Natural resource use in grassland-based ruminant systems of Sub-Saharan Africa Fundamental research meets applied science

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1 Natural resource use in grassland-based ruminant systems of Sub-Saharan Africa Fundamental research meets applied science Uta Dickhoefer Institute of Agricultural Sciences in the Tropics Animal Nutrition and Rangeland Management in the Tropics and Subtropics

2 Context Ruminant production in SSA greatly based on (natural) grasslands in diverse farming systems Predicted increase in domestic ruminant populations due to rising (global) demand for animal-derived food Future challenges in natural resource use Conflicting land uses Increasing stocking rates Greater intra- and inter-annual variability in climate Political, public, and private requests for more sustainable systems Need for applied and fundamental research from different disciplines 2

3 DFG-funded research project (DFG research group 536, ) Matter fluxes in grasslands of Inner Mongolia as affected by stocking rate Stocking rate (sheep/ha * 90 d) Continuous 1st year Alternating 2nd year SR 1 SR 2 SR sheep 3.0 sheep 4.5 sheep SR 4 SR sheep 7.5 sheep SR sheep 3

4 Forage biomass and nutritional quality in ANPP (g DM/m²) 70 In vitro digestibility (g/100 g OM) Alternating 65 Alternating Continuous 60 Continuous Stocking rate during the grazing season (sheep/ha) (Schönbach et al. 2011; Plant Soil 340, ) 4

5 Feed intake of sheep No differences in intake and digestibility Digestibility (g/100 g OM) OM intake (g/kg 0.75 LW * d) Digest. (ALT) Intake (ALT) domalt OMIALT Digest. (CON) Intake (CON) domcon OMICON Stocking rate during the grazing season (sheep/ha) (Dickhoefer et al. 2014; Range. Ecol. Manage. 7, ) 5

6 Semivariance (cm²) Semivariance (cm²) Grazing behavior of sheep Prolonged daily grazing time at higher stocking density Patch grazing is affected by climate and management Higher CP in forage of grazed than rejected and ungrazed patches Ungrazed Lightly grazed Heavily grazed Continuous Ungrazed Lightly grazed Heavily grazed Alternating Distance (m) Distance (m) 5 0 (Lin et al. 2011; Appl. Anim. Behav. Sci. 129, 36-42; Ren et al. 2015; Agric. Ecosyst. Environ. 213, 1-10) 6

7 Grazing behavior of dairy cattle in the Peruvian Andes Grazing observations (n/200 m²) Crude protein (g/kg DM) Pictures: Franziska Steiner

8 Animal-environment interactions in grazing systems Alternating grassland use mitigated negative effects of high grazing intensity in a temperate grassland Great adaptive capacity of grazing ruminants to variable mass and quality of available forage Factors driving patch and plant (part) selection and how they are affected by climate, management, or animal characteristics poorly understood Ecological consequences of selective (patch) grazing on grassland ecosystem functioning must be evaluated 8

9 Nitrogen partitioning in lactating dairy cows of El Salvador No differences in feed conversion efficiency and nitrogen partitioning N excretion (g/g N intake) Urine Feces Milk Soybean Urea Jackbean Cowpea 9

10 Protein metabolism in ruminants N in hair, skin etc. NH 3 NH 3 N in body protein Dietary N Microbial N Urinary N Endogenous N Dietary N Milk N Fecal N 10

11 Urinary excretion of purine derivatives Rumen Feed intake Milk Microbial mass Purine-N Microbial N = Endogenous sources 0.85 Body tissue, foetal growth, etc mm/kg LW 0.75 Urine Stomach 70 mg N/mM (Values for European cattle; Chen & Ørskov 2004) Small and large intestine Feces 11

12 Composition of microbial pellets (µm purine bases/mg N; n = 12) Liquid-associated c c ab ab a bc QTE (% of DM intake) QTE: P<0.001 QTE x T: P=0.241 Solid-associated ab b ab ab ab a QTE (% of DM intake) QTE: P=0.028 QTE x T: P=0.034 (Dickhoefer et al. 2016; J. Anim. Sci. 94, ) 12

