Subject: SILAGES FROM TROPICAL FORAGES: NUTRITIONAL QUALITY AND MILK PRODUCTION

                 Aminah A., Abu Bakar C. and Izham A.

                            MARDI, Malaysia
                       E-mail: aminahal@mardi.my


Introduction

   There   is   a  need  for  silage  making  technology  under   local
conditions,  especially  in those areas experiencing  drier  months  or
where monsoonal conditions restrict the routine cutting of forages. The
need  for  silage  making  is  even more significant  in  dairy  cattle
feeding, where the demand for uniform and high quality feed is of great
importance.   The tedious daily harvesting of green forages  throughout
the year also posed problems with smallholders, particulary when family
labour is not sufficient.

   The  objective  of  this paper is to evaluate  the  performance  and
suitability  of six tropical grasses and three forage crop  for  silage
making and a feeding trial for milk production.


Methods

   Six   grasses  viz.  setaria  (Setaria sphacelata  var.  splendida),
signal (Brachiaria decumbens), humidicola  (B.humidicola), MARDI  Digit
(Digitaria  setivalva), Napier (Pennisetum purpureum)  and three  crops
viz.  (Zea mays) forage sorghum (Sorghum vulgare x S. bicolor)  and  S.
almum were planted.  The grasses were cut at 6 weekly intervals.   Corn
was harvested at 75 days, forage sorghum at 70 days and S. almum at  63
days after planting.

   Fresh  samples  were  taken for DM% and water-soluble  carbohydrates
(WSC)   (Dubois  et al. 1956) and for silage making in the  laboratory.
The  silage  samples were analysed for pH, lactic acid  analysis  (MAFF
1973)   and  physical characteristics.  In the second  experiment,  six
multi-parous Sahiwal-Friesian cows in mid-lactation were used  to  test
three dietary treatments in a double switch over experiment (Cochran et
al.  1941).   Treatments were levels of silage in the  diet  in  direct
substitution  for  cut  fodder as follows  a)  fodder  ad  libitum,  b)
fodder+silage (50:50) ad libitum and c) silage ad libitum.  In addition
each  animal  received six kg of concentrate once daily.  Feed  samples
were taken once  weekly and composited by cow-period.  Feed intake  and
milk production were recorded daily.


Results and Discussion

   The  mean  value of the WSC and the DM% in the crops and quality  of
silage produced (pH and lactic acid content) are shown in Table 1. Corn
and  forage  sorghum produced good silage with pH <4.0 and lactic  acid
level  with the values of 2.72 and 3.7%, respectively (Table  1).   For
the  grasses, it was found that without additives, setaria  and  Napier
can  be  turned  into  acceptable silage with  pH  of  4.07  and  3.96,
respectively. The pH of the grass silage was reduced with the  addition
of 4% molasses (Table 1).

   The  nutritional composition of sorghum silage and guinea grass used
in the second experiment are shown in Table 2. Treatment means for feed
DMI,  milk yield and feed efficiency are in Table 3.  Intake of DM from
roughage  was higher (P<0.05) on treatment B than either A  or  C.  The
higher roughage intake of treatment B appears to be attributable  to  a
stimulatory  effect of silage on intake.  The difference in  the  total
DMI  reflects  differences in roughage DMI.  Expressed as percent  body
weight,  total DMI on the respective treatments were within  the  range
2.0  to 2.4%.  Average daily milk yield was higher (P<0.5) for cows fed
sorghum silage compared with control. The difference in milk yield  was
13%  between treatments C and A. Mean feed efficiency value of cows  on
the silage-based diet was nearly twice as good as either treatment B or
the control group A (Table 3).

   Of  the  crops,  forage sorghum and corn can be made into  excellent
silage  without additives.  Grasses are suggested to be cut at about  6
weeks  regrowth.   Napier  and setaria can be ensiled  into  reasonable
silage,  but  the  quality  can be improved with  the  addition  of  4%
molasses before ensiling.  As for the second experiment, sorghum silage
appears to be a better feed than the average guinea grass commonly  fed
to  lactating cows in this country.  This is reflected in its effect on
milk yield and feed efficiency.


