italy is conglomerated in the Po Valley, and is based on young bulls imported
mainly from France and intensively fattened using total mixed rations (TMR) based on maize silage and
concentrates. This study aimed to examine the environmental footprint of intensive beef sector of Veneto
region through a cradle-to-farm-gate life cycle assessment (LCA). The batch (a group of animals homogenous
for breed, diet, fattening period, and finishing herd) and 1 kg of Body Weight (BW) were taken as system
boundary and functional unit respectively. The considered impact categories were greenhouse gases (GHG)
emission (kg CO
2
-eq) and eutrophication (g PO
4
-eq). The study involved 198 batches (Charolaise breed)
and 15 specialized beef fatteners. An on farm survey was conducted for the fattening period in Italy (225±17
d, from 392±25 to 734±21 kg BW), whereas the French cow-calf phase emissions were obtained from
literature data. On-farm data for crop-to-feed production and materials (fuel, electricity, plastic, lubricant,
fertilisers) were recorded during 2013; off-farm emissions were based on literature and software data
(Simapro 7.3.3 – Ecoinvent database v.3.0). Mean GHG emission was 14.3±0.8 kg CO
2
eq/kg BW, while
eutrophication was 59±6 g PO
4
-eq/kg BW. The Italian fattening phase contributed for 27% and 35% on
average to GHG emissions and eutrophication respectively. For the intensive fattening period, the factors
affecting the environmental footprint were average daily gain (1.53±0.09 kg/d) and diet composition. The
cow-calf phase will be further investigated in order to analyse the variability of impact categories and the
ecosystems services provided by animal grazing, with the perspective to obtain a holistic evaluation of the
sustainability of the integrated France – Italy beef production system
Factors affecting performance and economic traits of intensively managed beef cattle in Italy
No full textIn Italy nearly two thirds of the beef bulls are reared in northern regions by specialized intensive fatteners that import stock calves from other European countries, mainly from France. Usually they feed them until slaughter with total mixed rations based on maize silage and concentrates. The increase of feed and animal purchase costs, the growing requirements for environmental sustainability and the expected detrimental changes in Common Agricultural Policy for intensive systems are currently endangering the viability of this sector. This study aimed to analyse the effects of management factors such as beef breed, body weight (BW) at arrival and diets on performance traits, nutrient excretion and net sale gain (NSG), taken as economic indicator, computed as (beef value at sale – beef value at purchase) and expressed per day of fattening (€/d). Seventeen specialized fattening herds were visited monthly during 1 year to collect performance data and diets formulation and composition. The data were analyzed using ANOVA with herd, breed and classes of management factors as fixed effects. The fattening period for beef cattle lasted on average 229 d, with an average BW at purchase and at sale of 370 and 671 kg, respectively. The average NSG computed per day of fattening was 2.44 €/d, with a large variation due to herd and breed. Feed intake averaged 9.75 kg DM, and the average gain to feed ratio was 7.5. Diets were characterised by an average crude protein and phosphorus content of 141 g/kg DM and 3.78 g/kg DM, respectively, the ratio between NSC and NDF averaged 1.4, and average self-sufficiency was 33% on daily DM intake. During the production cycle the intake, the retention and excretion of nitrogen averaged 0.22, 0.04 and 0.18 kg/d, respectively, and those of phosphorous averaged 0.04, 0.01 and 0.03 kg/d, respectively. Further studies are needed for better defining the profitability of this system by including the ratio and cost of feedstuffs purchased outside the farm
Influence of N shortage and conjugated linoleic acid supplementation on some productive, digestive, and metabolic parameters of lactating cows
No full texttThe effects of a shortage of dietary N and of a rumen protected CLA (rpCLA) supplementon 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 of5, homogeneous for parity, days in milk (DIM) and MY, were fed on 4 different diets: with150 g (CP15) or 123 g (CP12) of CP/kg DM, with or without an rpCLA supplement (containing6.34 g/d of C18:2c9,t11 and 6.14 g/d of C18:2t10,c12). A 4 × 4 Latin Square experimentaldesign was used with periods of 3 wks, although the sequence of the 4 treatments (CP15or CP12, with or without rpCLA) was such that each group received CP15 or CP12 for 6consecutive wks. The CP12 diet was formulated from CP15 by replacing soybean meal withbarley grain to maintain similar energy, fiber content and feed particle size. Ruminationactivity, DMI, and MY were recorded daily. Rumen fluid was analyzed for VFA and ammoniaN 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 variationin the statistical analysis. Dietary CP restriction tended to reduce DMI (−7.7%; P = 0.09) anddigestibility, but increased time spent in rumination (+10%; P = 0.009), decreased rumenfluid ammonia N (−36%; P < 0.001), and reduced MY (−4.8%; P = 0.047) and milk proteincontent (−4.7%, P = 0.026); it had no influence on the ratio between energy-corrected milkyield and DMI. CP restriction reduced N intake by 122 g/d and N in milk by 14 g/d, didnot influence N in feces, but increased ENU from 0.31 to 0.36 (P < 0.01). A low marginalresponse of 115 g milk N/kg to the increased N intake from soybean meal was found. Theaddition of rpCLA tended to reduce DMI (−8.1%; P = 0.07) and decreased milk fat content(−15%; P = 0.002), but decreased N in milk only when added to CP12 (CP × rpCLA interaction,P = 0.016). A shortage of N supply increases ENU without apparent alteration of BW, BCSand blood metabolites. Long-term investigations to clarify the role of body N reserves andof a shortage of CP supplies on N partitioning are needed
Sustainability of intensive beef production system in North-East Italy: relationships between phosphorus supply and productive performance
