Adoption Of Forage Legume Technology To Improve Dairy Production

The Zimbabwe Dairy Sector fails to meet the National domestic demand for milk of 120 million litres per annum. The deficit is imported using scarce foreign currency. The natural grazing (veld) creates a quality forage production gap from April to November, annually. Fodder production and conservation as hay or silage is expensive and difficult for Smallholder dairy farmers.

Adoption Of Forage Legume Technology To Improve Dairy Production

ADOPTION OF FORAGE LEGUME TECHNOLOGY TO IMPROVE DAIRY PRODUCTION:By Professor N. T. Ngongoni, ZOU Head of Applied Research, cell: <0773879816>; e-mail:,<ngongonint@gmail.com>

Abstract: The Zimbabwe Dairy Sector fails to meet the National domestic demand for milk of 120 million litres per annum. The deficit is imported using scarce foreign currency. The natural grazing (veld) creates a quality forage production gap from April to November, annually. Fodder production and conservation as hay or silage is expensive and difficult for Smallholder dairy farmers.

A possible solution to the problem is to reinforce the veld and established artificial improved dryland or irrigated pastures with high protein nitrogen-fixing forage legumes that were tested and evaluated for Zimbabwean conditions, listed below.In spite of the glaring advantages of adopting forage legume technology as givenin this relevant and exciting review of this technology in ruminant animal production; it has a number of constraints to its adoption and full utilization. The seed is unavailable and expensive; its establishment and sustained management is difficult for smallholder farmers.

Some forage and browse legumes (like Stylosanthesguianensis andLeucaenaleucocephala, repectively) cause bloat while others have anti-nutritional factors (likeMucunapruriens,with L-Dopa; and Desmodium uncinatum, with tannins) which may limit voluntary feed intake or interfere with the processes of degradation and true small intestinal digestion (Kumar and D`Mello, 1995).

INTRODUCTION:

The domestic demand for whole milk in Zimbabwe is 120 million litres per year(ZADF, 2017).The highest annual milk production recorded in the recent past, in 2016, was 65.36 million litres. The deficit of 54.64 million litres to meet the domestic demand is currently being imported from South Africa and other neighboring countries at a cost of scarce foreign currency to the nation. The milk deficit exists in spite of the central role of milk both as a wholesome food and as our best weapon to fight Protein-Energy Malnutrition (PEM), which is rampant in rural Zimbabwe especially among school-going children.

We therefore have a moral obligation and a financial responsibility to broaden the milk production base of Zimbabwe, to promote high levels of milk consumption, to increase both the yield and the compositional and hygienic quality of milk; and promoting economic viability of dairy production to upscale rural livelihoods. When milk yields are as low as 11-14 litres per cow per day, the dairy production being pursued is not an economically viable and attractive farming enterprise especially when the milking cows are acquired through a loan as is the case in the ZOU Community-based research site of Chitomborwizi Smallholder dairy Network.

To improve economic viability of dairying in Zimbabwe, there is need to inject greater reliance on quality forages in dairy nutrition (Pascoe, 1975), coupled with reduced reliance on increasingly expensive conventional commercial dairy concentrates supplied by stockfeed companies.

In tropical and subtropical environments, ruminants which subsist solely on veld (natural pasture) experience varying degrees of undernutrition, especially during the long dry seasonfrom April to November (6-8 months).

When the rainy season starts in November, the shooting grass increases to peak levels, of crude protein (5-6%) and crudefibre [Neutral Detergent Fibre(NDF)], 40-60% by April before starting to decline for CP or cross-linking with lignin and silica for NDF. It is clear that the quality and quantity of veld fluctuates in rhythm with seasonality of rainfall with the high protein falling to low protein (1-3% CP) and NDF rising to over 60% during the dry season in June-July (Ngongoni and Manyuchi, 1993).

Fortunately, early researchers (Bembridge, 1961; ward, 1968; Richardson, Oliver and Clarke, 1977; 1979) observed that supplementation of cattle on veld with nitrogen-rich supplements alleviates the effects of undernutrition and improves animal performance. However, due to the ever increasing cost of the conventional commercial protein supplements, it is cheaper to reinforce the veld or natural pasture with high protein nitrogen-fixing forage and browse legumes.

Research work conducted at Grasslands research station proved that reverted grazing land can be made more productive through reinforcement with high protein nitrogen-fixing forage legumes; for more and better feed for ruminants (Clatworthy, 1984).

Forage legumes are selected because of their ability to fix nitrogen in the soil to increase protein content of companion grass,increase protein content of grazed herbage and extend the grazing period due to their deep roots (Maclaurin, 1998). So the forage legumes:-

-Increase the nutritive value of grazed herbage due to their high protein contents.

-remain productive over a long period, thus extending the grazing season due to their deep rootedness.

-are generally high yielding because they fix their own nitrogen requirements.

-stimulate greater production per head in terms of increased beef and milk production; calving rates; weaning weights; live weight gains and reduced mortality rates.

-replace fertilizer nitrogen in the soil-plant-animal relationships.

