the present study investigated the effects of replacing ground corn with full-fat corn germ on milk production, milk composition, and nutrient utilization in cows fed sugarcane bagasse and cactus cladodes. Ten multiparous Girolando cows (average body weight 500 ± 66 kg, 90 ± 15 days in milk) were distributed into a replicated 5 x 5 Latin Square, and assigned to five dietary treatments containing 0%, 25%, 50%, 75%, or 100% of full-fat corn germ in substitution to ground corn. Full-fat corn germ increased energy-corrected milk yield and synthesis of fat, lactose, and total solids in milk (p < 0.05). Cows fed corn germ quadratically increased (p < 0.05) intake of dry matter, crude protein, and total digestible nutrients, and linearly reduced (p < 0.05) the intake of total non-fiber carbohydrates. Except for ether extract and non-fiber carbohydrates, full-fat corn germ did not alter (p > 0.05) nutrient digestibility. Feeding corn germ reduced (p < 0.05) the excretion of urea-N in milk and N excretion via urine. These results demonstrate that full-fat corn germ can partially replace ground corn to enhance production efficiency in crossbred cows fed cactus cladodes and sugarcane bagasse. Furthermore, including sugarcane bagasse in FFCG-supplemented diets prevents milk fat depression in cows fed cactus cladodes.

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Sustainability - the new hype of the 21 st century has brought discomfort for the government and society. Sustainable agriculture is essential to face our most concerning challenges: climate change, food security, and the environmental footprint, all of which add to consumers' opinions and choices. Improvements in reproductive indexes can enhance animal production and efficiency, guaranteeing profit and sustainability. Estrus detection, artificial insemination (AI), embryo transfer (ET), estrus synchronization (ES), and multiple ovulations are some strategies used to improve animal reproduction. This review highlights how reproductive strategies and genetic selection can contribute to sustainable ruminant production. Improved reproductive indices can reduce the number of nonproductive cows in the herd, reducing methane emissions and land use for production while preserving natural resources.

Dairy cattle systems have targeted improvements in feed efficiency by selecting animals that can convert less feed into more products. Residual feed intake (RFI) has been the index of choice when selecting dairy cattle for feed efficiency. Nonetheless, RFI studies have focused on lactating cows, and the crucial importance of pre-weaning efficiency on farm profitability and cow productivity has been mostly neglected. This review discusses the current knowledge of how RFI divergence relates to nutrient metabolism in pre-weaning dairy calves, including the advantages and limitations of evaluating RFI in this phase. Existing literature indicates that nutrient utilization, energy metabolism, protein metabolism, vitamin metabolism, intestinal development, and hindgut bacterial populations may be implicated in RFI divergence between pre-weaning calves. Techniques developed to date to evaluate RFI in this phase are still evolving to better adapt to the unique characteristics of this phase, and more research is needed to fill in the gaps in our current understanding of early-life feed efficiency divergence in cattle. However, current results suggest great potential for selecting high-efficiency calves while in pre-weaning to accelerate the progress of genetic selection in dairy cattle.