Livestock Research for Rural Development 25 (10) 2013 Guide for preparation of papers LRRD Newsletter

Citation of this paper

Mineral intake of sheep and goats grazing in the arid rangelands of northern Kenya

M I Lengarite, P N Mbugua*, C K Gachuiri* and L W Kabuage**

Kenya Agricultural Research Institute, KARI-Marsabit, P.O. Box 147, Marsabit, Kenya
moslengarite@hotmail.com
* Department of Animal Production, Faculty of Veterinary Medicine, University of Nairobi, Kenya
** School of Agriculture, Kenyatta University, Kenya


Abstract

A study was conducted in Merille location of Marsabit South District, Kenya to estimate the mineral intake of young sheep and goats. The most preferred forages consumed by animals were identified by direct observation of 120 sheep and goats. Each sheep/goat was observed for 10 minutes and complete bites of forages and parts consumed were recorded. Composite samples of ten most preferred forages were formulated based on bite counts and analyzed to determine concentrations of Ca, P, Mg, K, Na, Fe, Zn, and Mn. Mineral intake was then computed based on dry matter intake of animals and macro and micro- mineral content of forage composites.

In both seasons, the most preferred forages provided adequate intake of Ca, Mg and Fe to small ruminants. Sheep and goats also had sufficient intake of K (16.2 vs. 17.1 g kg-1 DM) and Mn (31.8 vs. 27.3 mg kg-1 DM) in the wet season and Zn (72.5 vs.63.5 mg kg-1 DM) in the dry season, respectively. However, sheep and goats showed inadequate intake of Na (0.39 vs. 0.49 g kg-1 DM) in wet season, marginal K (4.58 vs. 4.1 g kg-1 DM) and P (0.56 vs. 0.52 g kg-1 DM) in dry season, respectively. Zinc (15.0 mg kg-1 DM) intake in sheep and Mn (18.1 mg kg-1 DM) in goats during the wet and dry seasons, respectively was below their body requirements. In conclusion, young sheep and goats would need to be supplemented with P, K in the dry season and Na in wet season and sheep would also need Zn in the wet season and goats Mn in the dry season.

Key words: forages, intake,nutrient requirements


Introduction

Sheep and goats substantially contribute to the animal protein consumed in Kenya. Annual meat production is estimated at 84,000 tonnes of mutton and chevon worth KES 14 billion (GoK 2010). It is estimated that 60% of sheep and goats slaughtered in Kenya originate from the arid and semi-arid areas of the country (EPZ 2005). Albeit the large contribution of small ruminants to the consumption protein pool, the primary problem affecting livestock in Kenya was ranked as inadequate forage (Owen et al 2005).The productivity of these pastures is subjected to high variability between and within years, related to rainfall and seasons (Sanon et al 2007). In the arid areas, options of increasing livestock feed supply is limited (Coppock 1994) and increased knowledge on the quantity and quality of available feeds is prerequisite to correct the nutrient deficits.

Minerals are an important component of animal diets and are required by organisms to utilize other nutrients in the diet (Szefer and Nriagu 2007). In free grazing animals, minerals derived from natural feedstuffs are often inadequate and require supplementation to satisfy animal requirements (Sowande et al 2008). The amounts of nutrients, including minerals, in the forages greatly vary depending on soil, plant species and management factors (Haenlein 1991). Of the nutritional inadequacies, mineral deficiencies have adverse effect on both animal production and health (Schillhorn van Veen and Loeffler 1990). However, in the arid and semi-arid lands of Kenya, where the bulk of small ruminants are found, there is limited information on the mineral intake by grazing sheep and goats.

In free grazing systems, analysis of forages for mineral composition should be coupled with estimating their contribution to the mineral intake of animals. In free-grazing animals, obtaining herbage samples representative of that selected by goats or sheep is normally intricate (Aregheore et al 2006). The objectives of this study were therefore to determine the mineral profile of the composite representing the forages consumed by animals, estimate mineral intake and assess whether the forages provide adequate minerals to young sheep and goats in northern Kenya.


