The potential of replacing conventional dairy supplements with forage legume-based diets in Zimbabwe’s smallholder dairy sector

The effect of replacing commercial supplements with isoenergetic and isonitrogenous velvet bean-, cowpeaand lablab-based supplements on milk yield, milk quality and economic returns in smallholder crossbred dairy cows was investigated in the 2013 and 2014 dry seasons. Using 3 × 3 Latin square designs, nine multiparous Red Dane, Guernsey and Holstein-Friesian crosses in mid-lactation (130 ± 19 d) were offered forage legume-based supplements for 63 d at 0.5 kg per litre of milk produced. Milk quantity and quality were significantly (P < 0.05) different among supplements in both seasons. Cows fed commercial supplements had higher milk yield than cows fed forage legume supplements. Milk fat content was significantly (p < 0.05) higher in cows fed lablab-based supplements than cows fed other supplements. Milk protein, total solids and lactose content of cows fed commercial supplements was significantly (p < 0.05) higher than those fed forage legume-based supplements, although protein content was similar to cows fed lablab-based supplements. Dietary gross margins were higher for cows fed velvet beanand lablab-based supplements by 17% and 16.5%, respectively. Based on supplement, production costs per litre of milk was higher by 28% and 23% using commercial supplements compared to velvet bean and lablab supplements, respectively.     

Evaluation of Synchronization of Oestrus Based on Gonadotrophin-releasing Hormone and Its Potential Use for Fixed-Time Breeding in Tuli Beef Cows

The objective of the experiment was to compare the reproductive post-partum performance of beef cows synchronized for oestrus using prostaglandin F₂ (PGF₂) alone or with a gonadotrophin-releasing hormone (GnRH)-based drug. Fifty-five post-partum lactating Tuli cows were randomly allocated to three groups. Two groups were synchronized using either two injections of PGF₂ (500 g Prosolvin per injection) given 11 days apart (group 1), or GnRH (12.5 g Receptal per injection) followed 6 days later by an injection of 500 g PGF₂ (group 2). The cows were bred by artificial insemination 12 h after they were observed in oestrus. Group 3 was synchronized as for group 2, but a second injection of GnRH was given 54 h after the PGF₂ injection, at which time the cows were bred by artificial insemination (AI) without detection of oestrus. Blood samples were taken from the cows in group 3 and analysed for progesterone concentration to establish which cows were cycling and in oestrus before and at the time of breeding. Detection of oestrus and breeding by AI was done over 60 days. There were no significant differences (p>0.05) among the three groups in the first service and total conception rates. The percentage of cows in oestrus within 10 days of the synchronization treatment was not significantly different (p>0.05) between groups 1 and 2. The progesterone concentrations in the cows in group 3 showed that only those that were cycling at the start of the experiment responded to the synchronization treatment and conceived after fixed-time breeding. These results suggest that combinations of PGF₂ and GnRH may be of value in synchronizing oestrus and controlling breeding in Tuli cows. However, the benefit might be greater if only cows that are known to be cycling are bred in this way.     

Promoting the use of home-mixed supplements as alternatives to commercial supplements in smallholder beef production systems in the subhumid region of Zimbabwe

The economic and performance effect of supplementing smallholder cattle by substituting commercial feed with iso-nitrogenous and iso-energetic diets based on alternative protein sources was investigated in two trials. In trial 1, three diets (commercial concentrate, commercial concentrate partially substituted with mucuna, and commercial concentrate partially substituted with lablab–cowpea) compared with veld grass were allocated to 12 cattle in a complete randomised block design. In trial 2, a double complete randomised block design with 40 cattle assigned to four forage legume-based diets, a poultry-based diet and a commercial beef concentrate was carried out. Diets were offered at 1.5% of body weight daily over 56 d. Average daily weight gain (ADWG) was measured weekly in trial 1 and fortnightly in trial 2. In trial 1, ADWG was significantly (p < 0.05) higher for animals on supplements compared with non-supplemented cattle. In trial 2, ADWG was significantly highest on the groundnut stover-based diet and least on the poultry litter diet. Supplementation had a positive effect on ADWG and economic performance of smallholder beef cattle. Substitution of commercial concentrates with alternative protein sources reduced diet costs and significantly improved gross margins.     

