الفهرس 
Material and methodsOnly 14 pages are availabe for public view
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Abstract
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6. SUMMARY
Milk production records for Egyptian buffalo cows raised in
Mehallet Moussa farm. Animal Production Research Institute. Ministry
of Agriculture. Egypt were collected in the period from
1970 to 1985. Data on 2946 lactation records including 430 buffalo
cows (Paternal half-sister) representing 51 sires were used
to estimate the genetic and phenotypic variations of some productive
and reproductive traits. Measures of production were lactation
period (LP) and yield of milk recorded on 90-day (90DY).
180-daY (180DY). 305-day (305DY) and total lactation (TY). Reproductive
measures were age at first calving (AFC). birth weight of
calf (BW). number of services per conception (NSC). calving to
first service interval (CFS). insemination period (IP). days open
(DO). gestation length (GL) and calving interval (el>. Estimation
of repeatability and heritability for these traits was estimated
by mixed model analysis. The results obtained could be summarized
as:
(1) Productive trAits:
Averages of 90DY. l80DY. 305DY. TY and LP were 601. 994.
1352.6. 1552.6 Kg and 281 days respectively. Parity effects were
highly significant (P(O.OOl) for all milk yield traits. All productive
traits increased with parity order till reaching the peak
and declined thereafter. except TY and LP increased linearly as
order of lactation advanced. Season of calving affected (P(O.OOl)
all productive traits except 90DY. Summer calvers had the highest
production of 90DY. 180DY and 305DY. but spring-calvers had the
highest TY and LP. Year of calving constituted highly significant
(P(O.OOl) source of variation for all productive traits studied.
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All milk yield traits decreased curvlinearly as age at calving
advanced except TY which decreased linearly. Age at calving was
found to have significant (p<O.05 or P<O.OOl) effects on all productive
traits.
For all lactations. sire of the cow affected significantly
(P<O.05 or P<O.OOl) all productive traits studied while for
first lactation there was a significant sire effects (P<0.05) for
305DY and LP. However. cow within sire affected significantlY
(P<O.OOl) productive traits in all lactations. Repeatability
estimates were moderate and ranged from 0.295 to 0.407 for all
lactation traits studied. Heritability estimates for all productive
traits in the first and across all lactations were low and
ranged between 0.006 to 0.109.
(II) Reproductive traits:
Averages of AFC. BW. NSC. CFS. IP. DO. GL and CI were 38.0
month. 35.0 Kg. 1.4. 165.7 day. 36.9 day. 202.7 day. 313.6 day
and 500.3 day. Most reproductive traits decreased linearly as
parity advanced (e.g. CFS. IP. NSC and DO). Parity had significant
(P<O.OOl) effects on CFS. IP. NSC. DO and CI. Season of calving
affected significantly (P<O.05 or p<O.OOl) CFS. DO. GL and
CI. Winter and spring calvers had shorter CFS. DO and fewer NSC
and longer CI compared to other seasons. Differences between year
of calving were highly significant (P<O.OOl) for CFS. IP. NSC. DO
and BW. All reproductive traits studied decreased in a curvilinear
manner as age of cow advanced and the differences were significant
(P(O.OOl) for most traits.
Sire of th~ cow did not affect all reproductive traits of
first lactation (except CFS) and across all lactations (except
~---_.- -
- 12.’-
aWl. Differences in all reproductive traits due to effects of cow
within sire were significant. Estimates of repeatability were low
for CFS. IP. NSC. DO. GL (estimates ranged from 0.01 to 0.05) or
moderate for BW and CI (0.32. 0.24. respectively). Estimates of
heritability for most reproductive traits were low and ranged
between 0.0 to 0.25.
-1.21-
6. SUMMARY
Milk production records for Egyptian buffalo
Mehallet Moussa farm. Animal Production Research
cows raised in
Institute. Ministry
of Agriculture. Egypt were collected in
1970 to 1985. Data on 2946 lactation records
the period from
including 430 buffalo
cows (Paternal half-sister) representing 51
to estimate the genetic and phenotypic variations
sires were used
of some producti
ve and reproductive traits. Measures of production were lactation
period (LP) and yield of milk recorded on 90-day (90DY).
180-daY (180DY). 305-day (305DY) and total lactation (TY) Reproductive
measures were age at first calving (AFC). birth weight of
calf (BW). number of services per conception (NSC). calving to
first service interval (CFS). insemination period (IP). days open
(DO). gestation length (GL) and calving interval (el>. Estimation
of repeatability and heritability for these traits was estimated
by mixed model analysis. The results obtained could be summarized
as:
(1) Productjve trAits:
Averages of 90DY. 180DY. 305DY. TY and LP were 601. 994.
1352.6. 1552.6 Kg and 281 days respectively. Parity effects were
highly significant (P (0.001) for all milk yield traits. All producti
ve traits increased with parity order till reaching the peak
and declined thereafter. except TY and LP increased linearly as
order of lactation advanced. Season of calving affected (P (0.001)
all productive traits except 90DY. Summer calvers had the highest
production of 90DY. 180DY and 305DY. but spring-calvers had the
highest TY and LP. Year of calving constituted highly significant
(P (0.001) source of variation for all productive traits studied.
-i26-
All milk yield trai ts decreased curvlinearly as age at calving
advanced except TY which
found to have significant
decreased linearly. Age at
(p<0.05 or P<O.OOl) effects
calving was
on all producti
ve traits.
For all lactations. sire of the cow
productive
affected significantly
(P<0.05 or P<O.OOl) all trai ts studied while for
first lactation there was a significant sire effects (P<O.05) for
305DY and
(P<O.OOl)
LP. However. cow within sire affected significantlY
productive traits in all lactations. Repeatability
from 0.295 to 0.407 for all
estimates for all producall
lactations were low and
estimates were moderate and ranged
studied. Heritability
the first and across
lactation traits
tive traits in
ranged between 0.006 to 0.109.
(II) Re~roductive traits:
Averages of AFC. BW. NSC. CFS. IP. DO. GL and CI were 38.0
month. 35.0 Kg. 1.4.165.7 day. 36.9 day. 202.7 day. 313.6 day
and 500.3 day. Most reproductive traits decreased linearly as
parity advanced (e.g. CFS. IP. NSC and DO). Parity had significant
(P<O.001) effects on CFS. IP. NSC. DOand CI. Season of calving
affected significantly (P<O.05 or p<O.001) CFS. DO. GL and
CI. Winter and spring cal vers had shorter CFS. DOand fewer NSC
and longer CI compared to other seasons. Differences between year
of calving were highly significant (P<O.001) for CFS. IP. NSC. DO
and BW. All reproductive traits studied decreased in a curvilinear
manner as age of cow advanced and the differences were significant
(P (0.001) for most traits.
Sire of th~ cow did not affect all reproductive traits of
first lactation (except CFS) and across all lactations (except
- 12.’-
aWl. Differences in all reproductive traits due to effects of cow
within sire were significant. Estimates of repeatability were low
for CFS. IP. NSC. DO. GL (estimates ranged from 0.01 to 0.05) or
moderate for BW and CI (0.32. 0.24 . respectively) Estimates of
heritability for most reproductive traits were low and ranged
between 0.0 to 0.25.