Materials and Methods

Study site

The study was conducted in Merille location of Marsabit South District in northern Kenya. It is characterized by an arid climate, with annual precipitation mean of 275 mm and air temperatures between 28-42oC. The area, has acidic soils with pH of 6.0 and low P of 4.5 ppm. The vegetation types found in the area include riverine woodland, bushed dwarf shrub and bushed grassland. The woodland vegetation comprise of mainly Acacia tortilis, Cordia sinensis, Salvadora persica. Acacia and Commiphora communities, Indigofera spinosa, Sericocomopsis hildebrandtii and Barleria acanthoides are the dominant species of the bush dwarf shrub land.

Forage sampling

The most preferred forage species selected by sheep and goats in the dry and wet seasons, were identified by direct observation of 120 growing animals (1-2 year old). During each season, sixty sheep and 60 goats were randomly selected from twelve herds grazing different pastures and directly observed for 10 minutes, between 08:30-11:30 hours for six consecutive days. Forage bites, species selected and forage parts consumed were noted and recorded. The number of feeding bites were summed up and ranked to determine the most preferred forages. For each season, ten most preferred forages were sampled from different grazing areas. The forage samples corresponding to parts consumed (leaves, tender twigs, flowers, seeds and pods) were randomly collected along the grazing path, at the peak of the wet season and late in the dry season. For each selected forage species, 10-15 plants were used to source 200 g which were bulked to 600g representative samples. The samples were air dried to constant weight at 70°C, milled to pass 1mm sieve and packed in sealed zip lock nylon bags.

Forage composite

During both wet and dry the seasons, the ten most preferred forages by sheep and goats were used to simulate the animals diet (Tables 1 and 2). The forage samples were mixed based on bite percent. The composite sample expressed on 100 percent basis, and weighing 100g (Tables 1 and 2) were carefully mixed at the time of formulation and prior to digestion.

Table 1: Most preferred forages by sheep and amount in forage composite  

Forage

Dry season

Amount (g)

Wet season

Amount (g)

Browses

Duosperma  eremophilum      

7.5

Crotalaria  fasicularis

3.40

 

Commiphora  africana

9.0

Indigofera  hochstetteri

4.49

 

Cordia  sinensis             

9.5

Indigofera spinosa

19.8

 

Indigofera  spinosa  

25.3

Indigofera  cliffordiana

2.63

 

Sericocomopsis  hildebrandtii

2.0

 

 

Grasses/herbs

Aristida  adscensionis

28.5

Commicarpus  stellatus

2.52

 

Commicarpus stellatus

2.2

Bracharia  leersiodes

14.9

 

Blepharis linariifolia

3.3

Tetrapogon  cenchriformis

20.4

 

Bracharia  leersiodes

4.1

Aristida  adscensionis

9.30

 

Tetrapogon  cenchriformis

8.6

Cenchrus  pennisetiformis

4.16

 

 

 

Mariscus  macropus   

18.4



Table 2: Most preferred forages by goats and amount in forage composite

Forage type

Dry season

Amount (g)

Wet season

Amount (g)

Browse

Acacia tortilis                 

6.28

Bauhimia taitenis   

3.43

 

Barleria acanthoides

4.27

Commiphora africana  

3.6

 

Bauhimia taitenis 

7.58

Grewia tenax

6.72

 

Combretum aculeatum

4.62

Indigofera hochstetteri   

8.70

 

Commiphora africana

8.06

Indigofera spinosa  

19.9

 

Cordia sinensis   

10.1

Lippia carviodora    

4.88

 

Indigofera  spinosa    

25.7

 

 

 

Maerua crassifolia

3.79

 

 

Grasses/herbs

Aristida adscensionis    

24.2

Bracharia leersiodes

33.5

 

Tetrapogon cenchriformis

5.40

Cenchrus  pennisetiformis

2.80

 

 

 

Mariscus  macropus

5.67

 

 

 

Tetrapogon cenchriformis

10.8


Laboratory analysis

Triplicate forage composite samples weighing 0.3 g were digested in tubes with sulfuric acid (H2SO4), salicylic acid and selenium as stabilizer. At relatively low temperatures (100°C) the organic matter in the samples were oxidized by Hydrogen peroxide (H2O2). After decomposition using H2O2, the digestion was completed by use of concentrated H2SO4 at elevated temperatures (330°C) under the influence of selenium as catalyst. The concentration of Ca, Mg, Fe, Zn, and Mn were determined by atomic absorption spectrophotometry (Perkin-Elmer AAS Analyst 100, USA) while flame photometer was used for K and Na analysis. Phosphorus concentration was determined colorimetrically (AOAC 1990).

