Effects of constant vs variable dietary protein content on milk production and N utilization in dairy cows.

Forty-two lactating Holstein cows were divided into two groups, control (C) and test (T), and used in a cross-over design. In each group cows were also divided in three subgroups on the basis of milk yield: low (L), medium (M) and high (H). C cows were fed a diet with 15.4% CP on DM. T cows were fed three diets with the CP content (% DM) adjusted to milk yield (13.6, 15.2 and 17.2 for diets TL, TM and TH). At the highest level of production TH diet improved milk yield (kg/d) (38.9 C vs 41.0 TH) and FCM (kg/d) (39.6 C vs 40.6 TH) (P<0.05). No differences were detected for TL and TM diets compared to C. For L and H subgroups milk urea (mg/dl) was increased by the higher CP diets (28 C vs 24 TL; 30 C vs 36 TH; P<0.05). N efficiency (milk N, %N intake) was higher with lower CP diets (22 C vs 25 TL; 32 C vs 29 TH) and for increased milk yield. An adequate CP content of the diet enhances milk production in high yielding dairy cows, but an excessive amount of dietary N increases milk urea and N excretion

Influence of high levels of beet pulp in the diet on endocrine/metabolic traits, slaughter dressing percentage, and ham quality in Italian heavy pigs

Seventy two Landrace x Large White barrows were divided into three groups and fed different diets: a control traditional diet based on cereals (C) and two with 15 or 30% dried sugar beet pulp (BP15 and BP30, respectively). Animals weighed 106 kg at start and 167 kg at the end of the experiment. Feeding was restricted (2.5 kg DM/head, on average). The aim of the present experiment was to investigate the influence of high levels of beet pulp in the diet of fattening heavy pigs on some endocrine/metabolic traits, on the slaughter dressing percentage and on some parameters related to meat quality, composition and on the ham quality, after 14 months of seasoning. During the experimental period, jugular vein blood samples were collected from C and BP30-fed pigs and plasma was analysed for several metabolic traits. BP30 diet initially increased the plasma glucose level and decreased free amino acids (P<0.05), but this difference disappeared at the end of the experimental period, when insulin level was decreased (P=0.06) by beet pulp administration. During the entire period, 30% beet pulp diet increased total protein and albumin levels (P<0.001) and decreased urea (P<0.05) without affecting plasma leptin. At slaughter, pigs fed BP30 diet were lighter (P<0.001) and with a lower dressing percentage (P<0.001) in comparison with the other two treatments. Pigs fed BP30 diet also had lower ham and loin weights (P<0.05) (but similar ham and loin percentages) and higher liver weight (P<0.05), liver/carcass ratio (P<0.001), gastrointestinal- tract weight (P<0.001) and gastrointestinal-tract/carcass ratio (P<0.001). Pigs fed C diet had a higher dressing percentage in comparison with pigs fed BP15 diet (P<0.01), but no other significant difference was found between pigs fed diets C and BP15. At slaughter, liver samples were taken from C and BP30-fed pigs in order to evaluate the effect of the diet on liver composition. BP30 diet increased dry liver weight (P<0.05) and liver fat content (P<0.01). The iodine value and the fatty acid composition of the backfat revealed no significant difference between pigs fed the control diet and those fed the high fibre diets. Finally, considering the economic importance of ham production, the characteristics of the seasoned hams were evaluated. No difference was observed on ham quality. In conclusion, feeding a diet with a high percentage of dried sugar beet pulp alters protein and energy metabolism and slaughter parameters, without affecting the quality of the seasoned ham

Nutritive value of different hybrids of sorghum forage determinedin vitro

Eight hybrids of sorghum forage were tested in large plots of two farms in two consecutive years to evaluate their chemical characteristics, nutritive value and yield as a possible substitute for maize silage. Two or three cuts were made depending on climatic conditions. On forage samples taken at ensiling chemical analyses and 24 h gas production were performed, to predict the NEl content. In comparison with maize silage, the sorghum hybrids registered higher protein (13.7% on DM) and NDF (62.6% on DM) contents. Interestingly, the fibre fraction had a low lignin content (3.1% on DM). NEl content ranged from 4.53 to 5.28 MJ/kg DM, the latter for the hybrid with the lowest NDF content. Hybrid effect was significant for ash, NDF, ADF and NEl contents, whilst cut effect was significant for EE, CP, NDF and ADF. Yield was strongly influenced by fertilisation; when the latter was applied, it was in the range of 10-18 t DM, 1.7-2.8 t CP and 47-88 thousand MJ NEl per hectare, as a sum of the 2- 3 cuts. Sorghum forage seems to be a possible alternative to the fibrous maize silage fraction in diets of lactating cows, and an excellent forage for the rations of dry cows and heifers

Methane yield from dry and lactating cows diets in the Po Plain (Italy) using an in vitro gas production technique

