‫ عزمي ﺇبراهيم قطب هالل‬-4
‫تأثير عدد الخاليا الجسدية باللبن علي األداء التناسلي لماشية الفريزيان الحالبة‬
Azmy Ibrahim Kotb Helal
THE INFLUENCE OF SOMATIC CELL COUNT IN MILK ON REPRODUCTIVE PERFORMANCE
OF FRIESIAN DAIRY CATTLE
ABSTRACT
The objective of this study was to determine the effect of somatic cell count (SCC) in milk as They relate to stimate mastitis
type on culling, number service per conception, services period, days open, conception rate and calving interval in Friesian cows. A
total of 395 Friesian cows (108 of primiparous and 287 multiparous cows) having live body weight and ages ranged between 400 to
650 kg and 3 to12 years old, respectively, wese used in this study. At the beginning of experimental period, animals were randomly
divided into four groups according the SCC count in milk as they relate to stimate mastitis type. Cows in the 1st group having SCC
values <200000 cells/ml milk was considered as free mastitis (56 cows of primiparous and 169 cows of multiparous). While, cows in
the 2nd group having SCC from 200000 to 400000 cells /ml of milk considered as sub-clinical mastitis (18 cows of primiparous and
45 cows of multiparous). Cows in the 3rd group having SCC 400000 to 1000000 cells/ml in milk considered clinical mastitis (19 cows
of primiparous and 47 cows of multiparous) and cows in the 4th group were SCC >1000000 cells/ml in milk was chronic mastitis (15
cows of primiparous and 26 cows of multiparous). The effect of mastitis as They relate to SCC on number of percentage on culling
cows was significantly (P<0.01) increased in Chronic mastitis group (G4:24.39%) in compared with free (G1: 8.44%), sub-clinical
mastitis (G2,7.94%) and clinical mastitis (G3:13.39%). Days from calving to first service was significantly shorter (P<0.05) in free
mastitis cows groups (87.55 day) than that of sub-clinical, the clinical and chronic mastitis cows groups. Service period had not
affected by the parity. The Service period was significantly shorter (P<0.01) in free sub-clinical mastitis groups (19.65 and 43.5,
respectively) than that sub-clinical, clinical and chronic mastitis groups (43.5, 53.6 and 75.3 days, respectively). However the number
of services per conception (NS/C) significantly lower (P<0.01) in free mastitis group (1.65) than that of sub-clinical, clinical and chronic
mastitis groups (2.12, 2.16 and 3.10, respectively). whereas, it had not significantly affected by the parity. The number of days open
of Friesian dairy cows was significantly (P<0.05) affected by all groups of mastitis. While, they were not affected by the parity and
the interactions between groups and parities pregnancy period of Friesian dairy cows was not affected by mastitis groups, parity and
interaction between groups and parity. In addition, the calving interval of cows group in free mastitis group (385.25 d) were
significantly shorter (P<0.01) than the cows in sub-clinical, clinical and chronic mastitis group (443.65, 475.65 and 450.3 d,
respectively).
In conclusion:-sub-clinical, clinical and chronic mastitis affects reproductive performance resulting in an increase in the number
of days to first service, days open, and service per conception and increase culling rate as a result of reducing Pregnancy rate and
increase calving interval and consequently resulted in a poor reproductive performance and reduce milk production.