PhD

A comparative evaluation of the feed conversion efficiencies of
crossbred Jersey and crossbred Brown Swiss Cattle of Kerala involving a
growth study and a lactation study using eight heifer calves and six milch
cows each for 28 and 14 fortnights respectively were carried out. While
records of daily feed intake, water consumption, fortnightly data on body
weight, body measurements and monthly data on haematological values were
maintained during the growth study, data on daily feed intake, milk yield,
fortnightly data on composition of milk, body weight and haematological
values were gathered during the lactation study. Digestion-cum-balance trials
were carried out during the 14th and 28th fortnights respectively under growth
study and during the 11th fortnight under lactation study.
There were no significant differences between crossbred Jersey and
crossbred Brown Swiss heifer calves in respect of their average daily dry
matter and water consumptions, various body measurements, haematological
values and digestion coefficients of various nutrients in their feed throughout
the experimental period of 28 fortnights except that the average digestion
coefficients of crude fibre in crossbred Brown Swiss heifer calves during
digestion trial I was significantly higher (P/0.01) than that of crossbred
Jersey. Both the groups of heifer calves did not differ significantly in respect
of their average daily consumptions of dry matter, gross energy, total
digestible nutrients, digestible energy, crude protein and digestible crude
protein per unit metabolic body size (W 0.75kg). The feed conversion
efficiency values as adjudged in terms of quantities of dry matter, gross
energy, total digestible nutrients, digestible energy, crude protein and
digestible crude protein needed per kg body weight gain in crossbed Jersey
were 13.70+1.01 kg, 54.25+3.13 Mcal, 8.09+0.46 kg, 36.32+2.09 Mcal,
1.83+0.10 kg and 1.10+0.06 kg respectively and the same were not
significantly different from the average values of 14.80 + 1.06 kg, 61.47 + 4.47
Mcal, 9.17 + 0.68 kg, 41.19 + 3.00 Mcal, 2.03 + 0.14 kg and 1.24 + 0.08 kg
respectively observed in the case of crossbred Brown Swiss heifer calves. Both
the groups did not differ significantly in respect of average daily nitrogen
retention of 18.48 + 0.61 and 18.06 + 1.02 g respectively during trial I and
17.90 + 1.02 and 18.86 + 1.15 g respectively during trial II.
Milch cows belonging to both the genetic groups of crossbred Jersey
and crossbred Brown Swiss not only maintained their body weight but also
showed an overall average fortnightly weight gain of 1.44 + 0.14 and 1.71 +
0.06 kg respectively without any significant difference between in respect of
feed consumption, digestion coefficients of nutrients and nitrogen retention,
the marginally positive nitrogen balance together with normal haematological
values obtained in respect of both the groups indicated that all the animals
and 6.43 kg respectively during the 1st, 7th and 13th fortnights in the case of
crossbred Jersey cows were not significantly different from those of 7.07, 7.08
and 6.80 kg respectively in the case of crossbred Brown Swiss cows. There
was no significant difference between cows belonging to the two genetic
groups in respect of their average daily consumption of DM, gross energy,
TDN, crude protein and DCP per unit metabolic body size. The overall
average consumptions of 5.76+0.23 Mcal, 0.76+0.03 kg, 3.17+0.13 Mcal and
103.45+4.60 g respectively of gross energy, total digestible nutrients, digestible
energy and DCP per kg of FCM produced by crossbred Jersey cows including
their maintenance requirements were not significantly different from
5.87+0.25 Mcal, 0.77+0.03 kg, 3.28+0.14 Mcal and 104.98+4.60 g respectively
of the same by crossbred Brown Swiss cows. The two crossbred groups of
milch cows failed to show any significant difference in respect of their
economic efficiency in terms of dairy merit as well as income over feed cost,
the average values being 22.74+0.88 and Rs.39.20 per day for crossbred
Jersey and 22.59+0.89 and Rs.39.12 per day for crossbred Brown Swiss cows
respectively.
No significant differences were observed in the performances of
crossbred Jersey and crossbred Brown Swiss cattle in respect of their growth
and milk production when reared in the same locality under identical
conditions of feeding and management.
FINDINGS :
An investigation involving a growth study and a lactation study was
carried out with a view to compare the feed conversion efficiencies of
crossbred Jersey and crossbred Brown Swiss cattle in respect of the two
production functions.