13 Estimates of duodenal microbial nitrogen (MN) flow Shifts in the microbial consortium or development stage of microbial cells - Higher purine contents in liquid- than solid-associated microbes (Martin-Orue et al. 2000) - Species-specific purine concentrations (Obispo & Dehority 1999) - Higher nucleic acid contents at high growth rates (Rodriguez et al. 2000) QTE dosage (% of DM intake) Urinary PD (mm/d)* Duodenal MN flow (g/d) Chen & Orskov (2004) Liquid-associated Solid-associated * According to Ahnert et al. (2013); PD, purine derivatives; MN, microbial nitrogen. (Dickhoefer et al. 2016; J. Anim. Sci. 94, ) 13

14 Conclusions & outlook Method development and validation for tropical environments in SSA - Feed evaluation - Nutrient digestion and metabolism - GHG emissions and nutrient excretion In vivo and in situ assessments of available feeds and of the digestive capacity and nutrient requirements of (local) ruminant species/breeds; Better understanding of animal-environment interactions (not only) under grazing situations; Prediction of the effects of feeding and grazing management on natural resource use in grassland-based ruminant systems 14

15 Thank you! Partly funded by: DFG (Research group 536) DAAD (PROPERU ) BMBF ( A) Fiat Panis Foundation

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17 Räumliche Heterogenität der Vegetation und des Verhaltens von Rindern Wahrscheinlichkeit des Grasens (n/m²) Oberirdische Biomasse (kg FM/ha) Kiel, 26. Mai 2016 Uta Dickhöfer 17

18 Räumliche Heterogenität der Vegetation und des Verhaltens von Rindern Wahrscheinlichkeit des Grasens (n/m²) Bodenbedeckung von Festuca sp. (%) Kiel, 26. Mai 2016 Uta Dickhöfer 18

19 Räumliche Heterogenität der Vegetation und des Verhaltens von Rindern Wahrscheinlichkeit des Grasens (n/m²) Rohproteingehalt (g/kg TM) Kiel, 26. Mai 2016 Uta Dickhöfer 19

20 tity and quality.. Grazing behavior of sheep Prolonged daily grazing time at higher stocking density Selective patch grazing as affected by climate and management Higher CP in forage of grazed than rejected and ungrazed patches 20

21 Forage biomass and nutritional quality 200 ANPP (g DM/m²) 180 Alternating Continuous Stocking rate during the grazing season (sheep/ha) (Schönbach et al. 2011; Plant Soil 340, ) 21

22 Nitrogen partitioning in lactating dairy cows of El Salvador No differences in feed conversion efficiency and nitrogen partitioning Urine Feces Milk 319 g/d 313 g/d 286 g/d 304 g/d Soybean Urea Jackbean Cowpea 22

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24 Animals and feeding Three ruminally fistulated heifers (502 ± 21 kg LW) Basal diet (on fresh matter basis) 2.6 kg/d grass hay 2.6 kg/d concentrate feed 60 g/d minerals 4.5 kg/d DM intake Quebracho tannin extract (QTE) via rumen cannulae Dietary QTE concentration (% of daily DM intake) QTE dosage (g/d) (g/kg LW)

25 Animal-environment interactions in grazing systems Great diversity of feedstuffs with variable composition; Characterization of nutrient composition and degradability for evaluation of protein value; Ecological Agronomic Feeding - Biodiversity and chemical composition of diet strongly influence - Palatable partitioning biomass of nutrients Excretion - Ground of N cover via urine and feces and its conversion -to Nutritional product protein quality Some - Water/nutrient of these factors storage influencing feed protein degradation - Nutrient are intake passage rate, degradabilit crude - Soil protein erosion synthesis - Performance Most - GHG of these emissions. factors are influenced by animal genotype and/or feed characteristics Nevertheless, advanced feed evaluation methods have been developed for temperate 25 fe