Annals of the Academy of Romanian Scientists  
Series on Agriculture, Silviculture and Veterinary Medicine Sciences  
ISSN 2344-2085  
Volume 15, Number 1/2026  
179  
ZOOPASTORAL INDICES FOR EVALUATION  
AND CONVERSION OF PLANT PRODUCTION  
INTO ANIMAL PRODUCTION IN CATTLE DURING  
THE GRAZING SEASON  
Teodor MARUȘCA1  
Abstract. The paper includes several zoopastoral indices determined according to the  
climatic values and the floristic composition of the grassy carpet of permanent grasslands  
established in air temperature measurements and long-term animal experiments. The  
duration of the optimal grazing season is equal to the daily duration of the average air  
temperature between 10-20 0 C and decreases at altitude between 500-2,500 m with a  
gradient of 7.5 days / 100 m. The production of green mass (GM) evaluated based on the  
floristic survey of extensively used permanent grasslands is 0.2-31.5 t/ha and the pastoral  
value index (PV) is 0-100. The consumption of GM for one liter of cow's milk depending  
on PV is between 4-9 kg GM and for 1 kg of weight gain in young bulls is 50-100 kg GM.  
The total production per hectare of milk or weight gain is calculated by dividing the  
production of GM (kg/ha) by the average consumption of GM (kg) for 1 liter or 1 kg of  
animal product. By dividing the evaluated production of GM (kg/ha) by the daily  
requirement of GM / LU of 65 kg multiplied by the duration of the grazing season (days),  
the optimal loading per hectare is calculated.  
Keywords: zoopastoral indices, grazing season duration, milk production, weight gain,  
cattle  
DOI  
10.56082/annalsarsciagr.2026.1.179  
1. Introduction  
Determining livestock production during the grazing season is a very important  
operation for the pastoral economy.  
To establish milk production, live weight gain, wool, etc., rigorous, complicated  
and expensive experiments are required on an extremely wide diversity of  
grassland types from plains, hills to high mountains [10].  
Determining through experimentation the production of green mass and its  
quality, milk production or live weight gain in young animals on the dozens of  
types of grasslands used for grazing in Romania is almost impossible to achieve.  
1Eng., PhD. Teodor MARUȘCA, Research and Development Institute for Grasslands Brașov,  
Romania, Full Member of The Academy of Romanian Scientists, (e-mail: maruscat@yahoo.com).  
 
180  
Teodor Marușca  
Zoopastoral indices established in experiments with animals on pastures in  
different seasonal and grassland vegetation conditions were used.  
The paper presents the main zoopastoral indices that refer to the duration of the  
grazing season depending on altitude, average air temperature and precipitation,  
the evaluation of green mass production and its quality, the optimal animal load  
per hectare, the feed-animal product conversion per hectare and their economic  
value.  
2. Material and methods  
Main zoopastoral indicator was the optimal duration of the grazing season for  
which the average daily temperatures of 5, 10, 15 and 20 degrees per altitude and  
the average decadal precipitation from the work Clima României [16] were taken  
into analysis.  
Using altitudinal gradients of temperature and precipitation between 100-500 m  
and 500-2,500 m, the optimal duration of the grazing season was evaluated [6].  
The production of green fodder mass and pastoral value were determined using a  
new method based on the floristic survey of grasslands with indices of their  
fodder value [1, 2, 3, 7, 13] and green mass [9].  
Following this method, the plant productivity of numerous photo-sociological  
associations and alliances, types and habitats of grasslands, also published in the  
present Annals of the AOŞ-R, was evaluated.  
In order to evaluate livestock production per hectare during the grazing season, it  
was necessary to establish feed-to-milk and feed-to-liveweight conversion indices  
based on rigorous experimentation with animals in different seasonal conditions  
and types of grasslands.  
For milk production, the long-term experience with cows from Blana-Bucegi [8]  
and from Măgurele-Brașov [15] was taken into account.  
