Data from the Butana herd of Atbara Livestock Research Station were analyzed for the period 1949 -1999. The least squares means for age at first calving, calving interval, milk yield per lactation, daily milk yield, lactation length and dry period were 45.05 ± 3.56 months, 382.38 ± 8.30 days, 1662.57 ± 108.96 kg, 6.10 ± 0.40 kg, 268.17 ± 5.56 days and 119.10 ± 8.30 days, respectively. The analysis of variance revealed that the sire and parity number influenced the studied traits, while year-season of calving influenced the milk yield per lactation, daily milk yield and lactation length. Linear and quadratic regressions on lactation length significantly influenced milk yield per lactation and daily milk yield. Heritability estimates for age at first calving, calving interval, milk yield per lactation, daily milk yield, lactation length and dry period were 0.19 ± 0.07, 0.09 ± 0.03, 0.26 ± 0.06, 0.27 ± 0.07, 0.04 ± 0.02, and 0.09 ± 0.03, respectively. This study highlighted the importance of conserving the indigenous dairy cattle breeds for future generations. The presence of significant variation and the corresponding heritability estimates give promise of reasonable genetic improvement under selective breeding with respect to milk yield characters.

Abstract. The data obtained from the dairy herd of the Arab Company for Agricultural Production and Processing (ACAPP) in a semi arid area 40 km south of Khartoum involved 337 cows with a total of 1049 records from 16 years between 1986 and 2002. The least squares means for age at first calving, calving interval, days open, lactation milk yield, daily milk yield, lactation length and dry period were 29.76±0.40 months, 433.12 ± 6.70 days, 167.79±7.08 days, 3475.53±78.89 kg, 12.29±0.28 kg, 294.10±3.62 days and 164.08 ± 6.70 days, respectively. The analysis of variance showed that the parity number had significant (p<0.05) influences on all studied traits, while year-season of calving influenced (p<0.05) age at first calving, milk yield per lactation and daily milk yield. The sire of cow influenced (p<0.05) lactation yield, daily yield, lactation length and days open. The effects of linear and quadratic regressions of both lactation yield and daily yield on length of lactation were also highly significant (p<0.01). Heritability estimates of age at first calving, calving interval, milk yield per lactation, daily milk yield, lactation length and dry period were generally low (0.098±0.104, 0.047±0.046, 0.130±0.042, 0.123±0.041, 0.172±0.062 and 0.044±0.031, respectively) except the heritability of days open which was 0.51±0.37. The productivity of the herd in this study which averaged 12.3 kg/cow/day was much lower than the expected productivity of Holstein Friesian cows, which reflects the negative impact of the prevalent environment in the Sudan. More records and economic data are required to examine the economic feasibility of raising pure Friesians under Sudan conditions.

Data from Zebu x Friesian crossbred dairy cows of different upgrading kept in the Kenana Sugar Company (KSC) farm, 300 km south of Khartoum on the bank of the White Nile in the low rainfall savannah region were collected over a period from 1984 to 2004 and analyzed using Harvey's (1990) Least Squares programme. The results indicated that there were no significant differences in milk yield per lactation, daily milk yield and lactation between the 25% and 37.5% genetic groups. The 50% Zebu x Friesian group produced significantly more milk per lactation (2721.10 ± 87.36 kg) compared to the 25% and 37.5% groups (2067.20 ± 241.62 and 2192.68 ± 122.66, respectively). The milk yield per lactation and daily milk yield of the 50, 62.5, 75 and 87.5% breed groups was not significantly different. There were no significant differences in length of lactation between the 25%, 37.5% and the 50% group (267.99±18.14, 273.11±9.25 and 278.75±6.52, respectively). Groups with 75% and 87.5% of Friesian blood proportion had significantly longer lactation days (305.09 ±10.63 and 347.07 ±30.14, respectively). The range for dry period was between 78.37±12.27 days for the 75% genetic group to 92.56±16.76 days for the 25% group. The mean calving intervals for the five genetic groups ranged from 367.85±21.38 days for the 75% group to 394.60±16.33 days for the 50% group. The earliest age at calving (41.56±2.16 months) was achieved by the 37.5% group while the latest age at first calving (49.01±1.29 months) was recorded for the 62.5 % group. The results of this study and other similar studies in tropical countries provide proof that the local environment (i.e. high temperature, low feed quality and quantity, disease and parasitic loads) can sustain composite genotypes of up to 50% B. taurus blood and does not lead to significant yield increases in upgraded groups. The economic feasibility of raising crossbred cows (Zebu x Bos taurus) under the Sudan condition has to be further evaluated in comparison with native dairy breeds to determine the overall efficiency and economic benefits. Es konnten keine signifikanten Unterschiede der Laktationsleistung, der täglichen Milchleistung und der Laktationslänge bei Kühen mit einem 25 % und 37,5 % Holstein-Friesian-Anteil gefunden werden. Die F1 50 % Zebu x HF hatten eine signifikant höhere Milchleistung (2721 ± 87 kg) im Vergleich zu den genetischen Gruppen 25 % und 37,5 % mit jeweils 2067 ± 241 und 2192 ± 123 kg. Die Laktationsleistung und die tägliche Milchleistung der genetischen Gruppen 50 %, 62,5 %, 75 % und 87,5 % waren nicht signifikant unterschiedlich. Auch gab es keine signifikanten Unterschiede in der Laktationslänge zwischen den Kreuzungsgruppen mit 25 %, 37,5 % und 50 % HF-Anteil (268 ±18; 273 ± 9 und 279 ± 6) während die Kreuzungsgruppen mit 75 % und 87,5 % HF-Anteil eine signifikant längere Laktation aufwiesen (305 ± 11 und 347 ± 30). Die Trockenperiode schwankte zwischen 78 Tagen für die 75 % HF-Gruppe und 92 Tagen für die 25 % HF-Gruppe.

Considering the hidden mode of inheritance of some coat-color-associated alleles, we investigated the presence/absence of coat-color-associated alleles in 1093 domestic horses of 55 breeds and 20 specimens of Przewalski's horse. For coat-color genotyping, allele specific PCR, pyrosequencing and Li-Cor analyses were conducted on 12 coat-color-associated alleles of five genes. Our data provide deep insight into the distribution of coat-color-associated alleles within breeds. We found that the alleles for the basic colorations (bay, black, and chestnut) are widely distributed and occur in nearly all breeds. Alleles leading to dilutions or patterns are rare in domestic breeds and were not found in Przewalski's horse. Higher frequencies of these alleles are only found in breeds that are selected for their expressed phenotypes (e.g., Kinsky horse, Lewitzer, Tinker). Nevertheless, our study produced strong evidence that molecular testing of the coat color is necessary for well-defined phenotyping to avoid unexpected colorations of offspring that can result in legal action.

This paper attempts to define a rational choice of breeding strategies for the improvement of milk production in the Sudan involving Kenana, Butana, Friesian and crossbred dairy cows. In some major production traits, the Sudanese Butana and Kenana cattle compare favourably under average station management with some of the best breeds in tropical countries, and their performance does not fall far behind that of 50% crossbred cattle in the Sudan. Kenana and Butana could be used particularly in medium-intensive production systems. The local environment (high temperature, low feed quality and quantity, disease and parasitic challenge) can sustain only composite genotypes of a moderate level of Bos taurus blood. Their relative economic efficiency is yet to be considered. An economically viable use of Friesian cattle in central Sudan is an option only when adequate feeding management, hygiene, stockmanship, technical services and other types of infrastructure are available. A regional dairy breeding policy should be established that implements breeding programmes to produce dairy cattle suitable for particular eco-regions and production systems.