Estimation of mineral intake

The mineral content of composite diet was used to compute mineral intake as:
Mineral intake = DM Intake (4 % LW, assumed to be on low quality diet) x macro (g kg-1DM) and micro (mg kg-1DM) mineral content in composite. The body weight of growing sheep (17 kg) and goats (16 kg) weighed in the field and estimated DM intake in sheep was (0.68 kg) and goats (0.64 kg).

Data analysis

The macro and micro-mineral forage data was subjected to a one-way analysis of variance and means between different seasons were compared by LSD using GenStat 12th edition (2010).


Results and discussion

Mineral profile of forage composite in sheep and goats

The macro and micro- mineral contents of composite samples simulating the diet of sheep and goats are presented in Table 3.

Macro-elements

The Ca and Mg concentrations in forage composite of sheep and goats were not influenced (P>0.05) by season. The concentrations of Ca and Mg were comparable to those reported by Aganga et al (2008) in Botswana, Kuria (2004) in northern Kenya and Temesgen and Mohammed (2012) in Ethiopia. Green plants are excellent sources of Mg, which is attributed to the presence of magnesium in the chlorophyll moiety (Wilkinson et al 1990). Thus, the shift in diets selected by sheep and goats in dry and wet seasons ensured consumption of diets rich in Mg.

In the composite of both animals, the contents of P and K were higher (P<0.05) in wet than dry season. The concentrations of P and K in forages decline with plant maturity and translocation of minerals to the root system (Reid and Horvath 1980). Kuria et al (2006) in Marsabit reported that about 22-50% of forages in camel diets were marginal in P and K. The acidic soils (pH 6.0) of the area favors uptake of K particularly during the wet season.

The forage composite of sheep had higher level (P = 0.045) of Na in dry (1.97±0.52 g kg-1 DM) than wet season (0.57±0.03 g kg-1 DM), while Na in goat composite was similar (P = 0.094) in both seasons. In the wet season, the low levels of Na underpins the report by Minson (1990) that most tropical pastures contains less than 1.5 g Na kg-1 DM.

Table 3: Mineral content (DM basis± SE) of composite forage in dry and wet seasons in sheep and goats

 

Sheep

 

Goat

 

Element

Dry

Wet

SEM

Prob.

Dry

Wet

SEM

Prob.

Ca, g kg-1

16.7a

16.9a

2.7

0.974

15.3a

22.8a

2.5

0.099

P, g kg-1

0.87a

2.57b

0.033

<0.001

0.80a

2.23b

0.151

0.003

Mg, g kg-1

3.2a

2.23a

0.281

0.072

3.33a

2.77a

 0.323

0.283

K, g kg-1

6.73a

23.8b

0.467

<0.001

6.4a

26.7b

0.642

<0.001

Na, g kg-1

1.97a

0.57b

0.369

0.045

1.37a

0.77a

0.194

0.094

Fe, mg kg-1

790a

1001a

166

0.42

905a

712a

220

0.568

Zn, mg kg-1

107a

22.0b

8.79

0.002

99.3a

18.6b

4.01

<0.001

Mn, mg kg-1

37.1a

46.8a

2.49

0.06

28.2a

42.7a

6.86

0.21

 abMeans within a row of same animal lacking common letters differ (P<0.05)

Micro-elements

The Fe concentrations in forage composite of sheep and goats were similar (P>0.05) in both seasons. The high values of Fe can be attributed to soil contamination of forages (Underwood and Suttle 1999). During the dry season, dusty winds are common feature of the area and in the rainy season floods contaminate pastures in the riverine valley. Also, acidic soil conditions of the area favour availability and plant uptake of Fe (Khan et al 2006). However, the contents of Fe were similar to those reported by Kuria et al (2004) in mineral sources of camels in western Marsabit, Kenya.

