Influences of dietary-reduced nitrogen (N) and phosphorus (P) on chemical body composition, N and P retention and health traits of contemporary barrows

Farmgate balances are used as a tool for monitoring nutrient surpluses at farm level. In Germany, preparation of farmgate balances is legally mandatory and also requires data on chemical body composition, especially concentration of nitrogen (N) and phosphorus (P), of farm animals. It is well known that increased N and P efficiency results in lowered N and P excretions with the manure and therefore mitigates negative consequences of high N and P release into the environment (e.g. eutrophication of surface waters), especially in areas with high livestock density. In this context, feeding N- and P-reduced diets can be a strategy for increasing N and P efficiency in fattening pigs. To investigate the influence of N- and P-reduced diets on chemical body composition of barrows and to update current used data basis, 8 barrows were slaughtered after a balance trial and their bodies were subjected to full body analysis. During the balance trial, pigs received the control diet (CON) meeting common nutrient requirements or the N- and P-reduced diet (NPred) in a three-phased feeding regimen (n = 4/diet, 3 weeks/phase). Pigs were slaughtered with an average live weight (LW) of 123.3 ± 7.5 kg and carcasses were manually dissected in four fractions. Fractions were analysed for nutrient concentration. Furthermore, organs were weighed individually and blood serum was sampled during exsanguination. Serum samples were analysed for clinical-chemical traits. Chemical body composition did not significantly differ between NPred- and CON-fed pigs. N concentration was 23.3 ± 0.3 and 24.5 ± 1.0 g/kg, P concentration was 5.2 ± 0.1 and 5.5 ± 0.4 g/kg in the empty body of NPred- and CON-fed pigs (p = 0.073, 0.164). N and P retention between the experiment's start and slaughter did not differ between the feeding groups (p = 0.641, 0.240). Variables related to liver integrity, energy metabolism and electrolytes were similar between CON- and NPred-fed pigs. Traits related to protein metabolism showed significantly reduced concentrations of urea and albumin in NPred-fed pigs (p = 0.013, 0.025), but no hypoalbuminaemia. Results suggest that N- and P-reduced feeding does not significantly affect chemical body composition of contemporary barrows.

Effects of dietary-reduced nitrogen (N) and phosphorus (P) on N and P balance, retention and nutrient digestibility of contemporary fattening pigs fed ad libitum

The reduction of nitrogen (N) and phosphorus (P) in fattening pigs' diets is one possible approach to lower N and P excretion in livestock farming relative to N and P intake. Due to the implementation of the European Nitrates Directive and the consecutive amendments to the German fertiliser legislation since 2017, N- and P-reduced diets for fattening pigs are becoming more and more important and are increasingly used in practice. To investigate the effects of such diets on N and P balance and retention as well as on nutrient digestibility of contemporary fattening pigs, a balance experiment was performed with eight barrows (average live weight = 61.5 ± 2.1 kg) which were surgically fitted with a simple T-cannula at the terminal ileum. The pigs received a control diet meeting nutrient requirements (CON) and an N- and P-reduced diet (NPred) ad libitum (n = 4/diet) in a 3-phased feeding regimen (3 weeks/phase). In the last week of each phase, faeces and urine were collected quantitatively for 5 days followed by a 2 × 12 hours collection of ileal digesta. Daily feed intake, live weight gain and feed-to-gain ratio did not differ between CON and NPred. NPred-fed pigs consumed 10.5% (p = 0.006) and excreted 28.3% (p = 0.028) less N than CON-fed pigs. Phosphorus excretion was lowered by 15.1% in NPred-fed pigs (p = 0.012). N and P retention did not differ between CON and NPred, but were elevated in comparison to other studies. N and P efficiency, expressed as nutrient retention divided by nutrient intake, was higher in NPred - than CON-fed pigs (N: 68 vs 60%, P: 54.2 vs 49.3%). Apparent post-ileal digestibility coefficient (DCpost-ileal) and apparent total tract digestibility coefficient (DCtotal) of crude protein were higher in NPred - than CON-fed pigs (p < 0.013), but apparent precaecal digestibility coefficient (DCpc) of crude protein was unaffected by diet. DCpc, DCpost-ileal and DCtotal of P were similar for CON- and NPred-fed pigs. NPred-fed pigs showed an elevated DCpc and DCtotal of organic matter, N-free-extractives and starch compared to CON-fed pigs. DCpc of calcium was also higher in NPred-fed pigs. In conclusion, the results suggest that N- and P-reduced feeding of fattening pigs remains an effective strategy to lower the N and P release into the environment. Furthermore, results indicate that N- and P-reduced feeding leads to a higher N and P efficiency in contemporary fattening pigs.

