A deterministic evaluation of alternative management options for the smallholder dairy cattle production system in South Africa

Abstract

The aim of this thesis was to evaluate alternative management options for the smallholder dairy cattle production system in South Africa (SA). Specific objectives included, were to benchmark cow performance in the smallholder (SH) against their counterparts in a high-input system (H), to develop a SH herd model, and to evaluate alternative management options for the improvement of smallholder dairy herd profitability. Data on production (305 day yields of milk, fat and protein), lactation length, somatic cell count (SCC), and reproductive traits (age at first calving (AFC), and calving interval (CI) obtained from the South African National Dairy Animal Improvement scheme (NDAIS) were used in a benchmarking study. Least squares means per trait were compared between the two systems, and lactation curves for production traits and SCC were plotted. Results revealed that mean yields of milk, fat and protein were significantly (P<0.05) lower in the SH (4 097±165, 174±5.1 and 141±4.5 respectively) compared to the H system (6 921±141, 298±4.7, and 245±4.1, respectively). Mean lactation length was significantly (P<0.05) shorter for the SH (308±15.1) compared to the H system (346±12.8). Log-transformed SCC was significantly (P<0.05) higher in the SH (2.41±0.01) relative to the H system (2.27±0.01). Cows in H herds exhibited typical lactation curves, in contrast to flat and low-peaking curves obtained for the SH system. SH cows had significantly (P<0.05) older AFC (30±0.5) than those in the H system (27±0.5). There was no significant difference (P<0.05) in CI between the two systems. A bio-economic SH herd model was developed by adapting a previously developed model for the H system in SA. Parameters used were obtained from NDAIS, survey data, personal communications, and literature. The model integrated herd dynamics, outputs, nutrient energy requirements, management, and their associated economics. Nutrient energy requirements were estimated for maintenance, growth, reproduction, and lactation. The developed SH herd model was used to evaluate alternative herd management options, using the partial budget approach. Milk yield (MY), live weight (LW), AFC, and CI were used as indicators of cow performance. Herd management practices studied were herd size (HS), replacement rate (RR), feeding system (FS), breeding methods (natural service vs artificial insemination), and source of replacement heifers (raising vs. buying in). Improvements in profitability were attained by increasing MY or increasing herd size, using small to medium sized cows, or reducing AFC, CI or RR. Break-even points were 3 687.4l/year, 500 kg, 29 months, 420 days and 25% for MY, LW, AFC, CI, and RR, respectively. Profitability was mostly sensitive to the prices of milk and feed. A drop in the price of milk below R4.50/l or increase in the cost of feed above R5.60/kg DM generally resulted in nonprofitability. Relying on pasture only for feed was non-viable, and supplementation of pasture with concentrate was the most profitable feeding system. Feeding systems based on supplementation of pasture with concentrate, and silage were resilient to fluctuations in the price of milk, remaining profitable even when the price dropped to R4.10/l. Using artificial insemination or buying-in replacement heifers are additional management strategies that increase SH dairy farming profitability. These recommended management options should be used in combination for achieving maximum herd profitability. Keywords: Benchmarking, Bio-economic model, high-input, production, reproduction, simulation, smallholder, somatic cell count