Table 1. Silage Made from Tropical Grasses and Forage Crops
======================================================================
Crop Species      Silage      Silage 4 %            Quality
                               molasses
               -----------   -------------  --------------------------
                DM%    WSC    pH   lactic               pH    lactic
                        %         acid (%)                   acid (%)
----------------------------------------------------------------------
Grasses                                                          
S. splendida   15.30  6.17   4.07   2.47      Good     3.64    1.96
B. decumbens   20.37  8.64   5.07   1.08      Poor     3.37    1.87
B. humidicola  20.85  2.35   5.32   1.26      Poor     3.31    2.03
D. setivalva   18.21  1.26   4.32   1.46      Poor     3.31    2.83
P. purpureum   15.77  9.88   3.96   2.53      Good     2.98     nd
P. maximum     19.35  3.03   4.71   1.84    Moderate   3.27    2.74
                                                                 
Crops                                                            
Z. mays        21.20  22.99  3.72   2.72    Very good            
S. vulgare x   21.35  11.69  3.68   3.75    Very good            
  S. bicolor                                                       
S. almum       18.40   nd    4.40    nd     Moderate             
----------------------------------------------------------------------
nd: not done


Table 2. Chemical composition of feedstuffs (%)
======================================================================
Feedstuff         DM    CP   TDN    CF    EE   NFE   Ash    Ca    P
----------------------------------------------------------------------
Guinea grass     24.1  11.7  61.6  33.6   2.4  46.1  6.2   0.57  0.27
Sorghum silage   29.4   8.7  60.1  33.4   2.6  51.0  4.2   0.47  0.17
Concentrate      91.2  23.5  77.2   5.5  11.6  54.7  4.7   0.57  0.36
----------------------------------------------------------------------


Table  3.  Feed intake and efficiency and milk yield for the  different
treatments
======================================================================
Variables                                    A         B         C
----------------------------------------------------------------------
Feed DM Intake (kg/d)                                           
Roughage                                   4.95b     6.22a     4.50b
Concentrate                                5.40      5.40      5.40
Total                                     10.35b    11.63a     9.90b
DMI Per 100 kg BW                          2.1       2.4       2.0
Milk Yield (kg/d)                          7.01c     7.54ab    7.93a
Feed Efficiency (kg total DMI/kg milk)     2.16b     2.65b     1.37a
----------------------------------------------------------------------
The values within rows with different letters are significantly
different (P<0.05)


References

Dubois,  M.,  Gilles, K.A., Hamilton, J.K., Rebers, P.A. and Smith,  F.
  (1956).  Calorimetric method for determination of sugars and  related
  substances. Anal. Chem. 28(3):350-356.
MAFF  (1973). The determination of lactic acid in silage juice.  Manual
  of   Analytical   Methods.  Technical  Bulletin   27,   Ministry   of
  Agriculture and Food, United Kingdom.
Cochran,  W.G., K. M. Autrey and C.Y. Cannon. (1941). A double  change-
  over  design  for  dairy cattle feeding experiments.  J.  Dairy  Sci.
  24:937-951.
  POSTER: Silage quality and losses due to ensiling of Napier grass,
Columbus grass and maize stover under small holder conditions in Kenya
                                   
                   P.J.M. Snijders and A.P. Wouters
                                   
                   E-mail: p.j.m.snijders@pr.agro.nl


Introduction

   On  behalf  of  the  National  Dairy  Development  Project,  several
ensiling  experiments were conducted at the National  Animal  Husbandry
Research  Centre  (NAHRC) at Naivasha, Kenya, in the period  1983-1989.
The  aim  of  the  experiments was to develop  methods  and  techniques
suitable  for  smallholders for the ensiling of Napier grass,  Columbus
grass  and  maize  stover  to overcome feed shortages  during  the  dry
season.


Materials and methods

   The following six series of ensilage experiments were conducted:
   
Series A: 2  silages  of chopped, wilted Napier grass with  or  without
          addition  of  molasses, ensiled in an number of netted  nylon
          bags and placed inside a larger silage clamp

Series B: 6  pits of wet long or chopped Napier grass with addition  of
          3.5% or 6% or without molasses

Series C: 4  pits of wet long or chopped Napier grass with addition  of
          3.5% molasses or MUM (molasses/urea mixture)

Series D: 6  pits of wet long or chopped Napier grass with addition  of
          3% molasses

Series E: 4 pits of wet long or chopped Columbus grass with addition of
          3% molasses

Series F: 3  pits  of  chopped maize stover or maize stover mixed  with
          lablab, without additive.

