Lucia Bailoni

Nitrogen excretion in dairy cow, beef and veal cattle, pig, and rabbit farms in Northern Italy

Abstract Reference values for N excretion of different livestock production systems are required for the application of the Nitrate Directive (91/676/EC). A survey aimed to estimate N excretion from on-farm measurements of feed consumption and performance of dairy cows (104 herds, 9,984 cows), growing cattle (40 farms, 40,157 young bulls), veal calves (34 farms, 49,206 calves), growing pigs (39 farms, 161,278 pigs) and rabbits (54 farms, 65,664 reproducing does) was conducted in Veneto from 2002 to 2003. N excretion was computed as the difference between N consumption and N retained in animal products. Dairy cow yielded 8,366 ± 1,646 kg/year of milk, consumed 6,600 ± 928 kg/year of DM, containing 2.45 ± 0.2 % DM of N, and excreted 116 ± 25 kg of N/year. No significant correlation was found between milk yield and N excretion, but the correlation between dietary N concentration and N excretion was significant (r=0.66). For growing cattle, the following mean values were achieved: daily gain 1.25 ± 0.19 kg/d; feed conversion ratio 6.9 ± 0.9 kg of DM/kg, rounds/year 1.66 ± 0.38. Nitrogen consumed, retained and excreted were, respectively, 68.7 ± 5.4, 11.4 ± 1.9 and 57.3 ± 4.9 kg/place/year. For veal calves, N consumed was 24.1 ± 1.9 kg/place/year, 12.1 ± 0.8 kg of which were retained in the body and 12.0 ± 1.5 kg were excreted. For heavy pig production, N consumed, per place and per year, averaged 19.0 ± 1.9 kg, N retained was 5.2 ± 0.5 kg and N excreted was 13.8 ± 0.4 kg. In the close-cycle rabbit farms, the doe and the relative growing rabbits (43 sold per year) consumed 11.2 ± 2.2 kg, retained 3.8 ± 0.7 kg and excreted 7.4 ± 1.5 kg N/doe/year. Nitrogen excretion estimated in this work can be considered as representative of some of the main animal production systems of the North-East of Italy. These values should not be considered as fixed, otherwise the implementation of the various strategies to reduce N excretion would not be possible. They should be considered as guidelines in the assistance both to public institutions and private enterprises in the evaluation of N excretion at farm level, favouring a more accurate quantification of the excretions, an increase of N retention efficiency and a better knowledge of the requirements of agricultural land. Moreover, a major extension of the agricultural land to be fertilised with manure should be promoted.

Effects of low-protein diets and rumen-protected conjugated linoleic acid on production and carcass traits of growing double-muscled Piemontese bulls.

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, because 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 carcass traits.

Effect of high or low protein ration combined or not with rumen protected conjugated linoleic acid (CLA) on meat CLA content and quality traits of double-muscled Piemontese bulls.

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 c9,t11-CLA and t10,c12-CLA concentrations in all the tissues (P<0.01); t10,c12-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.

Effects of yeast culture addition on digestion in sheep fed a high concentrate diet

Abstract Effects of yeast culture on intake, rumen parameters, digestibility and passage rate were studied in 12 sheep (average BW 59±3.5 kg). A high concentrate diet was supplemented with 0 (control), 20 (Y20) or 40 (Y40) g/d of yeast. DMI tended to be higher (P

Technical note: In vitro total gas and methane production measurements from closed or vented rumen batch culture systems

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 Henrys 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.

Effect of proteinate or sulphate mineral sources on trace elements in blood and liver of piglets

Four hundred piglets were housed in 20 pens and offered for 42 days a pre-starter and then a starter compound supplemented with trace elements given as sulphates (SULF) or proteinates (PROT) at a common level (100) or at a reduced level (20) of inclusion. The common level supplied 278, 148, 315 and 98 mg/kg and the reduced level supplied 128, 38, 135 and 50 mg/kg of iron (Fe), copper (Cu), zinc (Zn) and manganese (Mn), respectively, taking into account the natural food contents. Proteinates used in the trial were analysed and described in terms of content and quality of different potential ligands. Piglet growth was not affected by any treatment. At the end of the trial blood samples were collected from eight pigs for each treatment. These animals were slaughtered and their livers were removed, weighed and analysed. Compared with SULF, PROT increased significantly plasma levels of Fe (25·1 v. 15·7 μ mol/l), haemoglobin (10·9 v. 10·4 g/dl) and the number of red blood cells (6·4 v. 6·1 millions per μ l) but the liver recovery of Fe was not affected by any treatment. In piglets receiving PROT the liver content of Cu and Zn increased significantly compared with those receiving SULF. On reducing the dosage, Cu in the liver significantly decreased with SULF but not with PROT and the amount of Zn decreased more with SULF than with PROT. The results may reflect a better availability of Cu and Zn when proteinates rather than sulphates were used as mineral supplements.

Varietal differences in rumen degradation of barley, wheat and hard wheat straws

The rumen dry-matter degradation of straw from nine varieties of barley, nine varieties of wheat and seven varieties of hard wheat was studied to provide further information on varietal differences and their relationships with agronomic characteristics. In all the cereals there were significant differences in in situ dry-matter disappearance between varieties. The range of differences was lower in hard wheat varieties compared with the other cereals. There were no significant correlations between straw degradability and plant height, days from sowing to heading and grain production and quality. Lignin concentration was significantly correlated to straw degradability (r = −0·937 in barley, −0·675 in wheat and −0·987 in hard wheat). Leaf had lower concentrations of lignin and higher degradability than stem in barley and wheat but the two fractions were similar in hard wheat straws. The differences in degradation between the most and the least degradable straw varieties of each cereal species were mainly due to differences in degradability of both the fractions whereas the role of leaf and stem proportions was of minor importance.