Insect Larvae Meal (Hermetia illucens) as a Sustainable Protein Source of Canine Food and Its Impacts on Nutrient Digestibility and Fecal Quality

Insect larvae meal has been proposed as a sustainable protein source for animal diets. This study aimed to provide information on including black soldier fly larvae meal (BSFL; Hermetia illucens) in comparison to poultry meal (PM) in the canine diet with regard to digestibility and fecal characteristics. In light of this trend, the levels of PM or BSFL meal were added to replace about 30% of dry matter of the basic extruded diet. Six Beagle dogs (BW 9.64 kg) were included in a cross-over experiment. Dogs fed a BSFL meal-based diet showed higher (p < 0.05) apparent protein digestibility (82.3%) compared to those offered a PM-based diet (80.5%). Apparent digestibility for fat was higher (p < 0.05) in groups fed the BSFL meal-based diet (94.5%) compared to those offered the PM-based diet (91.6%). The fecal consistency scores for dogs fed both diets were within an acceptable range (well-formed and firm). Fecal dry matter content was higher (p < 0.05) for dogs fed the PM-based diet (33.0%) compared to those offered the BSFL meal-based diet (28.0%). Including BSFL meal in dog food can be an appropriate source of protein without any negative effects on nutrient digestibility and fecal quality.

[Consequences of high ambient temperatures for lactating dairy cows - an issue under practical conditions in Northern Germany?]

OBJECTIVE

The aim of the presented study was to gather quantitative data regarding the impact of high ambient temperatures on dairy cows under practical conditions in southern Lower Saxony.

MATERIAL AND METHODS

In summer 2018 (from mid of July to end of September), the climatic conditions in the dairy barn as well as the temperatures of feeds (silages and partial mixed ration, PMR) and feed leftovers were recorded on the Farm for Education and Research of the University of Veterinary Medicine Hannover in Ruthe. Furthermore, daily dry matter intake (of PMR) and milk yield on herd basis as well as respiration rate and rectal temperature of 10 selected cows were measured as indicators for heat stress.

RESULTS

During a heat period (daily average temperature up to 27.9° C) dry matter intake (PMR) and milk yield were reduced by about 15 % and 8 %, respectively although ambient temperatures had already been relatively high at the beginning of the observation period (daily average temperature between 19.6 and 23.0° C). Daily dry matter intake of PMR was NEGATIVELY: correlated with daily average temperature-humidity index in the barn (Spearman's correlation coefficient: -0.774, p < 0.0001) and POSITIVELY: correlated with daily milk yield (Spearman's correlation coefficient: 0.766, p < 0.0001). Correlation coefficients were slightly higher when a 1-day time lag was considered (Spearman's correlation coefficient: -0.796 and 0.800, respectively; p < 0.0001). During the heat period hyperthermia (> 39° C) was frequently recorded in lactating cows (up to 100 %).

CONCLUSION AND CLINICAL RELEVANCE

The presented results indicate that heat stress in dairy cows may occur to a considerable extent under extreme climatic conditions also in the region of Northern Germany. In consequence, this is associated with a significant decrease in performance. As severe and long-lasting effects of heat stress on health and performance of dairy cows are well described in the literature, especially the temporarily high prevalence of hyperthermia should be taken seriously. Under these circumstances, differentiating between hyperthermia and fever is of special importance for veterinary practitioners.

[Feed refusal in fattening bulls because of maize silage contamination by Jimson weed (Datura stramonium)]

A sudden decrease in feed intake (within 24 hours) without an impaired general condition occurred on a bull-rearing and -fattening farm in western Germany in December 2017. One day later, some of the bulls displayed signs of ruminal tympany (free gas bloat) and the reduction in feed intake became more severe. The maize silage was recognized as the cause of the observed symptoms, because clinical signs first appeared after taking the silage from a different localization within the bunker silo. Maize in this particular section was harvested from a separate area previously affected by wind damage (numerous bent maize plants), where no crop protection (herbicide application) was performed. Fruits and seeds of Jimson weed were identified in the incriminated maize silage samples. Following replacement of the contaminated parts of the maize silage with non-contaminated material and treatment of the clinically affected animals (anti-tympanic medication plus live yeast preparation), the feed intake returned to the normal level and the affected animals recovered within 6 days. The cause of the symptoms was probably the anti-nutritive properties of Datura stramonium that affect the motor function of the gastrointestinal tract.

