Reproductive efficiency in naturally serviced and artificially inseminated beef cows

A study was conducted to compare conception rates in 71 Tuli and 86 Afrikander beef cattle bred using either artificial insemination (AI) or the bull. Animals were bred using either artificial insemination or natural service at Matopos Research Station. Animals were grouped into three groups of heifers (parity 0; P0), second calvers (parity 1; P1) and mature cows (parity 2; P2) before being randomly assigned to one of the two breeding methods. A binary logistic regression was used for statistical analysis where breeding method (AI vs natural service) was the treatment factor and conception rate was the measured response while breed, parity and last calving date were non-treatment factors. No significant differences were observed in conception rates between breeds (P > 0.05). However, the method of breeding animals, parity and calving interval affected (P < 0.05) conception rates. The breeding method, parity and calving interval had a positive Kendall’s tau-b correlation coefficients to conception. More animals were pregnant when AI (77.6%) was used compared with natural mating (56.79%). Conception rates were significantly lower (P < 0.05) in C1 compared with C2 cattle. The odds ratio for breeding method and parity are positive and significant (P < 0.05). In conclusion, the study confirms that artificial inseminated animals had similar conception rates to naturally serviced animals for both Tuli and Afrikander breeds. As such, artificial insemination technology can be used to complement or substitute natural service in indigenous cattle’s of Zimbabwe.

     

Efforts to improve Zimbabwe communal grazing areas: a review

The management of rangelands over the past decade in Zimbabwe has been on the decline. This has resulted in degraded and depleted communal rangelands. A number of recommendations by various government departments, researchers and non-governmental organisations have been implemented. These focused on improving communal grazing areas throughout the country. Notable examples include the livestock destocking policy, introduction of grazing schemes, improved forage grasses, veld legume reinforcement and agro-forestry technology. However, success in improving communal grazing areas has been limited, with forage productivity in communal areas declining, soils still eroding, as well as loss of flora and fauna diversity. The objectives of this paper are to review factors limiting efforts to improve communal grazing areas, constraints to adoption of rangeland technologies necessary to achieve desired plant community for livestock production, and present recommendations to overcome the challenges. The review concludes that there has been limited farmer participation in efforts to improve communal grazing areas and livestock productivity, thus the low adoption of technologies to improve the grazing areas. It is therefore recommended to use participatory approach methodologies to assist communal livestock farmers to improve their grazing areas.