We evaluated the performance, milk composition, and milk fatty acid profile of cows fed diets composed of cactus cladodes (Opuntia stricta [Haw.] Haw), sugarcane bagasse and increasing levels of full-fat corn germ (FFCG). We hypothesized that ground corn can be effectively replaced by FFCG when cactus cladodes and sugarcane bagasse are used as forage sources. The cows were randomly distributed into two 5 × 5 Latin Squares and fed five diets in which ground corn was progressively replaced with full-fat corn germ (FFCG; 0%, 25%, 50%, 75%, or 100% of substitution). Adding FFCG to the diet increased milk production and milk fat content and reduced milk protein content. Overall, FFCG reduced the proportion of saturated FAs and increased mono- and polyunsaturated FAs in milk, including CLA isomers. In addition, activity indices of stearoyl-CoA desaturase were reduced by increasing levels of FFCG. We conclude that the substitution of corn for FFCG in diets based on cactus cladodes and sugarcane bagasse positively modifies the FA profile of milk and could add commercial value to milk products (e.g., CLA-enriched milk). In addition, the milk fat response indicates that the basal diet was favorable to the rumen environment, preventing the trans-10 shift commonly associated with milk fat depression.

This study aimed to evaluate the effects of replacing earless corn silage (ECS) with cactus cladodes (CC; Opuntia spp.) and sugarcane bagasse (SB) on nutrient intake, digestibility, feeding behavior, milk yield (MY), and composition of lactating dairy cows. Ten Holstein cows, weighing 571 ± 97.0 kg and producing 23.0 ± 4.4 kg of milk per day, were assigned to two contemporaneous 5 × 5 Latin squares. Treatments consisted of five levels of ECS replacement with CC plus SB (0, 25, 50, 75, and 100%). The results showed a linear increase in dry matter (DM) intake (p < 0.05) (15.98 and 18.73 kg/day) and a quadratic increase (p < 0.05) in crude protein and energy intake (2.97 kg/day and 27.52 Mcal/day at 95.4 and 88.6% substitution, respectively). Apparent DM digestibility increased (p < 0.05), but fiber digestibility decreased linearly (p < 0.05). Treatments had a quadratic effect (p < 0.05) on MY and fat-corrected MY (24.17 kg/day and 21.9 kg/day at 63.9% and 38.6% CC plus SB, respectively). Milk fat (3.26 and 2.35%) and total solids content decreased linearly (p < 0.05), whereas the percentages of protein, lactose, and nonfat solids increased (p < 0.05). Additionally, the CC–SB diets linearly reduced the time spent on feeding and rumination and total chewing time. For Holstein cows fed common semiarid diets, milk production can be maximized by replacing 38.6% of ECS with CC plus SB.

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.

Diarrhea and respiratory diseases pose significant challenges in the rearing of pre-weaned calves, motivating the investigation of tools to improve gastrointestinal tract development, health, and overall performance in young calves. Consequently, the primary objective of this study was to assess the effectiveness of an additive incorporated into milk replacer to promote the development and health of the animals. Forty-six dairy calves were randomly assigned into two treatments: control (CON, n = 23; with 15 females and 8 males), and sodium butyrate (SB, n = 23; with 15 females and 8 males). The calves in the SB treatment group were supplemented with 4 g/d of unprotected sodium butyrate (Adimix, Adisseo, China), added to the milk replacer from 4 to 60 days of age. Water and starter were fed ad libitum. The study evaluated several parameters, including feed intake, nutrient digestibility, ruminal pH, ammonia and volatile fatty acids, blood metabolites (glucose, insulin-like growth factor type 1, urea, β–hydroxybutyrate), hemogram, health scores, performance, and feed efficiency. Bull calves were euthanized at 60 days of age for organ comparison, while heifer calves were assessed for carryover effects up to 90 days of age. Data were analyzed independently using linear mixed models using the nlme package in R, and the Artools package for non-parametric categorical outcomes. Although the feed intake and performance variables exhibited differences within weeks, no divergence was observed between treatment groups. Notably, a positive treatment-by-week interaction was identified for starter feed intake (p = 0.02) and total dry matter intake (p = 0.04) during pre-weaning for CON animals. Ruminal parameters, blood metabolites, and hemogram values such as glucose, urea, insulin-like growth factor type 1, mean corpuscular value, lymphocytes, and neutrophils displayed differences within weeks during the pre-weaning stage, but similar results within groups. No differences between supplemented and non-supplemented calves were found across nutrient digestibility, organ development, and histology. Regarding health scores, differences were noted within weeks for fecal and respiratory scores during the pre-weaning stage, and only the respiratory score during the post-weaning stage. Consequently, butyrate supplementation did not elicit improvements or negative effects in the body development or health status of dairy calves.

The present study explored the combined effects of CC (Opuntia stricta [Haw.] Haw.) and full-fat corn germ (FFCG) as a source of supplementary PUFA on milk fatty acid (FA) composition of dairy goats fed elephant grass (EG). Twelve Saanen goats were used in a replicated 4 × 4 Latin square design in a 2 × 2 factorial arrangement of treatments (GC or FFCG as energy sources, and the inclusion or not of CC in the diet as a partial substitute for EG). The proportions of various milk FAs were influenced by CC, FFCG, or both. Significant interactions between CC and FFCG were noted for most trans-C18:1 and CLA isomers. Specifically, including CC in the FFCG-supplemented diet increased the levels of trans-11 C18:1 and cis-9, trans-11 CLA in milk fat, whereas these isomers were unchanged or slightly reduced with CC in the GC diet. Similar patterns were observed for C18:2 n-6, while C16:0 increased with CC in the GC diet. Ratios of trans-C18:1/C18:0 and trans-11 C18:1/C18:0 were notably higher when CC was included in the FFCG-supplemented diet. These findings suggest that CC inhibits the last step of rumen biohydrogenation in dairy goats, enriching milk with trans-11 C18:1 and cis-9, trans-11 CLA when supplementary PUFA is provided in the diet.