Cross breeding with the Boran Perhaps the greatest single factor influencing cattle production is reproductive rate." (M.B. Willis, Beef Cattle Production in Developing Countries - 1974) There are good reasons for the Boran being the breed of choice for the cow-component in two-way crossbreeding systems. Kenyan commercial ranchers have long recognised the Boran cow's prolific qualities and small size compared with other Zebu and composite breeds. Furthermore, by crossing with an appropriate Bos taurus sire, any desirable beef or dairy F1 combination can be custom-made. The genetic completeness of the Boran cow simplifies herd structure; making complicated three-way, terminal or rotational systems unnecessary. The two-way cross is flexible in the face of market demands - the type of sire can be changed according to the product needed. CARTWRIGHT (Journal of Animal Science, 30, p 706 - 711, 1970) summarizes all traits in beef cattle breeding in the table below: - TRAITS IMPORTANCE* COWS    BULLS   STEERS CONSISTANT HIGH FERTILITY + + 0 SMALL SIZE, LOW FEED, LAND COST / HEAD + 0 -- EARLY PUBERTY + 0 -- ABILITY TO CALVE EARLY + 0 0 ADAPTED TO THRIVE IN AREA + 0 0 LONG LIVED + 0 0 SOUND AND DOCILE + + + HIGH AVERAGE DAILY GAIN -- 0 + LEAN MUSCULAR CARCASS -HIGH CUT OUT 0 0 + TENDER, PALATABLE BEEF 0 0 + Importance* +  Desirable 0  Neutral or not of great     importance --  Undesirable TRAITS CLASSIFIED ACCORDING TO IMPORTANCE IN COWS, BULLS AND STEERS  Cross breeding for dual purpose Crossing the Boran with a dual-purpose breed such as Red Poll and Brown Swiss gives the option of breeding females for dairying and steers for fattening. Such crosses exhibit maximum hybrid vigour. “There is no doubt a great future for the Boran as a tropically adapted Zebu beef and milk production” -Bernard Irungu, Daily Nation, 3rd December, 1998  Cross breeding for beef production Model calculations carried out on field data collected on Kenyan ranches suggest the optimum crossbreeding system to be a two-way cross. A Bos taurus beef sire used in a commercial Boran cow herd. The F1 progeny exhibit maximum hybrid vigour and all F1 males go for beef production. F1 females may be used as breeders in other systems, or for beef. Replacements for the commercial herd come from purebreds maintained for the purpose. Dairy ranching is practiced in much of Africa - characterized by once-a-day milking of cows with calves at foot. Under these systems, it is desirable to maintain a proportion of Zebu blood to impart toughness to the herd. Crossing dairy breeds with the Boran produces excellent F1 hybrids with impressive milking qualities. However, a problem arises in maintaining a high level of heterosis in subsequent generations. Unless a source of F1’s is obtainable, criss-cross or rotational breeding will have to be used to retain a useful amount of hybrid vigour. Shown in the table below is a comparison of milk production between Holstein-Friesian X Boran (F1) and pure Holstein-Friesians in an extensive conventional dairying operation in east Kenya (rain-560 mm p.a.) BREED LACTATION NUMBER LACTATION IN KGS AVG      HIGH KG PER DAY AVG. LACTATION LENGTH (DAYS) NUMBER OF LACTATIONS F1 BORAN X HOLSTEIN- FRIESIAN 1 2494 4057 9.4 263 83 2 2741 4758 10.5 260 60 3 3017 5946 12.0 249 26               HOLSTEIN- FRIESIAN 1 3085 5339 11.0 275 173 2 3991 6043 13.7 284 137 3 4427 6319 15.3 290 97 The F1’s are milked alongside Holtein-Friesian in the same system. The shorter calving interval of the F1 cows is expressed in the shorter lactation lengths. The F1’s can be backcrossed to the Boran, or another terminal-sire, and the progeny sold as beef.  Cross breeding for milk production