Growth study was carried out on eight heiger calves of 5-11 months of
age each belonging to the two genetic groups viz. crossbred Jersey and
crossbred Brown Swiss for a total period of 28 fortnights under identical
conditions of feeding and management. Individual records of daily intake of
feed and water, fortnightly data on body weight, monthly data on body
measurements and haematological values were maintained throughout the
period of experiment. Two digestion cum-balance-trials, one at the middle
and the other at the end of the experimental period were carried out to find
out the digestion coefficients of nutrients and efficiency of their utilization
from the feed. The feed conversion efficiency was assessed in terms of
efficiency of utilization of dry matter, gross energy, total digestible nutrients,
digestible energy, crude protein, digestible crude protein and nitrogen for
growth.
Lactation study was carried out on two groups of six lactating half bred
Jersey and half bred Brown Swiss cows each, of almost similar age, parity,
stage of lactation and level of production for a period of 13 fortnights under
identical conditions of feeding and management. Individual records of daily
feed intake and milk yield and fortnightly data on body weight,
haematological values and milk composition were maintained throughout the
period of study. The digestion-cum-balance trial was carried out during the
11th fortnight to find out the digestion coefficients of nutrients and efficiency
of nutrient utilization from the feed. The biological efficiency of utilization of
dry matter, gross energy, total digestible nutrients, digestible energy, crude
protein, digestible crude protein and nitrogen and the economic efficiency was
assessed in terms of income over feed cost as well as dairy merit.
From the overall results obtained the following inferences were drawn.
1.
Crossbred Jersey and crossbred Brown Swiss heifer calves showed an average
daily weight gain of 356.6 and 329.9 g respectively during the entire period of
28 fortnights, there being no significant difference between the two groups in
this respect.
2.
No statistically significant difference was observed between the two genetic
groups in respect of their body size as adjudged in terms of various body
measurements, viz. height at the bottom of the chest, top of withers and top of
rump; girth at the region of chest, paunch and flank and linear measurements
in terms of distance between pin bones, shoulder points, from point of
shoulder to the pin bones and from external angle of ileum to hip point.
3.
Crossbred Jersey and crossbred Brown Swiss heifer calves consumed on an
average 3.26+0.05 and 3.33+0.12 kg respectively of dry matter per day per
100 kg body weight during the entire period of 28 fortnights without showing
any significant difference between them in this respect.
4.
There was no significant difference between crossbred Jersey and crossbred
Brown Swiss heifer calves in respect of their average water consumption of
14.82 and 13.90 kg respectively per day.
5.
The haematological values in respect of both the groups showed no significant
difference and the values were within the reported normal range indicating
that all animals were in good nutritional status.
6.
The two genetic groups of heifer calves did not differ significantly in respect of
their ability to digest various nutrients in their ration except that during
digestion trial I, the average digestion coefficient of crude fibre was
significantly higher (P/0.10) in crossbred Brown Swiss (62.27+1.12) compared
to crossbred Jersey (55.68+1.28).
7.
The average consumptions of 108.08+0.84 g, 442.40+3.59 Kcal, 65.50+0.50 g,
295.37+2.37 Kcal, 14.86+0.14 g and 9.08+0.09 g respectively of dry matter,
gross energy, total digestible nutrients, digestible energy, crude protein and
DCP per W0.75 kg, obtained in the case of crossbred Jersey were not
significantly different from those of 107.19+2.24 g, 442.42+8.50 Kcal,
65.80+1.30 g, 295.52+5.71 Kcal, 14.72+0.27 g and 9.00+0.16 g respectively
obtained in the case of crossbred Brown Swiss heifer calves.
8.
The efficiency of utilization of feed for growth in terms of quantities of dry
matter, gross energy, total digestible nutrients, digestible energy, crude
protein and digestible crude protein needed per kg body weight gain in
crossbred Jersey viz. 13.70+1.01 kg, 54.25+3.13 Mcal, 8.09+0.4 kg, 36.32+2.09
Mcal, 1.83+0.10 kg and 1.10+0.06 kg respectively were not significantly
different from the average values of 14.80+1.06 kg 61.47+4.47 Mcal, 9.17+0.68
kg, 41.19+3.00 Mcal, 2.03+0.14 kg and 1.24+0.08 kg respectively in the case of
crossbred Brown Swiss heifer calves.
9.
There was no significant difference between crossbred Jersey and crossbred
Brown Swiss heifer calves in regard to their efficiency of utilization of dietary
protein for promoting growth as adjudged by nitrogen balance in g per day,
the average values being 18.48+0.61 and 18.06+1.02 g respectively in digestion
trial I and 17.90+1.02 and 18.86+1.15 g respectively in digestion trial II for the
two groups.