A by-product of swine slaughtering as a protein source in broiler diets: effects on performance, composition of excreta, litter quality and on foot pad health

Foot pad dermatitis (FPD) is of great concern in poultry industry, and dietary strategies are needed to improve foot pad health because of animal welfare and economic reasons. As the main factor for the development of FPD is the DM content of litter (consisting mainly of excreta; Kamphues et al., 2011), there are different dietary approaches to influence this disease pattern. In two consecutive trials, a total of 200 broilers were kept from day 7 until the 35th day of life. They were divided into four groups at each trial and fed with one of four experimental diets, based on wheat and corn mainly, but differing in the protein source: Group 1 was fed a diet with soya bean meal (SBM) as the main protein source, whereas Group 2, Group 3 and Group 4 were assigned to diets with 4, 8 and 12% of a protein-rich (66.7% CP in DM) by-product of swine slaughtering [Swine Protein Meal (SPM); in exchange for SBM]. The inclusion of 12% SPM resulted in a decreased dietary potassium content of about 3 g/kg diet (Group 1 vs. 4). Increasing dietary levels of the by-product (8 and 12%) led to lowered feed intake (Group 1 vs. 4: ~10%) and weight gain (Group 1 vs. Group 4: ~8.5%). Although highest DM contents of excreta and litter were determined in Group 4, foot pad health was not influenced positively as hypothesized. Remarkable was the observed 'stickiness' of excreta when the by-product was included in the diet at increasing levels, presumably due to the high proportion of bones in the by-product. In conclusion, substituting SBM by 4% of the by-product of swine slaughtering in broiler diets did not impair performance parameters, but led to the most favourable foot pad scores in this study.

Effects of a carbohydrase complex added in different inclusion rates in feeds for broilers on growth performance, digesta viscosity and foot pad health

Foot pad dermatitis (FPD) is a widespread disease in poultry and important for economic and animal welfare reasons. It is well recognized that using non-starch polysaccharide (NSP)-degrading enzymes can affect excreta/litter quality (not only in terms of moisture content but also regarding water evaporation) at high stocking densities and might help to prevent FPD and further negative effects of NSP. This study aimed to evaluate effects of a carbohydrase complex (CC) in different dietary inclusion rates on performance, digesta viscosity and foot pad health in broilers from 9 to 37 days of life. In total, 240 broilers were divided into 12 floor pens of 20 birds and received one of four different experimental diets. The four wheat- and soyabean meal-based diets only differed in the inclusion rate of CC: 0%, 50%, 100% and 500% of the recommended dose of CC (Endo-1,4-ß-xylanase and Endo-1,3(4)-ß-glucanase; 50 g/t). The addition of CC led to a significant decrease of digesta viscosity in the proximal small intestine, a tendency of improved feed conversion ratio, and significantly favoured FPD-scores (Treatment 2). At the higher tested inclusion rate of CC (500% of recommended dose), the FPD score was worser than in the treatments with 50% and 100% of the recommended enzyme dosage. No improvements among treatments were observed in terms of body weight and dry matter content of excreta and litter at the end of trial. The low positive effects on foot pad health in this study were presumably associated with the low NSP content in the experimental diets (soluble arabinoxylans: 7.38 g/kg as fed). In conclusion, the addition of the evaluated CC reduced digesta viscosity. An improvement of foot pad health could only be seen in the treatment with 50% of the recommended enzyme dosage in the diet.

The postnatal development of myelinated nerve fibres in the visual cortex of the cat: a stereological and electron microscopical investigation

With the aid of stereological procedures the development of myelinated nerve fibres (MF) was quantitatively investigated in electron micrographs of the visual cortex from animals of different ages: 36 days-old, the age at which fibres first appear, through adulthood. A short description of tissue treatment, methods and qualitative results is given. The following quantitative results are presented: 1. Myelinization begins at about the 36th day postpartum and is not completed by the 164th day. At this time a lack of about 20% MF can be observed. 2. The average diameter of MF decreases from 1.3 mum to 0.8 mum from day 36 to adulthood. 3. The first MF appear near the border of the album. 4. Beginning with the 55th day, small MF arise in layer I, showing two periods of growth. 5. The maximum MF density in the region of layer IV corresponds to the strip of Baillarger. Other aspects of visual cortex development are dealt with in the Discussion. The following conclusions can be drawn: a) The growing of in- and output-MF is completed first. b) The development of the internal connecting systems in layers I and IV begins a little later and is completed by the 5th month. c) The MF in layers II and III appear after the 4th month. Kaes (1907) has also described a continuation of MF growth in man lasting into the twenties.