Carla Maris Machado Bittar

The present study evaluated the effects of sugarcane-derived polyphenol nutritional supplement on milk production, milk composition, and somatic cell count (SCC) in lactating Holstein cows. A second objective was to evaluate the quality and stability of yogurt produced with milk from supplemented cows. Sixteen cows (20 ± 2 L/d milk, 120 ± 21 days in milk, 550 ± 82 kg body weight) were assigned to either a control group or a polyphenol-supplemented group in a randomized block design for a six-week evaluation period. Milk yield and individual milk samples for composition analysis (fat, protein, lactose, non-fat solids, casein, free fatty acids, and milk urea nitrogen) were recorded weekly, and only SCC was monitored three times per week. Yogurt was produced from pooled milk of each treatment and evaluated for fermentation parameters (pH, titratable acidity), shelf life, and sensory attributes were evaluated using a triangle test (discriminative sensory analysis). Polyphenol supplementation did not significantly affect milk yield or composition (p > 0.05), but reduced SCC considerably (238 × 10³ vs. 593 × 10³ cells/mL; p < 0.01). Yogurt fermentation and storage parameters were not significantly affected by supplementation, although pH and titratable acidity changed considerably over time (p < 0.01). Sensory analysis indicated that only 37.3% of panelists correctly identified differences between yogurts, which did not differ from chance expectation in the triangle test. These results demonstrate that polyphenol supplementation can improve udder health, evidenced by reduced SCC, without compromising milk yield, composition, or yogurt quality. Polyphenols thus represent a promising nutritional supplement for enhancing dairy cow health and maintaining product quality.

Colostrum is crucial for the survival and health of neonatal calves, providing passive immunity and influencing early gut microbial colonization. This study evaluated the impact of three colostrum sources: fresh maternal colostrum (FMC), frozen maternal colostrum (FC), and colostrum replacer (CR) on the development of the fecal microbiota in Holstein calves. Fifteen newborn calves were randomly assigned to one of three treatments (n = 5 per group). Fecal samples were collected at birth (meconium), daily during the first seven days of life, and at weeks 2, 4, 8 (weaning), and 10 (post-weaning). Microbial composition was assessed using 16 S rRNA gene sequencing. Alpha diversity increased over time (P < 0.001), with no significant differences observed among treatments. Microbiota succession followed a consistent trajectory across all groups, characterized by an early dominance of Escherichia/Shigella, which gradually transitioned to increased relative abundances of Lactobacillus, Bacteroides, and Faecalibacterium over time. Notably, calves fed FMC showed a significantly higher fecal relative abundance of Lactobacillus during the first three days of life (excluding day 0, meconium) compared to those receiving FC (P = 0.046) or CR (P = 0.44), although the overall bacterial community structure was primarily influenced by calf age. These findings suggest that while colostrum source does not impact overall microbial diversity, it may modulate early colonization by beneficial bacteria. Providing fresh maternal colostrum may promote more favorable microbiota programming during the neonatal period.

The use of plant-derived polyphenols in ruminant nutrition has garnered attention as a natural approach to enhance fermentation efficiency, mitigate methane emissions, and improve animal health. This study evaluated the effects of sugarcane‐derived polyphenol supplementation on ruminal fermentation, methane emission, blood parameters, and the ruminal microbiome of lactating Holstein cows. Sixteen cows were assigned to two treatments: Control (50 mL/d placebo) or Polyphenol (50 mL/d sugarcane polyphenol extract). Ruminal fluid was analyzed for short-chain fatty acids (SCFAs) and ammonia-N, blood was analyzed for selected metabolites, methane emissions were measured using the SF6 technique, and microbial diversity and composition were assessed by 16S rRNA gene sequencing. Polyphenol supplementation increased total SCFA concentration from 58.44 to 66.44 ± 3.00 mM (P = 0.08) and raised the molar proportion of propionate from 18.13 to 18.89 ± 0.29 mM/100 mM (P = 0.08). Blood glucose concentrations were significantly higher in supplemented cows, whereas other blood parameters were unaffected. Methane emissions did not differ between groups. Microbial community analyses revealed no effect on alpha diversity measures (Shannon index and richness), but an impact of treatment and time in beta diversity, with polyphenol supplementation associated with selective shifts in bacterial taxa, including greater relative abundance of Planctomycetota. These findings indicate that sugarcane‐derived polyphenols can beneficially modulate ruminal fermentation and microbial community structure without compromising microbial diversity. The increase in propionate and blood glucose suggests enhanced glucogenic potential, while unchanged methane emissions highlight the need for further studies to clarify the conditions under which sugarcane polyphenols may mitigate greenhouse gas emissions.