   Silages  were made in small earthen pits in quantities varying  from
1000  to  2000  kg  fresh  material, thus  more  or  less  representing
conditions  for  small-scale farmers. Sides and top  of  the  pit  were
covered with 2 m wide polyethylene plastic sheets covered with a  layer
of about 50 cm of sand on top and sides


Results

   Percentage non-edible silage (mouldy and rotten silage) varied  from
0  to  2.5%, indicating that sealing with polyethylene sheet  and  soil
cover was good. Levels of butyric acid and contents of ammonia nitrogen
often  were below 0.3% and 12 respectively for silages of wilted Napier
grass and wet chopped Columbus grass with the addition of molasses  and
for silage of maize stover. These fermentation characteristics indicate
good  silage quality. Smell was good as well. For some wet Napier grass
silage  and for silages made with addition of MUM of unchopped Columbus
grass, results were less good.

   Long,  unchopped Napier grass wilted for one or two  days  to  about
30%  dry  mater  and  with  the addition of molasses  and  with  proper
compaction, often resulted in good silage as well.

   Dry  matter  losses  due to ensiling of Napier grass  averaged  15.2
4.2%. Losses were lower for silages made of grass wilted for one or two
days  and higher for silages made of wet unchopped grass and grass with
the  addition  of MUM. For wet Columbus grass, there was also  a  clear
positive  effect  of  chopping. Average dry matter losses  for  ensiled
maize stover were 8.1%.

   Losses  of  crude protein averaged 16.9%, but variation  was  large,
partly due to sampling errors. Losses were lower for wilted silages and
much higher for silages with the addition of MUM.

   In  vitro organic matter digestibility decreased due to ensiling and
was more than 10 units lower in case of poor quality silages. For well-
preserved silages, the decrease in digestibility was often limited to 5
units  or less. Losses of digestible organic matter for Napier  silages
averaged 28.57.9%. Losses were lower for wilted silages and much higher
for wet silages of series D and silages made with the addition of MUM.

   Results  show that under smallholders' conditions, good  silage  can
be  made.  Poor  quality  silages  of poorly  digestible  Napier  grass
however, will not meet maintenance requirements of animals.


Conclusions and practical recommendations

1. Under small farmer's conditions,  good silage  can be made, provided
  that  air-tight sealing with plastic polyethylene sheets is  applied,
  with at least a cover  of 50 cm of soil  on top and sides of the pit,
  and with good drainage of rain water. Ensiling and covering has to be
  completed within one day.

2. As shown by good fermentation characteristics and smell, wilting one
  or two days  to reach a dry  matter content of  30% often  results in
  good silage,  especially  when molasses  is added.  Wilting to  a dry
  matter content of more than 30%, or wilting of old stemmy material is
  not recommended, because of the higher weather risks and difficulties
  with compaction.

3. Dry matter losses  due to ensiling of wilted  or wet, chopped Napier
  grass with the addition of molasses could be limited to 15%.

4. Dry matter losses of silages  made of wilted, un-chopped long Napier
  grass are probably  slightly higher than  from chopped  Napier grass.
  Provided  proper compaction, addition of molasses,  air-tight sealing
  and covering with at least  50 cm soil, making silage of long, wilted
  Napier grass may be a good alternative for smallholder conditions.

5. Although it is not very  clear from the  limited experience provided
  by  these experiments, addition of 3% molasses to wet and long wilted
  Napier  grass  will probably  be sufficient  to obtain  good  quality
  silage,  especially  when  hand-mixed  through   chopped  silage.  To
  increase chances for good quality  silages addition rates of up to 6%
  are suggested when molasses is applied in the silage pit on layers of
  grass.  For chopped,  wilted Napier  grass and for  chopped  Columbus
  grass, addition of molasses can be lower.

6. MUM as an  alternative  additive for molasses  does not produce good
  silages.

7. Silages of  chopped Columbus grass  with molasses and chopped  maize
  stover without molasses made good silage.  Dry matter losses appeared
  to be lower compared to Napier grass.

