Con este artículo se trata de resaltar aspectos zootécnicos y económicos de la raza Sanmartinera y su utilización en forma racional y sostenible, como fuente genética para el desarrollo eficiente de la ganadería Orinoquense.

Se describen sus cualidades y aptitudes productivas, como raza pura y en cruces con Cebú (Brahman), Santa Gertrudis y Charoláis; igualmente, los resultados comparativos de peso presacrificio y rendimiento en canal de cruces F ½ SM x ½ Cebú y Cebú puro.

The Muzaffarnagari is the largest and heaviest sheep breed of India. It is well adapted to the hot humid irrigated regions. This breed is generally found in the Muzaffarnagari, Bulandshahr, Saharanpur, Meerut, Bijnor and Dehradun districts of Uttar Pradesh and in some parts of Delhi and Haryana. The fast body growth coupled with high feed conversion efficiency are the main characteristics of this breed. The animals are medium to large in size, having slight convex face lines. The coat is generally white and dense but relatively coarse and the head is large with long and drooping ears. Both male and females are polled. The tail is very long and extends to the fetlock joint. The average body weights at birth, 3, 6, 9 and 12 months of age were 3.49±0.04, 15±0.20, 26.5±3.56, 30.4&0.40 and 33.4±0.46 kg, respectively.

When the Spaniards discovered and conquered the Canary Islands in the 15th Century, they found a type of hair sheep, a breed described by the colonists as “white in colour, large in size and with horns in the males”. This discovery provokes the question: from where did these sheep originate? All other breeds of wool-less sheep in the world in that period were located in the sub-Saharan regions, far away from the Canary Islands and with no possible connection.

Archaeologists claim that Northwest Africa was populated by wool sheep from 4000–3000 BC. Northwest Africa is the nearest geographical point of the African continent to the Canary Archipelago. It was also there that the native pre-Hispanic human population is thought to have originated. Did the wool-less sheep breed arrive with these people? The answer is probably yes. It is likely that the population of hair sheep arrived between 3000–2000 BC in a northern expansion of these animals, accompanying the first inhabitants of the islands.

After the Spanish conquest, the Canary Islands provided a necessary stop for the explorers of the New World. Various testimonies exist describing the arrival of the first sheep to the Caribbean Islands. This process of animal introduction started with Columbus′ second voyage, after which domestic animals formed a usual part of the shipment arrangements. This raises a third question: what role did the Canary Island sheep play in the origin and evolution of the present Caribbean and Latin-American hair breeds? The majority of researchers working with these animals in America and the Caribbean think that the origin of their wool-less sheep breeds is related to the traffic of black slaves during the 17th and 18th centuries. It may be claimed that this influence of sub-Saharan animals exists as an additional influence of other wool-less sheep breeds, which arrived in the Caribbean from the Canary Islands two centuries earlier. Today, the ancient native hair sheep breed is extinct in the Canary Islands although some wool-less sheep have recently been introduced from Venezuela.

All these questions and ideas are investigated in this paper, through historical references and current research.

Marwari is a desert goat breed of India and is found in the western part of the country. It is well known for its tolerance of hot and cold climates, disease resistance and thriving in very harsh nutritional conditions. It is a hairy black coloured goat. The means of the body length, body weight and ear length were estimated as 54 cm, 83 cm and 20 cm in males and 49 cm, 72 cm and 16 cm in females. Males have larger and stronger horns than females. The average adult body weight in males and females is 46 and 30 kg, respectively. The overall milk yield at 200 days is 98 kg. The kidding percentage in field conditions is 79.3 percent and multiple birth is about 19 percent. The Marwari is an early maturing breed as the average age of puberty is 306 days. The mortality in kid is 3.3 percent and in adults 3.5 percent in field conditions. The marketing and production economics of goats in its home tract have been analysed to ascertain viability of goat enterprise. The breed improvement programme was started in 1990–91 in its home tract involving farmers' flocks.

Characterization of three strains of indigenous goats found in three regions of Tanzania was undertaken on the basis of their phenotypes viz: body weight and measurements, colour pattern, ears and horns.

The three strains differed in the body weights and in the frequencies of the different coat colours. The Dodoma and Mtwara strains had similar body measurements, whereas the Kigoma strain was significantly smaller.

Mehsana buffalo is distributed in Mehsana, Banaskantha and Sabarkantha districts of North Gujarat in India. The animals are reared for milk production. The management practices in the breeding tract were studied. The physical, production and reproductive characters were recorded. The Dudhsagar Research and Development Association located in Mehsana district has undertaken breed improvement programmes in farmers'herds by running field progeny testing and providing other animal husbandry services like artificial insemination, health coverage, etc. This has resultedin the improvement in the reproductive performance as is evident from the decreasein the average first service period by 74 days and the average first calving interval by 103 days from 1989 to 1997. Microsatellite DNA marker analysis was carried out on 25 Mehsana buffalo DNA samples using seven markers for genetic characterization of the breed. Number of alleles at different loci ranged from four to seven and heterozygosity ranged from 0.40 to 0.92.

En este documento se presenta una red temática latinoamericana con financiación del Programa Iberoamericano de Ciencia y Tecnología para el Desarrollo (CYTED), dedicada a la conservación de los recursos genéticos de los animales domésticos, al estudio de los sistemas de explotación tradicionales, as í como las repercusiones sociales y ecológicas de estos recursos, además de la evaluación de sus posibilidades en el desarrollo rural sostenible de los países implicados.

En esta red participan mas de 140 investigadores de 16 equipos multidisciplinares ubicados en 9 países Latinoamericanos (México, Brasil, Bolivia, Argentina, Venezuela, Uruguay, Cuba, Portugal y España).

Se presentan los objetivos de la red y las actividades realizadas junto con las acciones planeadas para el futuro.