For the conversion indices into live weight gain, namely the amount of feed per 1  
kg gain, numerous experiments with young female breeding bulls carried out in  
Vlădeni (1972-72), Măgurele-Brașov (1974-77; 1980-82), Sighet-MM (1981-83)  
and others were taken into analysis [5].  
On sown grasslands of high forage value in these experiments with animals  
fertilized at an average level of 200 kg/ha N; 23 kg/ha P2O5 and 44 kg/ha K2O,  
8.49 t/ha dry matter (DM), 1,740 kg/ha crude protein (CP) were obtained, which  
ensured 810 kg/ha live weight gain in young cattle with a consumption of 10.48  
kg DM/ 1 kg weight gain [5].  
Contributions to the Assessment of the Productivity of Natura 2000 Grassland Habitats  
in the Transylvanian Plain Continental Bioregion  
181  
Transforming SU production into green mass (GM) by multiplying by the  
coefficient 5 results in 52.4 kg GMS for 1 kg of weight gain [14].  
These experiments were carried out on temporary (sown) grasslands after the  
restoration of the degraded Nardus stricta grassland at Vlădeni and Sighetul  
Marmației (Agriș) or on arable land at Măgurele-Brașov and Sighetul Marmației  
(Stațiune) [5].  
At Vlădeni-BV [4] and Agriș-MM [12], conversion into live weight gain in young  
cattle was established and in the case of improving degraded grasslands, only  
through fertilization with chemical fertilizers.  
On these permanent grasslands with spontaneous flora vegetation, at Agriș-MM  
7.92 t/ha SU was obtained and in animals 340 kg/ha live weight gain with 23.3 kg  
SU/1 kg gain and at Vlădeni-BV the average consumption was 11.20 kg SU/kg  
gain, resulting in an average of 17.25 kg SU/kg gain, respectively 86 kg GM/kg  
gain, under conditions of proper fertilization and use.  
3. Results and discussions  
First zoopastoral indicator was the duration of the optimal grazing season  
0
depending on the duration of the average air temperature between 10 C and  
20 0C, existing between 100-500 m altitude in the plain and hilly area and above  
500 m in the mountainous area (Table 1).  
Table 1. Optimal period for grazing animals in grasslands [6, 11]  
Duration  
Optimal duration (days)  
Ensured  
Altitude  
difference  
Normal climate  
Adt ≥ 10 0C (days)  
Adt ≥ 20 0C (days)  
humidity  
conditions  
25  
conditions  
2,500  
25  
40  
0
0
25  
2,200 – 2,400  
2,000 – 2,200  
1,800 – 2,000  
1,600 – 1,800  
1,400 – 1,600  
1,200 – 1,400  
1,000 – 1,200  
800 – 1,000  
600 - 800  
40  
40  
55  
70  
85  
0
0
0
0
0
0
0
0
55  
70  
85  
100  
115  
130  
145  
160  
175  
55  
70  
85  
100  
115  
130  
145  
160  
100  
115  
130  
145  
160  
175  
190  
205  
400 - 600  
200 – 400  
0 – 200  
0
45  
90  
175  
190  
205  
145  
115  
+ 15 days  
(0 - 500m)  
- 7.5 days  
(500 – 2,500m)  
Gradients for  
100 m alt.  
- 7.5 days  
(0 – 2,500m)  
- 22.5 days  
(0 - 500m)  
- 7.5 days  
(0 – 2,500m)  
182  
Teodor Marușca  
From these data it results that the duration of the grazing season between 100-500  
m altitude increases with a gradient of 15 days / 100 m (115-175 days) after which  
between 500-2,500 m alt. it decreases by 7.5 days / 100 m (175-25 days).  
The calculation formulas were as follows:  
G.s.d (100-500 m alt.) = 100 x 0.15 x Alt.  
in which:  
G.s.d = duration of grazing season (days)  
Alt. = altitude (m)  
G.s.d (500-2,500 m alt.) =212 – 0.075 x Alt.  
The determination of green mass production and pastoral value of a permanent  
grassland exploited by animal grazing was based on floristic surveys [9].  
