Cow-calf contact
Interest in cow-calf contact systems is growing, yet limited research had been focused on cowcalf contact in a pasture setting. A study by Johanssen et al (2024) (10.1016/j.livsci.2024.105502) aimed to evaluate the performance of pastured dairy cows and calves with or without cow-calf contact through machine milk yield and composition, cow body condition score and body weight decrease, and calf body weight gain. They also examined calf intake of concentrates, artificially reared calves' milk intake, and the health of both cows and calves. The study included 20 cow-calf pairs divided into two treatments: cow-calf contact (n=10) or early separation (ES, n=10).
Cow-calf contact pairs had full cow-calf contact on pasture until 6 weeks postpartum and part-time contact in weeks 7 and 8 (weaning). Early separation pairs were separated 1–3 h after birth, kept on separate pastures with no contact between early separation cows and calves. Early separation calves received daily milk allowances of 12–14 L (weeks 0–6), reduced to 8 L (week 7) and then 4 L (week 8). From week 9, all calves were denied access to any milk (early separation) or cows (cow-calf contact). During weeks 0–6, cow-calf contact cows had a daily machine milk yield 23.7 kg/cow lower than early separation cows, this persisted during weaning, with cow-calf contact cows delivering 8.3 kg cow/day less in weeks 10 and 11 postpartum. Fat and protein content in machine milk showed no significant difference, while lactose content was lower in milk from cow-calf contact cows than early separation cows. Cow-calf contact cows had a lower body weight decrease compared to early separation cows (cow-calf contact: 913 g/day; early separation: 1415 g/day). Early separation calves had an average milk intake of 10.7 L/calf/day (weeks 0–6) and consumed more concentrates than calf-cow contact calves. Calves' daily body weight gain did not differ between treatments in weeks 0–6 and decreased for both treatments during weaning. Inhibited milk ejection during machine milking was a challenge in cow-calf contact cows, prompting oxytocin injections to prevent mastitis. Further research is needed to explore strategies to enhance milk ejection in pastured cow-calf contact cows.
A second study by Sinnott et al (2024) (10.1016/j.livsci.2024.105492) also investigated the effects of full-time cowcalf contact outdoors on pasture (FT-O), part-time contact indoors (PT-I), or no contact indoors (NC-I) on calf health, behaviour, growth and labour in a pasture-based dairy system. Cows (n=55) were balanced precalving on parity, milk production of previous lactation, breed and predicted calving date. Contact pairs bonded for 48 h, whereas NC-I calves were separated from cows immediately and remained in individual pens for 3 days before grouping. The FT-O pairs moved outdoors at 5±3.3 days, with calves only separated from cows for milking twice daily. Part-time cows were milked once-a-day (8:00) and grazed outdoors post-milking, returning indoors to calves from 15:00–08:00 the following morning. The NC-I calves were assigned to a feeding plan offering up to 9.5 L/day of milk replacer via automatic feeder.
All calves had ad libitum access to water, concentrates and forage. For NC-I calves, weaning started at 48 days, taking 12 days, for contact calves it started at 58 days, taking 7 days. From birth to 3 weeks post-weaning, animal health and labour were evaluated twice-weekly, weight and linear body measurements were recorded weekly, and behaviour was recorded weekly (daily during weaning). Following this, weighing was carried out fortnightly.
Faecal related issues were seen more often in contact calves than NC-I calves. The PT-I calves also experienced eye issues more often than NC-I and FT-O calves. Illness resulted in 26% of FT-O calves being removed from the experiment (none removed from NC-I and PT-I). The PT-I calves expressed the most abnormal behaviours throughout weaning.
The NC-I calves weighed less at 28 (49.0 vs 55.5kg), 56 (69.0 vs 82.1kg), 70 (79.0 vs 87.1kg) and 77 (81.8 vs 90.8kg) days than FT-O and PT-I calves. Labour associated with calving was greater for the NC-I system than contact systems. Weekly labour was greater for the FT-O system than NC-I and PT-I systems, which were similar. To conclude, pre-weaning calf growth and reduced labour at calving as a result of cowcalf contact is challenged by calf health and human welfare (related to daily labour) in the FT-O system and by calf behaviour and stunted post-weaning growth in the PT-I system. Thus, cow-calf contact in pasture-based dairy systems require further research to safeguard calf and human welfare.
Omphalitis
Omphalitis is the third most common cause for diseases and infections in newborn calves. To identify and quantify the risk factors of omphalitis in cow-calf operations with a seasonal indoor calving period Perrot et al (2024) (10.1016/j.prevetmed.2024.106191) investigated 964 calves from 22 cow-calf operations in central France. A prospective cohort study involved data collection during two visits for each calf.
Simple and multivariable logistic regression analyses evaluated the association between omphalitis and the variables. In total, 311 (32.3%) calves had an omphalitis. In summary, results of this study should help identify animals at particular risk (>50 kg body weight, male, short umbilical cord (<3 cm)) and focus attentions on the importance of calving-pen bedding (wetness and cleanliness) and navel disinfection in controlling omphalitis.