The aim of the study was to measure total gas and methane (CH4) production from 30 total mixed rations (TMRs) fed to dry and lactating cows in 20 commercial dairies in the Po Plain (Italy). Samples were analysed for chemical composition, in situ 48 h fibre digestibility (NDFD) and in vitro gas production (GP) and CH4 concentration at 24 h of incubation. NDFD of TMRs from dry and lactating cows was identical (52.1%; P=0.995). The TMRs fed to dry and lactating cows differed for GP (43.0 and 54.4 mL/200 mg DM, respectively; P<0.001) and CH4 (7.24 and 8.85 mL/200 mg DM, respectively; P=0.001), but not for CH4 as percentage of GP (24.3 and 23.7%, respectively; P=0.286). The data were analysed dividing the TMRs into quartiles depending on starch:ADF ratio; the average ratios of the groups 1, 2, 3 and 4 were 37, 77, 116 and 138, respectively. Increasing starch:ADF ratio determined a higher GP: 42.2, 51.4, 55.1 and 56.2 mL/200 mg DM for groups 1, 2, 3 and 4, respectively (P<0.001), whilst CH4 (mL/200 mg DM) was lower (P<0.001) for group 1 (7.12) in comparison with the others (8.82 on average). Acetate (% on total VFA) decreased for increasing starch:ADF ratio (P=0.009), whereas butyrate tended to increase (from 8.11 to 9.23% on total VFA; P=0.069) and the acetate:propionate ratio to decrease (from 3.35 to 3.09; P=0.082). The lack of a higher CH4 concentration in GP from diets richer in fibre might be attributed mainly to the relatively short time of incubation

Effects of benzoic acid on nitrogen, phosphorus and energy balance and on ammonia emission from slurries in the heavy pig

The effects of two dietary levels of benzoic acid on nitrogen, phosphorus and energy balance were evaluated in the typical Italian heavy pig during the last phase of growth. Six Landrace x Large White barrows of 125 kg body weight (BW) on average were used in a repeated 3x3 Latin Square design and housed in metabolic cages to collect faeces and urine separately, in 3 collection periods of 7 days, after 14 days of adaptation. The animals were individually housed in open circuit respiration chambers to determine the energy metabolism. The dietary treatments were as follows [% on dry matter (DM)]: i) diet C (control): 14.2 crude protein (CP), 3.7 EE, 13.8 NDF; ii) diet B05: diet C plus 0.5% benzoic acid; iii) diet B10: diet C plus 1.0% benzoic acid. DM fed was fixed at 6.8% BW0.75. Apparent digestibility was similar among treatments for all the parameters studied. Nitrogen (N) retention was 35.8, 37.4, 41.6% of intake N for C, B05 and B10, respectively, with no significant difference. Energy and phosphorus balances were not influenced by dietary treatments. Ammonia nitrogen emission from the slurry, expressed as a proportion of the initial slurry nitrogen, was decreased (P=0.049) by the inclusion of benzoic acid in the diet: 35.2, 28.1, 26.2% for C, B05, B10, respectively. The addition of benzoic acid to the diet determined a numerically decrease of the urinary pH. In conclusion, the inclusion of benzoic acid in the diet of the heavy pig is beneficial to the environment without effects on N, phosphorus (P) and energy balances

Typical edible non-dairy animal products in Africa from local animal resources

This review aims to identify the main typical non-dairy edible products of animal origin available in Africa, describing their production processes and their strengths and constraints. Farm animals are mainly raised in an extensive, family-run system; there is, however, a significant development of intensive poultry production. Meat products are usually obtained by drying, but meat and/or offal can also be stored as stuffed products and can be additionally treated by smoking and/or curing. The increasing poultry production provides eggs and meat at low price. The small-scale/ family farms are managed mainly by women and children, with a positive social impact. The assets and limits of local breeds and of extensive versus semi-extensive or intensive production systems are discussed. Seafood are an essential source of proteins, minerals and micronutrients. Due its high perishability, the proportion of cured fish in this continent is higher than the world average. Wildlife can supply high-quality meat, but attention must be paid to the vulnerable/ endangered species and to the sanitary aspects of this food chain. Insects are traditionally con- sumed in Africa, supplying very cheap highly nutritive food, with low environmental impact. Finally, a variety of honey and other bee products, including some Slow Food praesidia, are described. From the point of view of the respect of biodiversity and ecosystems, local culture, accessibility and nutritional requirements, animal productions in Africa are usually carried out in a sustainable way; however, the low efficiency of most traditional production systems represents an important limit, also in relation to export opportunities

In vitro effects of different levels of quebracho and chestnut tannins on rumen methane production, fermentation parameters, and microbiota

Both condensed and hydrolysable tannins (CTs and HTs, respectively) have the ability to reduce enteric CH4 production in ruminants. However, the precise mechanism of action is not fully understood. Among the proposed hypotheses are the reduction of ruminal digestibility, direct control action on protozoa, reduction of archaea, and a hydrogen sink mechanism. In this in vitro study, which simulated rumen fermentation, two additives, one containing CTs (70% based on DM) from quebracho and one with HTs (75% based on DM) from chestnut, at four levels of inclusion (2, 4, 6, 8% on an as-fed basis) were added to the fermentation substrate and tested against a negative control. Both types of tannins significantly reduced total gas (GP) and CH4 (ml/g DM) production during the 48 h of incubation. The lower GP and CH4 production levels were linked to the reduction in dry matter digestibility caused by CTs and HTs. Conversely, no significant differences were observed for the protozoan and archaeal populations, suggesting a low direct effect of tannins on these rumen microorganisms in vitro. However, both types of tannins had negative correlations for the families Bacteroidales_BS11 and F082 and positive correlations for the genera Prevotella and Succinivibrio. Regarding the fermentation parameters, no differences were observed for pH and total volatile fatty acid production, while both CTs and HTs linearly reduced the NH3 content. CTs from quebracho were more effective in reducing CH4 production than HTs from chestnut. However, for both types of tannins, the reduction in CH4 production was always associated with a lower digestibility without any changes in archaea or protozoa. Due to the high variability of tannins, further studies investigating the chemical structure of the compounds and their mechanisms of action are needed to understand the different results reported in the literature