8. Because of a  higher risk for  leaching,  dilution of  molasses with
  water in order to ease application  should not exceed a 1-to-1 ratio.
  A relatively small quantity of molasses should  be used at the bottom
  layers of the pit, and more to be added to the middle and top layers.

9. Losses  of  crude  protein  and digestible organic matter  were  not
  accurately  measured in  these  experiments,  because of  the limited
  number of  samples and  because  of  sampling errors.  Based on  good
  quality  silages in these  experiments, losses  are about 15% and 25%
  for crude protein and digestible organic matter respectively.

10. Poor  silages  of  overgrown  Napier  grass  will  at  best  supply
  sufficient energy for maintenance. Feeding overgrown Napier grass  as
  standing hay, or mulching might be a better alternative then.  Proper
  storage  and  utilisation  of crop residues  like  maize  stover  and
  preserving  feeds like sweet potato vines, fodder beets,  cassava  or
  fodder trees may prove better in those situations.
     POSTER: Wet Season Silage Production at Taminmin High School

                              Chris Regan

           Northern Territory Department of Primary Industry
              and Fisheries (NT DPIF), Darwin, Australia
                  E-mail: Chris.Regan@DPIF.nt.gov.au


1. Feed Resources in the Wet Tropics

   The  main  limiting factor for ruminant production in  the  Tropical
Top  End  of Australia is the lack of good quality feed throughout  the
year.  Seasonal rainfall provides a period of abundant herbage  at  its
peak  nutritional value during the wet season, followed by a period  of
lower  quality mature herbage in the dry season. It makes sense to  try
and  conserve  the  abundance of good quality  vegetation  when  it  is
available  in  the wet, and use it later in the dry season  when  plant
growth  is  severely restricted, natural feed is in short  supply,  and
commercially available feed is relatively expensive.

   This  is  exactly what has been done at Taminmin High School,  which
is  located near Humpty Doo, approximately 40 km South East of  Darwin,
Northern Territory, Australia. The precise location is 12° 24' S,  131°
15' E.


2. Taminmin's Silage Program

   As  a regular part of their farm management strategy, Taminmin makes
baled  silage  during late January or early February each year.  Making
hay  at  this time is not an option because it is too difficult to  dry
the plant matter to the required 85%DM or more.


Fig 1. Baled Silage being transported on the Taminmin Trailer

	[Figure 1 available in PDF and HTM files]


   On  the  other  hand, wet season pasture can be baled at  lower  dry
matter  (DM) content and higher moisture than hay, wrapped  in  plastic
film and allowed to ferment into silage.

   Almost  any pasture can be made into silage, but the best silage  is
made  from the best pasture. At Taminmin, silage is regularly made from
Pangola grass, Cavalcade legume, and Wynn Cassia legume.

   The  trick  is  to watch the weather, then cut only  enough  pasture
that  you  can comfortably wilt, bale, wrap and stack in a  single  day
without any rainfall.


3. A Typical Day of Making Silage

   As  long as we are confident of getting a rain free day we go ahead.
Trial and error has taught us to process no more than 1.5 hectares.

   Check  with the Weather Bureau. They regularly track tropical storms
by  radar and are very competent predictors of storm incidence, arrival
times,  and intensity/duration. We have found their accuracy  decreases
as distance inland increases, but for the cost of a phone call they are
a terrific advisory service.

   Pasture  is  cut at 0900 hours. Sunrise is usually just after  0700,
and  the  two  hours  is  enough time to get most  of  the  free  water
evaporated from the pasture.

   A  second tractor forms up the windrows almost immediately. This  is
usually done by 10.30. We turn the windrows over just once, starting at
11.00.  This  is  usually  done by 12.30. We sample  the  windrows  and
estimate  the  dry DM content. This is easily done in 10 mins  using  a
microwave oven, but we are lucky enough to have a probe (Farmscan 2180)
to  do this in the field. We start baling as soon as the DM content  is
40%  or  more. (Actually, the last two seasons the contractor has  made
this  process  much more efficient: he has used a mower/conditioner  to
cut, condition, and windrow in one operation. This has also allowed the
cut pasture to dry out quicker.)

   We  get about 60 bales, and baling is normally finished by 1730.  We
start wrapping as soon as the bales are formed. This takes longer  than
baling, but is completed just before 1900.