The forage composites of sheep and goats, had higher contents of Zn in dry (P<0.05) than wet season. In dry season, the levels of Zn were remarkably higher than the mean of 36 mg Zn kg-1DM reported in most tropical grasses (Minson 1990). Ramírez et al (2006) also reported high levels of Zn (161 mg kg-1DM) in some browse species in north eastern Mexico.The concentration of Zn in herbage is mostly influenced by Soil pH, soil texture, soil mineral concentration and botanical composition (Espen et al 2005).

The Mn contents in forage composite of sheep were not affected by season (37.1±3.46 vs. 46.8±0.64 mg kg-1 DM). In the case of goats, although not significant (P = 0.21) manganese concentration tended to increase in wet season (42.7±5.78 mg kg-1 DM) than dry season (28.2±7.8 mg kg-1 DM). In both seasons, Mn concentrations in sheep and goat composites were lower than those reported by Rubanza et al (2005) in Tanzania, Temesgen and Mohammed (2012) in Ethiopia. However, during the wet season Mn in sheep and goats composite were comparable to the values of 43.47-44.47 ppm (DM) reported by Shamat et al (2009) in browses selected by camels in western Sudan. The Mn concentrations in plants were highest in leaves (Marković et al 2009) and acidic soils (Underwood and Suttle 1999).

Estimated mineral intake of young sheep and goats from forage composite

The estimated macro and micro-mineral intake and requirement of young sheep and goats are presented in Table 4.

Table 4: Estimated mineral intake in dry and wet season (DM basis) and requirement in young sheep and goats

 

Mineral intake/day

 

 

Sheep

 

Goats

 

Mineral requirements1

Element

Dry

Wet

Dry

Wet

Sheep

Goats

Ca, g kg-1

11.4

11.5

9.8

14.6

2.0

3.5

P, g kg-1

0.56

1.75

0.52

1.43

1.6

2.45

Mg, g kg-1

2.18

1.52

2.13

1.77

1.2

0.8-2.5

K, g kg-1

4.58

16.2

4.1

17.1

5

5

Na, g kg-1

1.34

0.39

0.88

0.49

0.9

0.8-1

Fe, mg kg-1

537

681

579

456

30-50

30-100

Zn, mg kg-1

72.5

15.0

63.5

11.9

20-33

>10-50

Mn, mg kg-1

25.2

31.8

18.1

27.3

20-40

20-40

 

1Requirements for growing sheep and goats (Kessler 1991; Heinlein 1980; NRC 1981; NRC 1985).

Macro-elements

Irrespective of season, sheep and goats intake of Ca was above the recommended requirement of 2.0 and 3.5 g kg-1 DM respectively (NRC 1981; NRC 1985). Thus sheep and goats consume adequate levels of Ca. In both seasons, goats P intake was below the recommended requirement 2.45 g kg-1 DM (NRC 1981). However, growing sheep in the dry season consumed less than recommended while in wet season they consumed levels above the recommended requirement of 1.6 g kg-1 DM (NRC 1985). Low P intake can affect the concentration of Mn in the liver (Neathery et al 1990). In dry and wet seasons, sheep and goats consumed adequate levels of Mg to satisfy their body requirements.

However, for K, sheep and goats with daily requirement of 5 g kg-1 DM (NRC 1981) consumed high levels during the wet season, but had marginal deficiency in the dry season (Table 4).

In the dry season, sheep and goats with a Na requirement of 0.8 and 0.8-2.5 g kg-1 DM respectively, consumed sufficient levels of Na to certify their body requirement. However, in the wet season Na intake in sheep and goats were below the recommended requirement. Imbalances of Na and K intake in the wet season can inhibit the ATP dependent Na+-K+ pump and energy metabolism in animals (Underwood and Suttle 1999).

Micro-elements

In both seasons, sheep and goats consumed levels of iron above the requirements of 50 and 100 mg kg-1 DM in sheep and goats, respectively (NRC 1985; Kessler 1991; Haenlein 1980). High levels of Fe may cause nutritional problems of decreasing phosphate absorption (Zaman et al 2011). However, symptoms of P deficiency were not observed in the young sheep and goats.

