Differences in the fecal microbiota of dairy calves reared with differing sources of milk and levels of maternal contact

INVITED REVIEW: Impact of Maternal Health and Nutrition on the Microbiome and Immune Development of Neonatal Calves

This comprehensive review highlights the intricate interplay between maternal factors and the co-development of the microbiome and immune system in neonatal calves. Based on human and mouse studies, multiple prenatal and postnatal factors influence this process by altering the host-associated microbiomes (gut, respiratory tract, skin), microbial colonization trajectories, and priming of the immune systems (mucosal and systemic). This review emphasizes the importance of early life exposure, highlighting postnatal factors that work in synergy with maternal factors in further finetuning the co-development of the neonatal microbiome and immunity. In cattle, there is a general lack of research to identify the maternal effect on the early colonization process of neonatal calves (gut, respiratory tract) and its impact on the priming of the immune system. Past studies have primarily investigated the maternal effects on the passive transfer of immunity at birth. The co-development process of the microbiome and immune system is vital for lifelong health and production in cattle. Therefore, comprehensive research beyond the traditional focus on passive immunity is an essential step in this endeavor. Calf microbiome research reports the colonization of diverse bacterial communities in newborns, which is affected by the colostrum feeding method immediately after birth. In contrast to human studies reporting a strong link between maternal and infant bacterial communities, there is a lack of evidence to clearly define cow-to-calf transmission in cattle. Maternal exposure has been shown to promote the colonization of beneficial bacteria in neonatal calves. Nonetheless, calf microbiome research lacks links to early development of the immune system. An in-depth understanding of the impact of maternal factors on microbiomes and immunity will improve the management of pregnant cows to raise immune-fit neonatal calves. It is essential to investigate the diverse effects of maternal health conditions and nutrition during pregnancy on the gut microbiome and immunity of neonatal calves through collaboration among researchers from diverse fields such as microbiology, immunology, nutrition, veterinary science, and epidemiology.

Periodontitis Disease in Farmed Ruminants-Current State of Research

Periodontal disease in ruminants is common and occurs in farmed and wild animals. Periodontal lesions can result from the secretion of endotoxins by pathogenic bacteria and as consequences of immune system activity. Three main types of periodontitis have been described. The first is chronic inflammation involving mainly premolars and molars-periodontitis (PD). The second type is an acute inflammatory reaction occurring with calcification of the periosteum of the jawbone and swelling of the surrounding soft tissues (Cara inchada, CI-"swollen face"). Finally, a third type, similar to the first but located in the incisor area, is called "broken mouth" (BM). Etiological variation between the different types of periodontitis is indicated. This particularly manifests in the composition of the microbiome, which is characteristic of the different forms of periodontitis. The widespread detection of lesions has drawn attention to the current nature of the problem.

The Influence of Feeding with Colostrum and Colostrum Replacer on Major Blood Biomarkers and Growth Performance in Dairy Calves

Bovine colostrum (BC) is the first milk produced by lactating cows after parturition. BC is rich in various amino acids, proteins, and fats essential for the nutrition of the neonate calves. Despite the evident beneficial effect of BC on calves, the effect of BC on blood biomarkers is poorly understood. Calves that received BC showed significantly higher body mass at days 7 and 30 (38.54 kg and 43.42 kg, respectively) compared to the colostrum replacer group (p = 0.0064). BC induced greater quantities of blood neutrophils (0.27 × 10⁹/L) and monocytes (4.76 × 10⁹/L) in comparison to the colostrum replacer (0.08 and 0.06 × 10⁹/L, respectively) (p = 0.0001). Animals that received BC showed higher levels of total serum protein (59.16 g/L) and albumin (29.96 g/L) in comparison to the colostrum replacer group (44.34 g/L and 31.58 g/L, respectively). In addition, BC induced greater intestinal mucus production in the Wistar rat model. Collectively, these results demonstrate that BC is important for the growth of calves and that it provides a significant beneficial effect on morphological and biochemical blood parameters.

Effect of Type of Cow-Calf Contact on Health, Blood Parameters, and Performance of Dairy Cows and Calves

Prolonged cow-calf contact (CCC) could potentially improve dairy calf welfare. However, it is currently unknown how different types of CCC affect animals' biological functions. We evaluated health and performance parameters of dairy calves and their dams, where calves: (i) had no contact with their dam (NC), in which the calf was removed from the dam directly after birth (n = 10); (ii) were allowed to have partial contact (PC) with their dam, in which the calf was housed in a calf pen adjacent to the cow area allowing physical contact on the initiative of the dam but no suckling (n = 18); (iii) were allowed to have full contact (FC) with their dam, including suckling, in which calves were housed together with their dams in a free-stall barn (n = 20). Throughout the first 7 weeks postpartum, data were collected on the health status, fecal microbiota, hematological profile, immune and hormonal parameters, and growth rates of calves, and on the health status, metabolic responses, and performance of dams. Overall, FC calves had more health issues (P = 0.02) and a tendency for higher antibiotic usage (P = 0.07) than NC calves. Additionally, FC calves showed elevated levels of erythrocytes, hematocrit, hemoglobin, and leukocytes on day 49 compared to NC calves (P < 0.001). Calf fecal microbiota changed over time, and we found preliminary evidence that fecal microbiota is affected by the type of CCC, as reflected by differences in relative abundances of taxa including Lactobacillus in FC calves compared to NC and PC calves except on days 7 and 66. The FC calves had a greater average daily gain in body weight than NC and PC calves (P = 0.002). Cow health was not affected by the type of CCC, although in the first 7 weeks of lactation FC cows had a lower machine-gained milk yield accompanied by a lower fat percentage than NC and PC cows (P < 0.001). These results indicate that full contact posed a challenge for calf health, presumably because the housing conditions of FC calves in this experimental context were suboptimal. Secondly, ad libitum suckling leads to higher weight gains and negatively affected milk fat content besides machine-gained yields. More research into strategies to improve cow-calf housing and management in CCC systems is warranted.