The effect of conditioning and natural aeration methods on rate of moisture loss and crude protein content of Lablab purpureus herbage during hay-making

The objective of this on-farm study was to develop an effective and labour-extensive method to cure forage Lablab purpureus ‘Highworth’ for resource-constrained smallholder farmers in the Goromonzi district, Zimbabwe in 2014. In a completely randomised factorial design, the drying rate of forage subjected to three conditioning treatments, viz. pressing with a plain water-filled 200 L steel drum, pressing with a water-filled 200 L steel drum covered with 14-gauge wire mesh, and chopping to 5?cm length with a machete, was compared with that of unconditioned forage. The conditioning treatments were subjected to three natural aeration methods, viz. Aframe, raised platform, and dry ground. Replicated four times, conditioned forage was cured at a swath density of 25?kg m?2 to cover 3?m2?per treatment over 28 d. Conditioning of forage had a significant (p < 0.05) effect on drying rate. However, conditioning did not have a significant (p > 0.05) effect on crude protein content. Aeration treatments did not have a significant effect (p > 0.05) on drying rate or crude protein content. Moisture loss rate was higher for forage conditioned with a wired drum and machete. Conditioning with a machete was most labour intensive compared with drum conditioning treatments. Laceration and pressing is an effective and labour-extensive conditioning method for resource-constrained smallholder farmers.     

Forage seed production and trade as a pathway out of poverty in the smallholder sector: lessons from the Zimbabwe Crop Livestock Integration for Food Security (ZimCLIFS) project

The major challenge to adoption of improved forage technologies in the smallholder farming sector is poor accessibility to seed of improved cultivars. Since 2012, the Zimbabwe Crop Livestock Integration for Improved Food Security (ZimCLIFS) project set out to address such challenges through research-for-development initiatives. The main objective was to demonstrate the potential viability of a pasture seed business using a lead farmer approach, farmer-to-farmer technology dissemination, innovation platforms and field demonstrations. Snapshot surveys were used to map forage seed distribution pathways within and outside project areas. Total land area planted to forages from the 2012/13 to 2014/15 seasons increased by 147% from 14.6 ha. In 2013, Mucuna pruriens (mucuna), Lablab purpureus (lablab) and Vigna unguiculata (cowpea) seed produced was 2 250 kg, 120 kg and 4 450 kg, respectively, and by the third season, total yield increased by 163%. Seed diffusion was within and beyond project boundaries, with mucuna (67%) and lablab (43%) seed produced in the 2013/14 season being distributed outside the project area. Highest amounts received by some farmers were US$800 and US$750 for lablab and mucuna, respectively. It was concluded that there is scope to develop formal pasture seed businesses to increase rural industrialisation and provide a pathway out of poverty in the smallholder sector.     

Forage seed value chain analysis in a subhumid region of Zimbabwe: perspectives of smallholder producers

In smallholder systems, farmers are increasingly becoming aware of the need to improve livestock productivity through production of quality fodder. This is in response to scarcity of feed, particularly in the dry season, associated with seasonal variations, land degradation and the need to meet increases in demand for livestock products. The study investigated forage seed production, marketing, challenges faced and opportunities along the value chain in Zimbabwe. Data were collected from 414 smallholder farmer households through a survey, four focus group discussions and 12 key informants. Results show that forage seed is mainly sourced from development organisations. Actors include farmer producers, seed companies, research and extension institutions, and NGOs. Seed is disseminated through sales to other farmers and organisations, sharing, seed exchanges and payment for services. Challenges include unavailability of seed, under-developed markets, weak or non-existent linkages between seed suppliers and farmers, limited knowledge on seed production and marketing, and low market prices. Forage seed have comparatively higher gross margins (US$611.61 for mucuna and US$644.14 for cowpea) compared with conventional seed such as maize (?US$382.70). Opportunities arise from the growing demand for animal products, which is associated with expanding populations and the need for improved nutrition.