The evaluation of green fodder production was done according to the formulas:  
GMI= 4 x P(%) ind. 4...+ 9 x P(%) ind. 9/100  
in which:  
GMI = average green forage mass index  
P (%) = species participation in the grassy carpet  
Ind. 4....9 = mass assessment notes for fodder species  
The list of species mass assessment notes is very long, it is presented in widely  
circulated works [9].  
The average green mass index (IGM) is multiplied by a coefficient of  
transformation into green mass production (t/ha) (Table 2).  
The pastoral value (PV) of a permanent grassland is determined by the formula:  
PV = Σ P (%) x F / 9  
in which:  
P (%) = participation of the forage species in the grassy carpet  
F = feed quality index, with the notations:  
1 = toxic to animals and humans;  
2 = harmful to animal products;  
3 = harmful to the grass carpet;  
4 = poor forage (ballast);  
5 = mediocre forage (formerly F1);  
Contributions to the Assessment of the Productivity of Natura 2000 Grassland Habitats  
in the Transylvanian Plain Continental Bioregion  
183  
6 = medium fodder (formerly F2);  
7 = good fodder (formerly F3);  
8 = very good fodder (formerly F4);  
9 = excellent forage (formerly F5);  
X = species with unknown forage value.  
Similarly, indices of forage quality of species in the grassy carpet of a grassland,  
due to lack of space, are presented in other previous works [9].  
After calculations, the PV of a grassland is estimated as follows:  
0-5 severely degraded  
5-15 very weak  
15-25 weak  
25-40 mediocre  
40-60 medium  
60-80 good  
80-100 very good  
Table 2. Production indices for forage species and estimation of useful production per hectare of  
unfertilized permanent grassland [9]  
Average green mass  
production indices for  
forage species (M)  
0.1 – 0.5  
Transformation  
coefficients in green  
mass production (GM)  
Estimated green mass  
production (GM)  
(t/ha)  
Production value  
appreciation  
x 1.8  
x 1.9  
x2.0  
0.2 – 0.9  
1.0 – 1.9  
2.0 – 3.0  
3.2 – 4.2  
Very Low  
Low  
0.5 – 1.0  
1.0 – 1.5  
1.5 – 2.0  
x2.1  
2.0 – 2.5  
2.5 – 3.0  
3.0 – 3.5  
3.5 – 4.0  
4.0 – 4.5  
4.5 – 5.0  
5.0 – 5.5  
5.5 – 6.0  
6.0 – 6.5  
6.5 – 7.0  
7.0 – 7.5  
7.5 – 8.0  
8.0 – 8.5  
8.5 – 9.0  
x 2.2  
x 2.3  
x 2.4  
x 2.5  
x 2.6  
x 2.7  
x 2.8  
x 2.9  
x3.0  
4.4 – 5.5  
5.8 – 6.9  
7.2 – 8.4  
Low-Medium  
Medium  
8.8 – 10.0  
10.4 – 11.7  
12.2 – 13.5  
14.0 – 15.4  
16.0 – 17.4  
18.0 – 19.5  
20.2 – 21.7  
22.4 – 24.0  
24.8 – 26.4  
27.2 – 28.9  
29.8 – 31.5  
Medium-Good  
Good  
Good-Very good  
Very good  
Excellent  
x3.1  
x 3.2  
x 3.3  
x 3.4  
x 3.5  
184  
Teodor Marușca  
The optimal loading and grazing capacity of a pasture is determined by the  
formula:  
GC (LU/ha) = GM Production (kg/ha) / G.s.d x 65  
GC = grazing capacity (animal load)  
LU = large cattle unit  
GM = green fodder mass  
G.s.d = grazing season duration  
65 = amount of GM (kg) required for 1 LU/day (50 kg+30% annual and seasonal  
fluctuations of GM)  
Another calculation formula for evaluating grazing capacity (CP) is:  
GC = PV x C (LU/ha)  
where ˶ C ̋ is an altitude-varying capacity coefficient. (Table 3).  