In the wet season sheep consumed low levels of Zn, but during the dry season the intake of Zn in growing sheep was above the maximum requirement of 33 mg kg-1 DM (NRC 1985). However, goats in both seasons consumed adequate levels above the requirement of >10 mg kg-1 DM (Kessler 1991; Haenlein 1980). Therefore growing sheep and goats consumed adequate levels of Zn in the dry season, but sheep seems to suffer from Zn deficiency in the wet season.

Both sheep and goats, with a requirement of 20 mg Mn kg-1 DM (NRC 1985; Kessler 1991; Haenlein 1980), consumed adequate levels in the wet season. During the dry season, Mn intake in goats was below the minimum requirement. Manganese is poorly absorbed in ruminants and antagonism with high dietary Ca can reduce Mn bioavailability (Spears 2002). However, Mn requirements are substantially lower for growth than for optimal reproductive performance (McDowell and Arthington 2005).


Conclusions


Acknowledgements

The authors wish to thank Kenya Arid and Semi-Arid lands (KASAL) project for funding this study, University of Nairobi and KARI-NARL for laboratory analysis.


References

Aganga A A and Mesho E O 2008 Mineral contents of browse plants in Kweneg District in Botswana. Agricultural Journal 3(2) 93-98.

AOAC 1990 Official Methods of Analysis, 15th Edition. Association of Official Analytical Chemistry, Inc., Washington, DC., USA.

Aregheore E M, Ofori A L and Rere T 2006 Studies on grazing behaviour of goats in the Cook Islands: The Animal-plant complex in forage preference/palatability phenomena. International Journal of Agriculture Biology 2, 147-153.

Coppock D L 1994 The Borana plateau of southern Ethiopia: synthesis of pastoral research development and change, 1980-91 International Livestock Center for Africa, ILCA Systems Study No.5, Addis Ababa Ethiopia.

Espen G, Arvid S, Anne K B, Turid S and Sissel H 2005 Factors affecting the concentration of Zn, Fe and Mn in herbage from organic farms and in relation to dietary requirements of ruminants. Acta Agriculturae Scandinavica, Section B - Soil & Plant Science, www.tandfoline.com/toc/sagb20/55/2, Volume 55, Issue 2, pp. 131-142.

EPZ-Export Processing Zones Authority 2005 Meat production in Kenya. Also accessed at www.epzkenya.com/Userfiles/File/Meatindustry.pdf in September 2005.

GenStat software 12th edition 2010 www.vsni.co.uk.

GoK-Government of Kenya 2010 Agricultural sector development strategy 2010-2020, p.14.

Haenlein G F W 1980 Mineral nutrition of goats. Journal Dairy Science, 63: 1729-1748.

Haenlein G F W 1991 Advances in the nutrition of macro and microelements in goats. In: Proceedings of the Seventh Annual Conference on Goats Production, Monterrey, NL. Mexico, pp. 290-320.

Khan Z I, Hussain A, Ashraf M and McDowell L R 2006 Mineral status of soils and Forage in South western Punjab-Pakistan: Micro-minerals. Asian-Austr.J.Animal Sceince, Volume 19, No. 8: 1139-1147.

Kessler J 1991 Mineral nutrition of goats. In: Morand-Fehr, P. (Ed) Goat nutrition, Vol.46 EAAP Publication, pp.104-119.

Kuria S G, Wahome RG, Wanyoike M M and Gachuiri C K 2006 Effect of mineral supplement on plasmaconcentration of Camels (Camelus dromedarius) in Kenya, International Journal of Agriculture and biology, 168-171.

Kuria S G 2004 Mineral nutrition on settlement (Manyatta) based milk camel herds among the Rendille community of Northern, PhD thesis, University of Nairobi, Kenya, pp. 93-99.

McDowell L R and Arthington J D 2005 Minerals for Grazing Ruminants in Tropical regions, 5th Edition, University of Florida, Gainesville, F1.

Minson D J 1990 Forage in ruminant nutrition. Academic press Inc., London, UK.