Water quality plays a crucial role in calf health and performance, mainly when it is used to dilute milk replacers, which can affect the incidence of diarrhea. This study assessed the effects of municipal tap water (TW) compared with purified water (PW) on calf performance and health. Thirty Holstein calves were randomly assigned to 2 treatment groups in a randomized block design. Calves received 6 L/d of milk replacer (14% solids) diluted with the respective water treatment until gradual weaning (49-53 d). A pelleted starter was offered from birth, and chopped hay was provided ad libitum from 49 to 70 d. Dry matter intake, water intake, and health scores were recorded daily. Average daily gain was measured weekly, whereas body measurements and blood samples were collected biweekly. The PW tended to improve feed efficiency and increased ADG in the third week of life, but the final BW did not differ between treatments. Calves that received PW consumed more hay and tended to have greater water intake. Moreover, PW reduced day with diarrhea and the number of antibiotic treatments. Blood metabolites varied primarily with age, except for higher albumin concentrations in TW calves at wk 10. In summary, the PW tended to enhance performance during preweaning, particularly after diarrhea episodes. These findings highlight the importance of water quality during early life, but further studies are needed to determine the effect on dairy calf health.

This study examines the critical role of whole milk or milk replacer as a liquid diet (LD) with 15% solids in combination with different physical forms of starter as a solid diet (SD), on performance, health, and behavior of pre-weaned calves. Sixty male Holstein calves were used in a 2 × 2 factorial design, and randomly distributed into the following treatments: Whole milk powder diluted to 12.5% of solids and enriched with 25 g/L of milk replacer to achieve 15% solids, associated with either micropelleted stater (WM+micro) or texturized stater (WM+text); milk replacer diluted to 15% solids associated with either micropelleted stater (MRmicro) or texturized stater (MRtext). Starter intake and, consequently, total DMI were higher in the MRtext treatment compared to WM+micro. Calves fed texturized starter showed higher DMI, starter intake time, and rumination time. Calves in the WM+Text group showed greater ADG compared with MR treatments, regardless of starter type. Calves fed WM+ presented a lower number of days with fecal score ≥2, and the first day of diarrhea occurred at older ages. Calves fed MR showed more health challenges but similar feed efficiency with WM+, while texturized starter increased intake, eating duration, and rumination compared with micropelleted starter.

The objective of this study was to evaluate effects of social housing on calf performance and activity within different seasons. Within 24 h of birth, Holstein heifer calves were assigned to either individual (IH; n = 50 pens) or pair housing (PH; n = 50 pens), balanced across seasons in a humid subtropical climate (cool season, mid-October to mid-April, 17 ± 5°C, mean ± SD, and warm season, mid-April to mid-October, 26 ± 3°C, temperature-humidity index consistently >65). Calves received 8 L/d of milk replacer, until gradual weaning over 10 d beginning at 43 ± 3 d of age, and calf starter and water ad libitum. The presence of fever (≥39.4°C) and scours (fecal consistency assessed visually at the pen level) were assessed 5 d/wk. Calves were weighed at birth, before and after weaning, and 1 wk postweaning. Pen-level starter intake was recorded 4 d/wk. Standing time was determined using leg-based accelerometers. Calves born in the cool season scoured later and for fewer days, with no effect of social housing. Fever presentation was similarly reduced in the cool season, in interaction with housing treatment; fewer PH than IH calves had a fever in the cool season. Calves in PH pens consumed more starter by wk 5 of life, had greater ADG pre- and postweaning, and had greater BW by the end of weaning. Some performance advantages attributed to PH compared with IH calves were most apparent in the cool season, including starter intake during weaning (+0.17 kg/d; SE = 0.021) and postweaning ADG (+0.35 kg/d; SE = 0.1). Calves in PH pens maintained greater BW 1 wk postweaning, with no effect of season. Standing time was greater in PH pens, particularly in the evening, with daily peaks in activity falling later in the day during the warm season. These results support clear benefits of PH dairy calves from birth, alongside evidence that performance advantages attributed to social housing may be enhanced in cool weather or dampened by heat stress.

