The Israeli Dairy Cow
Economically Efficient and Environmentally Friendly
Israel Flamenbaum, Ph.D
State of Israel, Ministry of Agriculture, Extension service
The Israeli dairy cow is known for its high milk yield. This is especially commendable
achievement considering Israel's difficult environmental and climatic conditions. The annual
milk yield per cow for 2008, reached near 11,500 kg, up by nearly 2000 kg in the last
twenty years. The Israeli "production philosophy," strives to attain a high yield per cow,
considering the fact that the higher the yield per cow, the greater the production
efficiency, particularly in the feeding segment. This fact makes the Israeli production
concept economically viable (provided there is the capability to attain such yields, as
indeed is the case of Israel). Greater production efficiency in the feeding segment is
expressed by the smaller quantity of food and the smaller financial investment needed to
produce each liter of milk. This is largely attributed to the fact that the feeding costs for
cow body maintenance are virtually the same for cows of varying production levels, and
thus maintenance costs for the high-yield cow are spread over more liters. The figures
shown in Table 1 describe the efficiency of converting food into milk in cows of different
production levels (the data show the price per kg dry matter and the production cost per
liter milk for cows of different production levels, expressed as a percentage of a cow
producing 15 kg a day).
Table 1
Milk Yield
(kg/day)
15
20
25
30
35
40
45
50
Daily Food
Consumption
(kg dry matter, DM)
14.2
16.0
18.0
19.4
20.8
22.0
23.4
24.8
Price of Kg DM
(% of base level)
Production Cost of Kg Milk
(% of base level)
1.00
1.17
1.26
1.30
1.34
1.38
1.42
1.46
1.00
0.94
0.91
0.84
0.80
0.77
0.74
0.73
Table 1 clearly shows that although the cost of each kilogram of food, on a dry matter (DM)
basis, for cows yielding 35 kg per day (the average daily yield of a milked cow in Israel) is
35% higher than that for a cow yielding 15 kg per day, the production cost of each kilogram
milk in the Israeli cow amounts to 80% of that for low-yield cows and 90% of the milk
production cost for Western European cows.
Recently, other factors relating to milk production have grown in importance, among them,
the impact on the environment. In the future, dairy farms will be evaluated not only for
their economic efficiency, but also for their contribution to the production of greenhouse
gases and therefore their relative contribution to global warming. New data has come out
which show that also based on this index, the Israeli high-yield cow has a distinct edge over
its counterparts in other parts of the world. This advantage also has to do with the milk
production method in Israel and to the high production level attained by the Israeli cow.
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In an annual conference of the International Dairy Forum (IDF), held last year in Shanghai,
China, a special symposium dealt with the connection between agriculture in general and
the dairy industry in particular, and global warming. This article summarizes the main
points presented at the conference. Among other things, the article reviews the
characteristics of greenhouse gas production (primarily methane) by the milk cow and the
extent of this industry's contribution to global warming, while relating to the variance in
methane production among farm cows and to different production levels. The data
presented at the conference highlight the advantage of the Israeli cow and milk production
method over those in other parts of the world, and therefore should be brought to the
knowledge of the Israeli public.
Several gases, some of which are produced naturally and some emitted through human
activity, together constitute the greenhouse gases. Major greenhouse gases include carbon
dioxide (CO2), which contributes 50% of the greenhouse effect and is emitted mainly in the
combustion of fuel materials; methane (CH4) which contributes 20% of the effect and is
emitted primarily in the digestion processes and from ruminants' excrement; and nitrous
oxide (N2O), which contributes 5% of the effect and is discharged mainly in decomposition
processes of animal excrement when used as fertilizer in agriculture. The greenhouse
effect is created when these gases are emitted into the Earth's atmosphere, forming a layer
that prevents part of the solar energy reaching the Earth and reflected as heat energy
(infrared radiation) from returning to the atmosphere. This causes heating of the layer of
air enveloping the earth, a phenomenon defined today as global warming. Experts estimate
that, as a result of this process, the earth's temperature will rise 1.4°C by 2030, increasing
the frequency of extreme climatic events (2005, for example, was the hottest year on Earth
since temperature measurements first began at the start of the 19th century).
Greenhouse gases have a very long duration of stay in the atmosphere. Carbon dioxide, for
example, can "survive" in the atmosphere 100 years, methane – 10 years, and nitrous oxide
– 150 years. From here it follows that any emission of greenhouse gases joins the already
existing gases in the layer enveloping the Earth, thereby worsening the problem, reflected
by continued and increasing global warming.
