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

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

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

Feeding behaviour, digestibility, energy balance and productive performance of lactating goats fed forage-based and forage-free diets

Six lactating Saanen goats have been used in a Latin Square design to evaluate a grass-based diet (G), a hay-based diet(H) and a nonforage diet (NF). On dry matter, grass and hay contributed for 55% of the diets and had 13.7 and 16.1%CP, 55.4 and 49.4% NDF, 38.0 and 31.6% ADF, respectively. Diet NF had beet pulp, cracked carob beans and whole cottonseedas main ingredients, with more than 75% of the particles greater than 2 mm.Independently of the dietary treatment, the goats spent more time eating than ruminating. Diet NF proved to be effectivein stimulating chewing activity, despite a trend for a lower chewing activity for eating (178, 185, 125 min/kg DMIfor diets G, H and NF, respectively), but not for ruminating (84, 80, 80 min/kg DMI for diets G, H and NF, respectively).Feed intake did not differ among diets, while regarding digestibility diet NF had the highest values for DM (74.1%), OM(75.7%) and non-fibrous carbohydrates (92.0%), but the lowest for ADF (44.5%). For treatments G, H and NF milk yieldswere 3011, 3688 and 3212 g/d (P2.96% (Pml, PC18:0, C18:1 and C18:3 in comparison to the other two diets. No difference among treatments was recorded for CLA.Intake energy was digested to a lesser extent for diet G (68.9, 70.0, 72.7%, Pquality forage. Urinary energy losses reflected the corresponding protein contents of the diets, while no difference wasrecorded for methane production. ME resulted higher for diet NF (60.0, 60.7, 65.1% of the intake energy, Pheat production and milk energy yield were similar in the three treatments. Diet NF had a higher ME content (11.13,11.26, 11.93 MJ/kg DM, P0.69) and NEl (7.20, 7.93, 8.30 MJ/kg DM).It is concluded from the study that a nonforage diet with an adequate amount of structured fibre could substitute a rationbased on poor quality forage in lactating goats; however, good forage seems to enhance milk performance to a greaterextent

Impact of red deer (Cervus elaphus) on forage crops in a protected area

During the last decades in Italy red deer (Cervus elaphus) density has locally reached very high values, with consequent serious problems due to the interaction with human activities, especially in protected areas. This study aims at quantifying the impact of red deer on herbaceous crops for forage production in a protected area in Northern Italy, that has been recently colonized by this species. To this aim, 14 exclusion enclosures on maize destined for whole plant silage production and 24 exclusion enclosures (not grazed, NG) on permanent meadows were established. For each of these sample plots (2 7 2 m), an adjacent control plot of identical surface area was established, freely available to red deer (grazed, G). Maize was harvested in September, whereas three grass cuts were harvested on meadows (May, July and August) and biomass production was weighed. Grass samples were collected, both in NG and in G plots, for chemical analysis. Red deer number was monthly estimated by night counts along fixed paths, using spotlights. The analysis of deer distribution allowed the distinction between two areas: High Density (HD: Northern area, with lower human disturbance, abundance of sheltered areas and an estimated deer density of 14\u201330 heads/km2) and Low Density (LD: Central and Southern areas, with an estimated deer density of 0\u20131.6 heads/km2). The percentage of maize plots with deer damage was significantly higher in HD than in LD area (83.3 vs 12.5%, respectively; P &lt; 0.05). In HD, red deer impact on maize crop was significant on plant height (NG = 250.75 \ub1 47.58 vs G = 136.87 \ub1 87.90 cm; P &lt; 0.05) and biomass production/plant (NG = 0.87 \ub1 0.42 vs G = 0.37 \ub1 0.39 kg/4 m2; P &lt; 0.05), whereas no significant effect was observed in LD. The percentage of plots of permanent meadows with deer damage did not differ between HD and LD areas. Significant losses were observed only in the second cut in the HD area for DM production, which was reduced by almost 14%. The chemical composition of the meadow forages showed only slight differences between G and NG plots (CP and NDF content significantly lower in G plots). The results obtained indicate that a high red deer density has an impact on the economic activity of farmers, particularly in term of maize losses (with estimated economic losses higher than \u20ac 20,000/farm/year), and suggest that appropriate management strategies, such as fencing of the crops at risk, are highly advisable

Digestibility, metabolic utilisation and effects on growth and slaughter traits of diets containing whole plant maize silage in heavy pigs

Two experiments were conducted to investigate the inclusion of high cut whole plant corn silage (HCCS) in diets for finishing heavy pigs on digestibility, metabolic utilisation, growth performance and slaughter traits. A control diet (CTR, containing maize meal, barley meal, extracted soybean meal and wheat bran, 550, 250, 90 and 80 g/kg DM, respectively) was compared with diet (CS) containing 200 g/kg DM of HCCS. The HCCS replaced wheat bran and part of maize meal in the CTR diet. In the first experiment, eight barrows were used in a two periods cross over design with periods of 21 d, included 7 d of total collection and three cycles of 24 h each in a respiratory chamber. In the second experiment, 28 barrows were divided into pairs on the basis of BW, kept in 14 pens and fed with the experimental diets until slaughter. Lower DM, OM, CP and energy total tract apparent digestibility was measured for the CS diet. Overall P retention as percentage of P intake was higher for CS diet, while N retention was similar for the two diets. Pigs fed CS tended to have a lower retained energy and the estimated NE of maize silage was 8.47 MJ/kg DM. Pigs fed the CS diets had a lower daily gain, a lower BW at slaughter and a reduction in the weight of back fat. The inclusion of HCCS increased the size of the stomach, the aNDFom concentration of stomach content and reduced the incidence of follicular gastritis