Table 3. Grazing capacity coefficient value (C)  
Altitude (m)  
Grazing season (days)  
Coefficient (C) for pastures  
Medium level  
fertilization  
Unfertilized  
2,200-2,400  
2,000-2,200  
1,800-2,000  
1,600-1,800  
1,400-1,600  
1,200 -1,400  
1,000-1,200  
800-1,000  
600-800  
400-600  
200-400  
0-200  
40  
55  
70  
0.010  
0.014  
0.018  
0.022  
0.026  
0.030  
0.034  
0.038  
0.042  
0.046  
0.050  
0.054  
-
-
-
85  
0.052  
0.058  
0.064  
0.070  
0.076  
0.082  
0.088  
0.094  
0.100  
100  
115  
130  
145  
160  
175  
190 *  
205 *  
Gradients  
for 100 m altitude  
-7.5 days  
- 0.002  
- 0.003  
*) in river grasslands and irrigation conditions  
Of particular importance are the conversion coefficients of green mass production  
into animal production, which are based on consumption indices for 1 liter of milk  
or 1 kg of live weight gain in cattle.  
The green fodder consumption index for 1 liter (L) of milk was calculated using  
the formula:  
Contributions to the Assessment of the Productivity of Natura 2000 Grassland Habitats  
in the Transylvanian Plain Continental Bioregion  
185  
GM consumption (kg) for 1 L milk = 9.5 – 0.05 x PV  
in which:  
GM (kg) = green fodder mass  
PV (ind.) = pastoral value  
This GM consumption for 1 liter of milk varies between 9 kg GM for those with  
very low PV to 4 kg GM for a PV index of 100.  
Cow milk production per hectare was calculated using the formula:  
Milk production (L/ha) = GM (kg/ha) / GM consumption (kg) for 1 L  
In the case of intensive fertilization and use of grasslands, the formula will apply:  
Milk production (L/ha) = Milk production (L/ha) = PV x Dsp x 0.6 [8]  
in which:  
PV= pastoral value index  
Dsp = duration of grazing season (days)  
0.6= feed-to-milk conversion coefficient determined in long-term experiments  
with cows in the pasture  
The GM consumption index (kg) for 1 kg of live weight gain in young cattle was  
calculated according to the formula:  
GM consumption (kg) for 1kg gain = 100 – 0.5 x PV  
Similarly, the consumption of GM for 1 kg of live weight gain varies between 50  
kg GM for the maximum PV index of 100 to 100 kg GM for the lowest PV index.  
The production of growth (meat) in young cattle per hectare is calculated  
according to the formula:  
Crop production (kg/ha) = GM (kg/ha) / GM consumption (kg) for 1 kg crop  
After these calculations, depending on the category of cattle existing in the  
grazing season, dairy cows or young cattle, the economic value of a pasture can be  
assessed by multiplying milk production by 0.5 €/Liter and weight gain by 3.2  
186  
Teodor Marușca  
€/kg, final indicators necessary for calculating the economic efficiency of raising  
these animals [MADR 2026].  
Conclusions  
(1). Climatic data (air temperature, precipitation regime), floristic surveys of the  
grassy carpet and long-term experimental results with animals during the grazing  
season can be taken into account for establishing zoopastoral indices.  
(2). Zoopastoral indices are very important for establishing the optimal duration of  
the grazing season, grazing capacity, green mass consumption for 1 liter of cow's  
milk or 1 kg of live weight gain in young cattle, livestock production per hectare  
and other economic data.  
(3). The duration of the grazing season increases between 100-500 m alt. (115-175  
days) by 15 days / 100 m altitude and decreases at 500-2,500 (175-25 days) with a  
gradient of 7.5 days / 100 m altitude.  
(4). The average consumption of GM for 1 liter of milk is between 4-9 kg GM and  
that for 1 kg of live weight gain between 50-100 kg GM depending on the value  
of the PV index.  
(5). The final production of milk with a cost at European level of 0.5 Euro / kg  
and that of live weight gain of 3.2 Euro / 1 kg more accurately expresses the  
economic value of a permanent pasture.  
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