Effect of stocking rate and supplementation on performance of dairy cows grazing native grassland in small-scale systems in the highlands of central Mexico

Abstract

The use and management of native grassland for dairy production during the rainy season was studied on two small-scale dairy farms in the highlands of central Mexico. Two stocking rates (2 and 4 cows/ha) and two levels of supplementation with commercial concentrate (4 and 6 kg/cow/day) under grazing were given to 12 milking Holstein cows in a 4 × 4 Latin square design replicated three times in a factorial arrangement. Net herbage accumulation (NHA), sward height, chemical composition, and in vitro digestibility of organic matter were recorded for the grassland, as well as vegetation cover and herbage mass 12 weeks post experiment. Animal performance variables were milk yield and composition, live weight, and body condition score. A partial budget analysis of feeding costs, returns, and margins was calculated. There were no differences between periods for NHA and herbage height and between plots for chemical composition (P > 0.05). However, there were highly significant differences among periods (P < 0.01) for organic matter, neutral detergent fibre (NDF), acid detergent fibre, in vitro organic matter digestibility (IVOMD), and estimated metabolisable energy (eME), with highly significant plot × period interactions (P < 0.01) for NDF, IVOMD, and eME. There were no statistical differences (P > 0.05) between treatments for milk yield, chemical composition of milk, live weight, or body condition score. Post-experimental vegetation cover was 72 % for both stocking rates, indicating there was no degradation of the grassland. Lower feeding costs were for the low supplementation treatments. It is concluded that a high stocking rate in studied native grasslands of 4 cows/ha with moderate concentrate supplementation supports a mean milk yield of 11.9 kg/cow/day during the rainy season without deleterious effects on the grassland.

Black oat (Avena strigosa Schreb.) grazing or silage for small-scale dairy systems in the highlands of central Mexico. Part I. Crop and dairy cow performance

“…Milk composition and MUN values were similar to reports from previous work in the study area (Sainz-Sánchez et al, 2017;Plata-Reyes et al, 2018).…”

Productive and economic response to concentrate supplementation by grazing dairy cows at high stocking

“…Estimation of net herbage accumulation (NHA) was from cutting to ground level with shears 0.5 m 2 (2.0 x 0.25 m) quadrants, within five exclusion cages. NHA (Kg DM ha -1 d -1 ) was the difference between herbage cut inside the cage on d 21 and herbage found outside the cage on d 0, then cages where placed randomly in the sward (11,12,13) . Samples of cut herbage were oven-dried (60 °C) air forced for DM analysis.…”

“…These dry weights were used to calculate the herbage mass on a DM basis. Herbage height (cm) was recorded with a rising plate metre twice weekly, taking 20 recordings following a zigzag pattern (10,11) .…”

Use of information and communication technologies in small-scale dairy production systems in central Mexico

“…Mexico, with an annual production of approximately 11 billion liters of milk per year, ranks 8th compared to other nations of the world (SIAP, 2019). The small-scale dairy systems contribute with 35% of the national milk supply and represent over 78% of dairy farms (Sainz-Sánchez et al, 2017). These systems are generally situated in rural areas and also share some limitations such as low access to credits, low technological level, low availability of land, and lack of professional training (Kuivanen et al, 2016).…”