Estimation of daily milk yield of Nellore cows grazing tropical pastures

Abstract

Beef cows' milk yield is typically determined by measuring milk yield once daily and then doubling this value to estimate daily production. However, it is not known whether this is accurate. Thus, we aimed to determine the association between morning and afternoon milk yield in grazing Nellore cows. Eighty Nellore cows were used, with initial weight of 516.0 ± 1.0 kg. The experiment was a completely randomized factorial scheme, with 20 replications and four treatments (i.e., + or - pre-partum supplementation in combination with + or - post-partum supplementation): PRMM-1 kg of supplement/cow/day for 90 days pre-partum; MMPS-1 kg of supplement/cow/day for 90 days post-partum; PRPS-1 kg of supplement/cow/day for 90 days pre-partum and 90 days post-partum; and MM-only mineral mix ad libitum during pre- and post-partum. Milk was sampled on days 45, 135, and 225 post-partum (early, middle, and late lactation, respectively). No effects were observed of pre- and post-partum supplementation on milk yield (P > 0.05). The afternoon/morning proportion of 0.45 in the early third of lactation was higher than other stages, which had a proportion of 0.41 (P < 0.05). Post-partum supplementation increased milk protein in the morning and afternoon milking (P < 0.05). There was also no effect of pre- and post-partum supplementation on afternoon-morning proportion other milk components (P> 0.05). We conclude that estimating daily milk production of grazing beef cattle by multiplying a once daily milking amount times two is not accurate. Under the conditions of this study, proportion of total daily production represented by the ratio of afternoon/morning milking was 0.45 in early lactation (first third) and 0.41 in mid- and late lactation.

Feed efficiency and maternal productivity of Bos indicus beef cows

“…Nellore beef cows reported lower uncorrected MY (3.16±0.31 and 3.70±0.33 kg/day) [19,20] and corrected for 4% fat MY (7.0 kg/day and 7.2, 5.0 and 4.1 kg/day in early, mid and late lactation) [21,22] than the means observed in the present study.…”

Milk Production and Constituents of Beef Cows with Different Breed Compositions

“…In this study, the lactose content (4.6-4.86%) is within that described by the NRC [27], which mention that it can vary from 3.84 to 5.66%. Furthermore, these results are similar to those reported by other studies in NENE (4.36-5.1%) [50,52], Charolais Regarding the lactation period, the nutritional contents also changed over time (Table 5). Protein content and total solids had a significant increase (P < 0.05) in each period analyzed.…”

“…05%, similar to that found in ANAN, Brahman, Angus-Brahman and Brahman-Angus cows (3.1-4.0%)[4], and lower than that found in NENE cows (4.3-4.8%)[18,50]. The concentrations of protein in this study (2.9 to 3.3%) were similar to those reported in ANAN, Brahman, Angus-Brahmanand Brahman-Angus (3.3-3.4%), [4] NENE (2,86-3.6%) (Almeida et al 2018) and Charolais, Nellore-Charolais and Charolais-Nellore cows (2.86-3.17%) [51].…”

The “Grass-Fed” Milk Story: Understanding the Impact of Pasture Feeding on the Composition and Quality of Bovine Milk

“…Protein synthesis is one of so many complex physiological processes that occur in the mammary gland and requires vast amounts of energy. Protein production can vary considerably between and within the various genetic groups of cows [122]. Although these genetic differences between breeds exist, feeding system has also been shown to impact milk and protein yield [123].…”