True dry matter digestibility of feeds evaluated in situ with different bags and in vitro using rumen fluid collected from intact donor cows

The aim of the study was to determine the comparability of the true dry matter digestibility (TDMd) achieved in situ with either traditional nylon bags (IS nylon) or synthetic filter bags (IS filter), and in vitro with either conventional bottles (CB) or the DaisyII incubation technique, using rumen fluid collected by oro-ruminal suction from intact cows. The four TDMd results were compared by linear regression. For each method, 11 feeds were incubated for 48 h in two separate incubations. The reproducibility of TDMd measurements was 97.9%, 95.1%, 98.8% and 96.0% for IS nylon, IS filter, CB and DaisyII, respectively. The determination coefficient, the slope (b), and the significant difference of the slope from unity, of the linear relationship between TDMd values (g/kg DM) were as follows: IS nylon v. IS filter, R2 = 0.97, b = 0.86, P = 0.02; IS nylon v. CB, R2 = 0.90, b = 1.02, P = 0.27; IS nylon v. DaisyII, R2 = 0.90, b = 1.06, P < 0.01; and IS filter v. DaisyII, R2 = 0.95, b = 0.98, P = 0.13. In situ filter bags and DaisyII underestimated the TDMd values compared with IS nylon bags and CB, respectively. In situ, the replacement of nylon with filter bags could simplify the procedure of analysis, with less manipulation of residuals and less labour, and offers the possibility to increase the number of samples analysed simultaneously. The close relationships found among methods suggest that rumen fluid collected from intact cows can produce in vitro estimates of TDMd at 48 h well correlated with those obtained in situ.

Effects of sugar beet pulp on growth and health status of weaned piglets

Abstract The effects on growth performance and on some health parameters due to the inclusion of sugar beet pulp in antibiotic-free diets for weaned piglets were evaluated on a commercial farm. A conventional diet (C) and one containing 120 g/kg of sugar beet pulp (SBP) were fed to 668 weaned piglets from 21 to 64±3 days of age. Every two weeks, live weight and feed consumption (FC) of the two groups were recorded by pens. Fecal samples were collected from 8 pairs of piglets for each treatment to evaluate the evolution over the time of the apparent digestibility of the nutrients, as well as the volatile fatty acids content and the microbial count in the feces. The dietary treatment did not affect FC. In comparison to C, SBP slightly reduced average daily gain over 36 to 49 (528 vs. 498 g/d; P<0.05) and 50 to 64±3 (677 vs. 631 g/d, respec-tively; P<0.01) days of age. Digestibility of NDF of diet C increased with age from 441 to 526 g/kg whereas that of diet SBP increased from 465 to 638 g/kg. The differences between diets became significant after 36 days of age (P<0.01). From 29 to 35 days of age higher contents of water (793 vs. 713 g/kg; P<0.01), acetic (322 vs. 206 µmol/g dm; P<0.01) propionic (108 vs. 81 µmol/kg dm; P<0.01) acids and lower counts for fecal-coliforms (6.9 vs. 8.2 log10/g; P<0.01), clostridia (1.3 vs. 2.3 log10/g; P<0.01) and Staphylococcus spp. (6.7 vs. 8.1 log10/g; P<0.01) were found in the feces of the SBP piglets compared to those of C. These differences progressively disappeared with time. Some piglets showed clinical signs of purulent arthritis and meningitis, but no signs of diarrhea were observed. The SBP group showed, with respect to C, a significantly lower number of piglet deaths caused by meningitis (15 vs. 30 ‰, respectively; χ2, P<0.05), and a significantly lower number of piglets removed because lack of growth (33 vs. 76 ‰, respectively; χ2, P<0.01). No clear evidence to explain this result was found, however it was concluded that the inclusion of 12% of sugar beet pulp in antibiotic-free diets can improve the health status of piglets with little effect on growth performance.

Oxidative stress indicators and metabolic adaptations in response to the omission of the dry period in dairy cows

The effects of dry period omission on oxidative stress and metabolic indicators around calving were studied. Seventeen Italian Friesian cows were randomly assigned to two groups, homogeneous for milk yield and parity, and managed either with a traditional 55-d dry off period (n=8) or continuously milked till parturition (n=9). Between 60 d before expected calving and 90 d after calving, body condition (BCS) was recorded and blood samples were collected to measure cortisol, urea, cholesterol, glucose, NEFA, triglycerides, insulin, malondialdehyde (MDA), total glutathione (GSH) and glutathione peroxidase (GPx) activity. BCS changes after calving were not different between the two groups. The normally dried group showed lower (P<0.05) glucose concentrations on day 7 before calving, greater (P<0.01) non-esterified fatty acid concentrations at 7 d and 15 d after calving, and greater (P<0.01) triglyceride concentrations for all the period before calving. On the other hand, plasma MDA was not different between groups. On average, plasma GSH concentrations were greater in continuously milked cows after calving (P<0.05), while plasma GPx was greater with continuous milking up to parturition (P<0.01). The results confirmed that omitting the dry period leads to an improved energy balance. The degree of oxidative stress was not detrimental for animal health, and the slight modifications of GPx observed prepartum were possibly related to continuous milk secretion. The differences in plasma GSH observed after calving may depend upon sulphur amino acid sparing in continuously milked cows.