-reduce the use of expensive concentrates in dairy production systems.

-replace expensive dry season supplements in beef production systems.

-reduction of pen-finishing costs through optimal growth of feeders on pasture.

-production of high carcass quality in fattened, feeder and slaughter animals.

-increase farm carrying capacity (CC) through increased production of herbage per unit area (either or both of summer and winter carrying capacity) can be increased, especially where land is limiting.

It is clear that adoption of forage legume technology improves veld productivity and benefitialpasture utilization. Further improvement of veld productivity comes from veld replacement with fodder crops that produce more fodder per unit of land than the veld plants and they can be planted with or without forage legumes.

So after maximum forage reinforcement of veld we can get more productivity from our veld from planting dryland or irrigated improved pastures; again with or without the forage legumes. In dryland situations, grass x legume pastures with about 40% legume content fix about 80-100kg N/ha, but dry matter production is lower than where we apply high levels of nitrogen (250-350kg N/ha to grass pasture alone.

LEGUME SPECIES SUITABLE FOR USE IN REVERTED VELD (NATURAL PASTURE) OR DRYLAND IMPROVED PASTURE REINFORCEMENT IN ZIMBABWE.

A number of species hasbeen researched for the above purposes and those recommended are suggested below:-

Fine Stem Stylo…………………………….Stylosanthesguianensis

Stylosanthesscabra

Townsville StyloStylosantheshumilis

Stylosantheshippocampoides

Stylosantheshamata

Siratro……………………………………………Macroptiliumstropurpureum

Silverleafdesmodium…………………….Desmodium uncinatum

Greenleaf desmodium……………………Desmodiumintortum

Archer…………………………………………….Macrotylomaaxillare

Roundleaf cassia……………………………..Chamaecristarotundifolia

Kenya White clover………………………….Trifoliumsemipilosum

Tamar white clover…………………………..Trifoliumrepens

Cooper glycine………………………………….neonotoniawightii

Beit lotononis……………………………………lotonosisbainesii

Sunhemp……………………………………………Crotalaria juncea

Lucerne………………………………………………Medicago sativa

Cowpeas…………………………………………….Vignaunguiculata

High protein browse legumes are more suitable for semi-arid and arid environments because they are deeper- rooted than forage legumes.

We have some common browse legumes which have been widely accepted like:-

Lucaena………………………………………………..Lucaenaleucacephala

Acacia boliviana…………………………………….Acacia boliviana

Acacia angustissima……………………………….Acacia angustissima

Sesbania …………………………………………………Sesbaniasesban

Pigeon pea……………………………………………….Cajanascajan

Calliandra………………………………………………….Calliandracolothyrsus

The fodder browses can be planted throughout the veld in rows 4 metres apart or again in rows but throughout the pasture; or concentrated in small patches in a small part of the paddock or planted along contour ridges for field and paddock boundaries.

  1. What is needed is the laboratory nutritive evaluation of the foliage from all these forage/browse legumes and to do intestinal true digestibility of the rumen undegraded plant feed; as well as the amino acid degradability and absorption. There is need also to carry out feeding trials to test the protein from some of the species. There is need to research into anti-nutritional factors (anf`s) in these forage/browse legumes and their ability to support rumen microbial protein production (RMPP) and the effect of both anf`s and RMPP on Animal Production.

Where high protein forage legumes are used to reinforce improved dryland artificial pastures to save on nitrogen fertilizer costs, Bloat can be a problem which necessitates its control by use of bloatguard.

Bloat is the distension of the rumen as gas accumulates so as to result in the collapse and death of a dairy animal which consumed legume-rich herbage. Bloat may not be so much due to excessive gas production trapped in foam in the rumen than to the failure of the animal to eructate becausecertain pharmacologi-cally active substances in herbage inhibit gut muscles causing failure to eructate (McDonald, Edwards and Greenhalgh, 1988)[End].

REFERENCES:

1.Bembridge, T.  (1961).

2.Clatworthy, J. N.; (1984). Effect of reinforcement of native grazing with Silverleafdesmodium (Desmodium uncinatum) on dry season performance of beef steers in Zimbabwe. Tropical Grasslands 18:198-205.

3.McDonald, P., Edwards, R. A. and Greenhalgh, J. F. D. (1988). Animal Nutrition Fourth Edition, ISBN 0-470-20791-4 (Wiley, USA only).

  1. Ngongoni, N. T. and Manyuchi, B. (1993). A note on the flow of Nitrogen to the abomasums in ewes given a basal diet of star-grass hay supplemented with graded levels of deep litter poultry manure. Zimbabwe Journal of Agricultural Research 31 (2) 135-140 ISSN 0251-1045.
  2. Richardson, F., Oliver, J. and Clarke, G. P. Y. (1977). 
  1. Richardson, F., Oliver, J. and Clarke, G. P. Y. (1979).
  2. Zimbabwe Association of Dairy Farmers (ZADF), (2017). Fifth Annual General Meeting in Nyanga.Dairy industry double production by 2020. (Ed.) KudzanaiSharara. Sunday mail 08-07-2018