No full textThe beef sector of the Veneto Region is based on young bulls imported mainly from France and reared intensively using total mixed rations based on maize silage and concentrates. While nitrogen excretion of the sector is regulated by Nitrate Directive, the excretion of phosphorus (P) is less studied, despite of its potentially great impact on environment. This study aims at analysing the relationships between productive and economic performances and P content of the diet in 14 farms of the region. For a whole productive year feed consumption, ingredients and chemical composition of diets were monthly collected. Average Daily Gain (ADG), Feed conversion ratio (FCR), daily gross profit (DGP), and P balance were calculated. ADG, FCR, and DGP were analysed with a mixed model using arrival season, arrival weight, class of dietary content of P, protein and starch as fixed effects and farm as random effect. Average daily gain was 1.39±0.08 kg/d, FCR was 0.14±0.01 kg/kg, and DGP 2.5±0.40 €/d. The P dietary content was on average high (0.38±0.04, % DM), which resulted in P intakes and excretions of 13.49±1.94 and 9.85±1.92 kg/head/place, respectively. None of the productive and economic traits was affected by phosphorus content of the diet. As a consequence, the phosphorus supplementation can be reduced without the risk of weakening productive and economic performances
Alteration of bovine milk fatty acid profile caused by the dietary crude protein content supplemented or not with rumen protected conjugated linoleic acids
No full textTwenty cows housed in 4 pens, homogeneous for parity, days in milk (DIM), and milk yield (MY) received 4 diets with 150 (CP15) or 123 (CP12) g of CP/kg DM, supplemented or not with rumen protected conjugated linoleic acids (rpCLA) (6.34 and 6.14 g/d of C18:2c9,t11 and C18:2t10,c12, respectively), according to a 4x4 Latin Square design. Dry matter intake and milk yield were recorded daily and milk samples were collected during the last of 3 wks of each of the 4 experimental periods. Milk fatty acids (FA) were extracted with hexane-isopropanol and methylated with sodium methoxide. Commercial standards for FA molecules were used to identify milk FA and their detection was performed using a bi-dimensional gas chromatographer. Data were analyzed with a mixed model which considered period, dietary treatment as sources of variation and group as residual error term. The dietary CP had small influence on the FA profile, as only few FA, mainly some odd and branched FA, were altered. In particular, cows receiving the low protein diet produced milk with a significantly greater proportion of branched and odd FA (P<0.001) compared to control. Differently, rpCLA had a strong influence on the FA profile, as it reduced the proportion of short and medium chain FA and that of saturated FA (P<0.001) and increased the proportion of CLA (P<0.001)
A Comparison among Analytical Methods to Assess Fatty Acids and Conjugated Linoleic Acids (CLA) Content and Repeatability of Ruminant Faeces
Full text linkMethods to determine fatty acids (FAs) and CLA contents of faeces should limit isomerisation, provide a good repeatability of the measures, avoid the use of harmful substances. Three methods of FAs extraction from faeces for GC analysis were compared: Est-DFtol, based on extraction and esterification of FAs contained in dry faeces using Na-methoxide, methanolic-HCl and toluene as solvent; Est-EEtol, based on acid-base extraction and esterification of FAs on the faecal ether extract (EE), using toluene as solvent; and AEst-EEhept, based on an acid catalyzed esterification of FAs contained in EE, using n-heptane as solvent. Faeces were collected from bulls receiving 0, 8 and 80 g/d of rumen protected CLA (rpCLA). The faeces of 9 bulls (3 for each dose) were analysed in triplicates by each method. Methods were compared by linear regression. The measurements performed with Est-EEtol and AEst-EEhept regressed against those of Est-DFtol, evidenced, in particularly for CLA isomers and their sum, positive intercepts and slopes significantly lower than the unity. The proportions of c18:2,t9,t11 found with Est-DFtol and AEst-EEhept were correlated to the dose of rpCLA (R = 0.87 and 0.51, respectively), whereas those found with Est-EEtol did not (R = 0.17). The Est- DFtol method is recommended because it minimizes the isomerisation of the polyunsaturated fatty acids and yields a more accurate measurement of the FAs profile
Sources of variation of the environmental impact of cereal-based intensive beef finishing herds
No full textThis study aimed to investigate the effect of beef category, feedstuffs self-sufficiency (SELF), crude protein (CPI) and phosphorus (PI) daily intake on the environmental impact of the beef fattening system typical of north-eastern Italy according to a partial Life Cycle Assessment. The reference unit was the batch (group of animals homogeneous for genotype, sex, fattening farm, finishing period). The study involved 245 batches (64 ± 34 heads) herded in 17 fattening farms. The system boundaries were set from animals arrival at the fattening farm to the sale to the slaughterhouse. The functional unit was 1 kg BW gain (BWG). Data on animal performance and farm input were collected for each batch and farm, respectively. Data on feed intake, ingredient formulation and chemical composition of diets were monthly collected for each batch. Impact categories assessed were (mean ± SD per kg BWG in brackets): global warming (8.8 ± 1.6 kg CO2-eq), acidification (142 ± 22 g SO2-eq) and eutrophication (55 ± 8 g PO4-eq) potentials, cumulative energy demand (53 ± 18 MJ), land occupation (7.9 ± 1.2 m2/year). Beef category and SELF, CPI and PI classes significantly affected all the impact categories, with lower values observed with decreasing values of CPI and PI and increasing values of SELF as well as more productive beef categories. This study evidences that beef category and diet-related factors affect the environmental impact of cereal-based intensive beef finishing herds. In conclusion, there is space to develop mitigation strategies based on enhancing the self-sufficiency rate of the diet and lowering the daily intake of crude protein and phosphorus
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