Marković J, Štrbanović R, Cvetković M, Andelković B and Živković B 2009 Effects of growth stage on the mineral concentrations in Alfafa (Medicago sativa L) leaf, stem and the whole plant. Biotechnology in Animal Husbandry 25(5-6), pp. 1225-1231.

Neathery M W, Crowe N A, Miller W J, Crowe C T, Varnadoe J L and Blackmon D M 1990 Influence of dietary Aluminium and phosphorus on zinc metabolism in dairy calves. Journal of Animal Science (68), 4326-4333.

NRC 1981 National Research Council. Nutrient Requirements of Goats: Agora, Dairy and Meat Goats in Temperate and Tropical Countries, National Academy Press. Washington, D.C.

NRC 1985 National Research Council. Nutritional requirement of sheep. 6th ed. Natl. Acad. Press. Washington, D.C.

Owen E, Kitalyi A, Jayasuriya N and Smith T 2005 Livestock and wealth creation. Improving the husbandry of animals kept by resource-poor people in developing countries. Nottingham, England, p.74.

Ramírez R G, González-Rodríguez H, Ramírez-Orduña R, Cerrillo-Soto M A and Juárez-Reyes A S 2006 Seasonal trends of macro and micro minerals in 10 Browse species that grown in northeastern Mexico. Animal feed science and technology, Elsievier 128, pp.155-164.

Reid R L and Horvath D J 1980 Soil chemistry and mineral problems in farm livestock. A review. Animal Feed Science. Technology, 5: 95-167.

Rubanza C D K, Shem M N, Bakengesa S S , Ichinohe T and Fujihara T 2005 The content of macro and micro minerals of deferred forages in silvo-pastoral fodder banks (Ngitiri) of Meatu district of central north-western Tanzania. Livestock Res. for rural development 17(12).

Sanon H O, Kabore´-Zoungrana C and Ledin I 2007 Behaviour of goats, sheep and cattle and their selection of browse species on natural pastures in a Sahelian area. Small ruminant research 67, pp.64-74.

Shamat A M, Bakiker I A, Mukhtar A M S and Ahmed F A 2009 Seasonal and regional variation in Mineral content of some Important Plants species selected by Camels (Camelus dromedaries) in Arid and Semi-arid Lands (ASAL) of Sudan. Journal of Applied Sciences Res,5 (10): 1676-1684.

Schillhorn van Veen T W and Loeffler I K 1990 Mineral deficiency in ruminants in sub Saharan Africa: A review. Tropical Animal Health and Production 22(3):197–205.

Sowande O S, Odufowora E B, Adelakun A O and Egbeyale LT 2008 Blood minerals in wad sheep and goats grazing natural pastures during wet and dry seasons. Arch. Zootec. 57 (218):275-278.

Spear J W 2002 Trace mineral bioavailability in Ruminants. In: 11th Meeting of the International Organization, “Trace elements in Man and Animals” (TEMA), Berkely, Califorlia, June 2-6, 2002, USA.

Szefer P and Nriagu J O 2007 Mineral components in foods, chemical and functional properties of food components series., CRC press, Tylor and Francis group,FL, USA, pp.163-195.

Temesgen D and Mohammed Y K 2012 Preferably browsed forage species by camels (Camelus dromedarius) and their mineral contents in Jijiga district, Eastern Ethiopia. Livestock Research for rural development. Volume 24, Article # 45.

Underwood E J and Suttle N F 1999 The mineral nutrition of livestock 3rd edition, CABI publishing, p.68.

Wilkinson S R, Welch R M, Mayland H F and Grunes D L 1990 Magnesium in plants: Uptake, distribution, function and utilization by man and animals. In: Metal ions in biological systems, Vol.26, compendium onmagnesium and its role in biology, nutrition and physiology, Mercel Dekker, New York, USA, pp.3-56.

Zaman S, Husain F and Badshah L 2011 Micro-mineral contents in eight forage shrubs at three phonological stages in a Pakistan’s rangeland. African Journal of Plant Science, Volume 5 (10), pp.557-564.


Received 13 February 2013; Accepted 13 September 2013; Published 1 October 2013

Go to top