   We  do  not provide any additives such as molasses, urea, or  lactic
acid  bacteria inoculant. Our research has shown that the cost  of  the
additive  cannot  be  justified. Weight increases of  stock  being  fed
silage  with  or  without  additives are not  significantly  different.
However, it is extremely important to wilt the material to about  40%DM
before  baling.  Ensiling wet material (e.g. less  than  30%  DM)  will
almost  certainly  result in production of poor  quality  silage,  high
amounts of wastage, and a high degree of stock rejection.

   It  is  a  very busy day that we usually repeat, weather permitting,
two or three times in 7-10 days. The end result is a harvest of between
70-80  tonnes of reasonable quality feed stored away for use  later  in
the dry season.

   After baling, we spread fertiliser. Late wet season rains give us  a
good  regrowth  which can be grazed or harvested  a  second  time.  The
second harvest is usually made into hay as per normal practice for  our
area.


4. The Benefits

* Fodder conservation from our improved pastures has increased  by more
  than 40%.

* We get two harvests instead of one (and a grazing period).

* The same small areas previously  were only lightly grazed  and turned
  into  hay  during  May: although  it  was  good  quality hay,  it  is
  nutritionally lower than the silage made in February.

* Weed  control is improved. Small amounts of weed that are present are
  ensiled  before they  head out.  Consequently we spend  less time and
  money  on  weed  control, whilst continually giving  our  pastures  a
  competitive advantage.

* The  process  manages Wynn Cassia really well. Wynn Cassia makes good
  silage, but very poor hay (see section below).

* Our  feed costs during  the dry season  are dramatically  reduced. We
  still buy supplements,  but the vast bulk of  the feed is provided by
  the conserved silage.

* Conserved  forage is a cash crop: we have always sold our excess hay,
  but also having baled silage for sale improves our management options
  as well as our annual income.


5. The Disadvantage

   The  major  difficulty  with  the program  is  the  need  to  use  a
contractor.  The  making of silage is not difficult,  but  the  program
depends  on  having  the  equipment readily  available.  Although  late
January   /  early  February  is  a  time  of  inactivity  for   baling
contractors,  most  do not have wrapping machines,  and  anyhow  it  is
costly  to  move the equipment about in order to process  a  relatively
small amount of forage.

   Hopefully,  as more people try this management strategy, costs  will
reduce,  and efficiencies due to processing larger amounts  of  forages
can improve.


6. Special Benefit: Wynn Cassia

   This  vigorously growing tropical legume has a positive benefit  for
soil  nitrogen  content,  and is an excellent  ground  cover  for  weed
control. However,

* cattle and buffalo  only eat  Wynn Cassia  reluctantly  under  normal
  grazing conditions, and

* it is extremely difficult to make into hay. This is because the plant
  is very leafy. The leaves  shatter easily as they dry out.  They also
  shatter  and  drop  off  when  moving  through a baler.  If  you  are
  successful  at all in making a bale of Wynn Cassia hay,  it  will  be
  nearly all stem.

   The  positive  benefit is that Wynn Cassia silage is easy  to  make:
the  higher moisture leaves do not shatter, and the bale is much easier
to  form. Silage made from a mixed Wynn Cassia / grass pasture is  even
easier  to make, and usually better quality. Secondly, stock love  Wynn
Cassia  silage: they accept it immediately, and eat it all when  it  is
presented.


7. For the Technically Minded

   A  summary for the silage quality, including nutrition data is shown
in the table.

Table 1. Harvest Summary: Baled Silage
-----------------------------------------------------------------------
                          Pangola        Cavalcade    Wynn Cassia
-----------------------------------------------------------------------
Dry Matter (%)              42               45             52
Digestibility (%DM)         57               55             58
Metabolisable Energy
  (MJ kg^-1DM)             8.5              9.0            8.8
Crude Protein (%DM)        9.1             13.5           12.0

Mean Bale Weight (kg)      383              430            390
No Bales Produced           57               75             45
Estimated total
  DM conserved (kg)        9169            14513          9126
Productivity
  tonnes DM ha^-1)         6.1              7.3            6.1
-----------------------------------------------------------------------
     Total fresh: 71.6 tonnes      Total  DM: 32.8 tonnes