A survey published at the beginning of the 90s determined that agriculture is the primary
contributor to greenhouse gas emission into the atmosphere – 35%. The energy sector
contributes 22%, households 13%, industry 18% and transportation some 10% of the overall
effect. It should be noted that different greenhouse gases have a different effect on global
warming. In general, this effect is measured in carbon dioxide equivalents, since it is the
main greenhouse gas. Methane gas's effect, for instance, is 21 times greater than that of
carbon dioxide, while nitrous oxide's effect is 310 times greater than carbon dioxide's.
Carbon dioxide is discharged, as aforesaid, in the wake of various combustion processes
(natural and man-made). The absorption of carbon dioxide by plants in the process of
photosynthesis offsets only part of this gas emission, so that the carbon dioxide balance is
negative, meaning that more carbon dioxide is emitted than absorbed, the result being its
increased concentration in the layer enveloping the Earth. Methane, as mentioned, is the
second most important greenhouse gas after carbon dioxide. The animal sector, particularly
ruminants, is the main contributor to the emission of methane. All told, animals contribute
nearly 40% of the overall methane gas emitted into the atmosphere, with ruminants
contributing about 25% of the total global production of methane. Deficient feeding is one
of the main contributors to increased methane emission by ruminants. An additional 16% of
methane gas is contributed by the processes of storage and handling of animal excrement,
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particularly of ruminants, with faulty handling in this segment likely not only to harm
groundwater, but to lead to a greater emission of methane gas into the atmosphere.
The dairy cattle sector contributes to the greenhouse effect through emission of the
following gases, listed in the order of their importance: methane, nitrous oxide, carbon
dioxide and gases emitted from cowshed cooling systems – CFC and HFC. Nearly 87% of the
methane gas contributed by the animal industries originates in food fermentation in
ruminants' stomachs, and a further 11% is contributed by their excretions. At any rate, it is
important to know that contrary to prevalent public opinion, the overall contribution of
greenhouse gases emitted by ruminants is no more than 3% of all the factors contributing to
global warming.
In ruminants, methane gas is produced naturally as a part of the fermentation process in
their abdomen. The eaten food remains in the cow's abdomen between 20 and 30 hours and
nearly 70% of it is digested there. The various food substances are degraded in the
abdomen to fatty acids (acetic acid, propionic acid and butyric acid), carbon dioxide (CO 2)
and hydrogen. The hydrogen in the food degradation processes occurring in the abdomen
are subsequently converted to methane (CH4). The scope of methane production in the
abdomen depends on the amount of time the food remains there. A portion based on
coarse, fiber-rich foods will remain in the abdomen longer, thereby increasing the amount
of methane gas produced in it. On the other hand, a portion based on concentrated foods,
mainly kernels, will remain a shorter time in the abdomen, thus leading to diminished
production of methane gas. Also the amount of food eaten, which is the direct outcome of
the cow's production level (multiples of maintenance) is associated with methane gas
production. Every 1 kg increase in the consumption of dry matter by the cow (enabled for
the most part by more concentrated portions) lowers the amount of methane it produces by
7.8%. From here it follows that the higher the production level and food consumption, the
lower the relative production of methane gas will be.
In the framework of the Shanghai symposium, data were presented showing the daily
methane gas production per cow and per kg milk produced, in cows with different
production levels. The data shown at the conference represent cows whose milk yield
ranges between 3400 and 6500 kg per annum. To evaluate these findings versus the
production levels of local cows, I assumed a linear rate of change in methane production in
relation to milk production. This means that there is a 5% increase in the daily methane gas
production per cow for every increase of 1000 kg in its annual milk production (the rate of
change obtained in the original data). Table 2 shows the daily methane gas production per
cow and per liter of produced milk, in cows with different milk production levels, among
them the Israeli cow producing 11,500 kg milk per year. (The data are expressed as a
percentage of the production of a cow with an annual yield of 3400 kg milk.)
Table 2.
Existing Data
Linear
Extrapolation
Production
Level
(kg/year)
3400
4500
5500
6500
7500
8500
9500
10500
11500
Methane
Production
(liter/day)
382
404
423
442
462
481
500
519
538
% of Base
100%
106%
111%
116%
121%
126%
131%
136%
141%
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Methane
Production
(liter/kg milk)
41.1
32.8
28.1
24.8
22.5
20.7
19.2
18.1
17.0
Change in
%
100%
80%
68%
60%
55%
50%
47%
44%
41%
If we accept the assumptions underlying the shown calculation, then methane gas
production for each kg milk produced under Israeli production conditions (yields of around
11,500 kg per cow per year), stands at 40% of that of the lowest-production cows (the New
Zealand cow) and 80% of that of Western European cows.
The conclusion drawn from the data shown in this article is that the Israeli cow and milk
production method prevailing in Israel are not only economically efficient but also more
environmentally friendly. If we have decided to continue consuming milk and if we wish to
do so with a minimum contribution to global warming, then it should be done by means of
the Israeli cow and the Israeli production method.
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