Impact of Feed Quality and Quantity on Dairy Cow’s Milk Yield and Composition

Abstract

The objective of this study was to assess the effect of feed composition (both quantity and quality of the feed offered) on milk yield, lactation length and milk quality of crossbred dairy cows (Holstein-Friesian × Local) in smallholder farms in the Khulna region of Bangladesh. The data from the field were collected using structured interviews with the farmers from October 2025 to February 2026. The feed quantity and the feed quality aspects had a total of 390 cow-level observations each. Cows were classified according to a feed supply level (so sufficient, moderate, or poor) and feed quality (good, moderate, or poor). The measured parameters were daily milk yield, lactation length, compositional parameters, physico-chemical parameters of milk (density, pH, salt content, freezing point, and electrical conductivity). The data obtained from the experiments was analyzed using one way analysis of variance and Duncan's Multiple Range Test (DMRT) at 5% level of significance in SPSS version 25.0. The results revealed that the amount of feed, as well as the quality, had a highly significant effect (p < 0.001) on both the daily milk yield and the lactation length. The cows fed high feed produced 16.78 kg/day in comparison to 14.56 kg/day for moderate feed and 11.32 kg/day for poor feed. The cows fed good-quality rations had a daily production of 15.67 kg, while the moderate and poor-quality rations groups had daily productions of 14.16 and 11.13 kg, respectively. Feeding conditions had a significant effect on lactation, with a long lactation period of 286.94 days obtained under adequate feeding, a moderate period of 279.20 days obtained under good feeding quality and, in both poor feeds, a short lactation period of 206.02 days and 183.92 days for poor feeding quantity and quality respectively. The results of regression analysis showed that feed supply level alone accounted for 98.9% of the variation in daily milk yield (R² = 0.9885) and 99.2% of variation in lactation length, and feed quality accounted for 96.4% and 95.7% respectively. Interestingly, milk compositional parameters such as fat, protein, total solids, SNF, lactose and ash, as well as all physico-chemical properties, did not differ statistically (p > 0.05) among the different feeding groups. The trend of total solids (TS%) as a function of feed level was weak and non-significant (R² = 0.2002), and thus showed that there was little meaningful relationship between feeding level and milk solids content despite the strong effect feeding level had on milk volume. This indicates that, although poor feeding reduces the amount of milk produced, and the duration of lactation, it doesn't affect the nutritional value of the milk produced. To conclude, the point for Khulna farmers is that the enhancement of feed quality and quantity is one of the most effective and direct investments they can make to increase their dairy income.

Keywords: Lactation length, Milk quality, Physico-chemical properties of milk, Ration quality.

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