AN INVESTiGTiON OF BASIC MilK COMPOSITION OF GOlPAYGANIAN CATTLE.
1999
Koohi Habibi , Mahvash | Ghorbani , Gholam Reza | Gol Mohammadi, Heidar Ali
Milk yield and milk compositions are not generally constant and many factors influence them. In order to study the factors in Golpayegan region, 1100 heads of cross-bred dairy cows (with different breed composition of Golpayegani, Brown Swiss and Holshtein breed), belonging to 220 farmers (small holders), in 35 villages were randomely chosen" according to Participatory Action Research. The required information were recorded individually for them with- specified the ear tags. For four years and during the years of 1994-1997,-monthly, milk samples were taken for cows for determination' of fat, protein, lactose, solid non-fat (SNF), and total solid content. At the time of milk sampling, milk yield, date of drying, date of calving, number of lactations, body weight and Information of nutrition were also recorded. The result showed mean of 2918.44 kg. for least squre for a lactation period. Mean of fat, protein, lactose, SNF, and total solids were 122.4, 116.7, 160.5, 291.9 and 411.5 kg., \\ respectively. The mean of fat, protein, lactose, SNF, and total solids percent were 4.2, 4.03, 5.5, 10, and 14.1 percent, respectively. Effects of genetic group, number of lactation, management, nutrition, year, and season all were significant on milk production and milk composition (PO.OI). Year was very effective on percent of milk componenets (PO.Ol). Season was effective on fat, protein, SNF, and total solid percentages (PO.Ol). Gegetic groups (upgrading) was effective on fat percent and total solid content (PO.Ol). Effect of feeding levels also, was significant on SNF percent and total solid content of milk (PO.05). It can be concluded that in the , region, increase of exogenous gene improved average milk yield, however decreased quality of milk components specially, milk fat percent and total solid content. Feeding managenent also improved SNF percent and total solid content.
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