10. Milch cows belonging to both the genetic groups not only maintained their body
weight but also showed an overall average fortnightly weight gain of
1.44+0.14 and 1.71+0.06 kg respectively, there being no statistically significant
difference between them in this regard.
11. The haematological values obtained in respect of both the genetic groups were
within the reported normal range, suggesting that all experimental animals
were in good nutriture.
12. There was no significant difference between crossbred Jersey and crossbred
Brown Swiss cows in regard to the digestion coefficients of dry matter, crude
protein, ether extract, crude fibre and nitrogen free extract. Cows belonging
to both the genetic groups maintained a marginally positive nitrogen balance
without any significant difference in the mean values, indicating that all
animals were in good nutritional status.
13. The two groups of crossbred milch cows did not differ significantly in respect of
their feed consumption, the average daily intake of dry matter in kg per 100
kg body weight during the 1st, 7th and 13th fortnights being 3.92+0.22,
4.01+0.26 and 3.90+0.23 respectively in the case of crossbred Jersey and
3.90+0.29, 3.98+0.30 and 3.98+0.34 respectively in the case of crossbred
Brown Swiss cows.
14. The average daily milk yield of 7.28, 7.06 and 6.43 kg respectively obtained
during the 1st, 7th and 13th fortnights in the case of crossbred Jersey cows were
not significantly different from those of 7.07, 7.08 and 6.80 kg respectively in
the case of crossbred Brown Swiss cows.
15. The two groups of crossbred cows did not differ significantly in respect of their
milk composition throughout the experimental period of 13 fortnights except
during the 6th fortnight when the milk produced by crossbred Jersey had
significantly higher content of total solids and fat (P / 0.05) than that of
crossbred Brown Swiss cows.
16. Cows in the crossbred Jersey group did not differ significantly from those in
the crossbred Brown Swiss group in respect of their fortnightly yields of
butter fat, total milk solids, fat corrected milk and solids corrected milk.
17. The average daily consumptions of 158.13+8.17, 162.88+9.50 and 159.75+8.33 g
of DM and 19.98+1,16, 20.12+1.19 and 19.20+1.00 g of crude protein
respectively per W0.75kg during the 1st, 7th and 13th fortnights in the case of
crossbred Jersey were not significantly different from the average
consumptions of 157.58+9.86, 162.43+10.48 and 159.23+12.37 g of DM and
19.93+1.28, 20.17+1.33 and 19.12+1.67 g of crude protein respectively in the
case of crossbred Brown Swiss cows. Similarly the overall average daily
consumptions of 661.76+34.74 Kcal of gross energy 366.68+19.27 Kcal of
digestible energy and 11.91+0.65 g of DCP per W0.75kg in the case of
crossbred Jersey were not significantly different from the average
consumptions of 656.91+44.45 Kcal of gross energy, 368.10+24.68 Kcal of
digestible energy and 11.83+0.83 g of DCP respectively in the case of
crossbred Brown Swiss cows.
18. The efficiency of utilization of feed for milk production in terms of gross
energy, total digestible nutrients, digestible energy and digestible crude
protein needed for the production of one kg of FCM including the
maintenance requirements in the case of crossbred Jersey were not
significantly different from those values obtained in the case of crossbred
Brown Swiss cows, the overall averages being 5.76+0.23 Mcal, 0.76+0.03 kg,
3.17+0.13 Mcal and 103.45+4.60 g respectively for the former and 5.87+0.25
Mcal, 0.77+0.03 kg, 3.28+0.14 Mcal and 104.98+4.60 g respectively for the
latter. Similarly the average daily consumptions of 1.27+0.06, 1.35+0.05 and
1.50+0.12 kg of DM and 0.16+0.008, 0.166+0.006 and 0.181+0.015 kg of crude
protein respectively per kg of FCM produced, during the 1st, 7th and 13th
fortnights in the case of crossbred Jersey cows were not significantly different
from 1.41+0.07, 1.44+0.07 and 1.52+0.08 kg of DM and 0.178+0.009,
0.179+0.009 and 0.181+0.009 kg crude protein respectively in the case of
crossbred Brown Swiss cows.
19. The economic efficiency assessed in terms of income over feed cost and dairy
merit in respect of crossbred Jersey cows was not significantly different from
that of crossbred Brown Swiss cows, the average values being Rs.22.07 per
day and 22.74+0.88 respectively for the former and Rs.21.58 per day and
22.59+0.89 respectively for the latter.
The significance of the above inferences are discussed briefly.