The diet of dairy calves can be contaminated with mycotoxins, posing a potential risk to animal health. This case study report aimed to make the first assessment of the presence of multiple mycotoxins in concentrates fed to dairy calves in Brazil. A total of 19 concentrate samples intended for dairy calves were analyzed using liquid chromatography coupled with mass spectrometry. Aflatoxins, deoxynivalenol, and T-2 toxin were not detected in any samples, whereas fumonisins B₁ (FB₁) and B₂ (FB₂) were present in 100% of the samples, with mean concentrations of 2750.1 μg/kg and 834.9 μg/kg, respectively. Zearalenone (ZEN) was detected in 36.8% of samples, with a mean concentration of 929.9 μg/kg. Significant correlations were observed between FB₁ and FB₂ (ρ = 0.978; p < 0.001) and between FB₂ and ZEN (ρ = 0.735; p = 0.05). While the physical form of the concentrate did not influence (p > 0.05) mycotoxin concentrations, a trend was observed for FB₁ (ρ = −0.417; p = 0.07) and FB2 (ρ = −0.395; p = 0.09). These findings highlight the frequent occurrence of Fusarium mycotoxins, likely due to pre-harvest contamination, emphasizing the potential risk of additive or synergistic effects in dairy calves.

Summary: This study evaluated 2 methods for adjusting whole milk solids to 15% for feeding Holstein calves: a fixed-dose approach and daily adjustment using a Brix refractometer. Thirty male calves were assigned to one of the 2 methods and monitored for 56 days. Daily Brix adjustment improved liquid diet, protein, and lactose intake, and both methods resulted in similar calf performance and health. Both strategies were effective and practical for managing milk solids on dairy farms; however, using a fixed dose of a corrector or milk replacer simplifies the feeding routine. (Images from Freepik; macrovector and brgfx.)

The inclusion of forage sources in calf diets is often discussed, and the main point debated is whether the inclusion level, particle size, source, and how forage is offered may impact gut fill and reduce body weight gain, as well as impact gastrointestinal tract development. This study aimed to determine the effects of feeding forage sources with different qualities on rumen fermentation, gut fill, and development of the gastrointestinal tract of dairy calves. Forty-eight Holstein dairy calves were blocked according to sex and body weight (BW) at 28 days of life and randomly assigned to 1 of 4 dietary treatments. Treatments consisted of a no-forage coarsely ground starter (CON) or total mixed rations containing 7.5% on DM basis of Tifton hay of either medium quality (MH) or low quality (LH) or 10% on DM basis of corn silage (CS). The nutritional content, including crude protein, NDF, lignin, and in vitro digestibility, was used as forage quality criteria. During the first 28 days of life, all calves received 3 L of whole milk twice daily, a commercial pelleted starter ad libitum, and no forage. After that, the solid diet was changed to the respective dietary treatments. Rumen samples were taken to determine rumen pH and volatile fatty acid (VFA) proportions. Calves were gradually weaned from 52 to 56 d of age, and 20 calves, 5 per treatment, were harvested two weeks after weaning. The anatomical parts of the gastrointestinal tract were weighed with and without contents, and histological analysis of rumen epithelium was conducted. The CON diet increased total VFA concentration compared to forage diets. The forage diets increased rumen pH, fecal pH, and gut fill. However, regardless of the source, the forage provision did not affect empty body weight. In addition, the forage provision increased the number of papillae in the rumen, but diets did not influence the length and width of papillae. The results suggest that 7.5% of Tifton hay, regardless of the quality, and 10% of corn silage in high-starch mixed diets benefit rumen health and promote greater gut fill without negative effects on final body weight.

Due to the synepitheliochorial placental structure, bovines show no maternal antibody flow from mother to fetus during pregnancy, resulting in an agammaglobulemic newborn