Dystocia is expected to occur in ~10%–15% of first-calf heifers and in 3%–5% of mature cattle. Although dystocia cannot be eliminated from a herd, the incidence can be greatly decreased by management decisions made before the breeding season and during gestation. Dystocia is an important welfare issue and should be targeted for control.
Nutrition for Calving Management in Cattle
Heifers and cows should maintain body condition before calving; however, overconditioning leads to excess fat deposition in the udder and results in lower milk production. Excessive fat deposition in the pelvis may also result in dystocia. Good body condition aids in calving ease, early return to cyclicity in beef cows, and also milk production. There is a balance to achieve between excessive condition, potentially leading to dystocia, and insufficient condition leading to postcalving subestrus/anestrus.
Facilities for Calving of Cattle
Dedicated calving facilities may be needed in many herds. They should be in good repair and functional before the calving season starts. Weather conditions, geographic differences, and local experience usually dictate how much attention and individual care calves will need immediately after birth. The calving environment (eg, calving sheds, small pastures) must be clean, dry, and protected from the weather. A clean area to handle dystocia problems is also needed.
Calving in a clean area, separated from the rest of the herd, helps to decrease calfhood diseases, particularly diarrhea (scours) and paratuberculosis Paratuberculosis in Ruminants Paratuberculosis, caused by Mycobacterium avium paratuberculosis , is a chronic, contagious granulomatous enteritis characterized in cattle and other ruminants by progressive weight loss... read more (Johne disease). In large herds, the availability of several small calving pastures to enable regular rotation may help to decrease the buildup of pathogens. When calving stalls are used during inclement weather, they should be cleaned and disinfected between calvings. Technologies such as high-resolution closed-circuit television (CCTV) and radiofrequency identification sensors linked to smartphones have emerged as valuable aids to calving management.
Calving in Cattle
Close observation of labor is necessary to determine when or whether a delivery should be assisted. CCTV or sensor alerts can be invaluable in this process. Labor is divided into three stages:
Stage 1 begins with uterine contractions and dilation of the cervix and ends with passage of the amnion and part of the fetus into the vagina. This stage may last 1–24 hours; 1–4 hours is normal.
Stage 2 is characterized by abdominal contractions due to presence of the fetus in the vaginal canal and ends with expulsion of the fetus through the vulva. Birth should be expected within 1–4 hours for heifers. A mature cow should calve in < 3 hours if presentation of the calf is normal; if no progress is evident within 1 hour, assistance may be required.
Inappropriate intervention or social-group stresses may disrupt labor. Appropriately timed calving strategies are based on the need to minimize social-group changes at the point of calving, because these social changes are associated with challenges to the intake of dry-matter feed, as well as disrupted labor and increased risk of stillbirth.
Stage 3 is expulsion of the fetal membranes and the initiation of uterine involution. The fetal membranes normally are expelled within 12 hours after parturition.
Feeding preparturient cows in the late morning (11:00 am–12:00 noon) and again at night (9:30–10:00 pm) encourages cows to calve during the day (7:00 am–7:00 pm), when a problem is more likely to be identified and assistance more likely to be available.
Parturition is too often difficult for both fetus and dam. Many factors affect the extent of difficulty, including breed, age, nutrition, and pelvic area of the dam; breed and genotype of the sire; gestation length; and sex, size, position, and presentation of the fetus. Some of these factors are directly influenced by management, and the problems associated with them may be preventable.
When dystocia develops, survival of both dam and calf depends on proper assistance, which requires identification of the problem, proper facilities, and adequate help. A delay in assisting may mean loss of the calf, and/or injury or death of the cow. However, it is important to allow sufficient time for the dam to dilate before applying traction. Before assisting the delivery, the position of the fetus must be determined accurately, and any abnormal presentation corrected. If the calf is simply too large to pass through the birth canal without danger to the cow or calf, a cesarean section or other surgical assistance may be necessary.
Management After Calving in Cattle
Muddy lots, crowding, filth, chilling, and inclement weather make the calf more vulnerable to pathogens. Adequate feed trough space (ie, 1 meter per fresh cow) and lying space in bedded yards (ie, 1.25 m2/1,000 kg milk production) are key factors for freshly calved dairy cows to maximize feed intake and minimize risk of poor hygiene on udder health for cows. Adequate colostrum intake for calves is critical at this time. Preventing transmission of Johne disease from cow to neonatal calf is a major consideration in calving hygiene and colostrum collection and feeding.
Passive Transfer of Immunity in Cattle
Calves receive immunity passively from the dam through the ingestion of colostrum. The calf’s immune system is immature at birth and depends on the acquisition of passive immunity for disease protection in early life. Immunoglobulins (IgG and IgM) and lymphocytes are absorbed directly across the gut into the calf’s circulation to provide immunity. The ability of the gut to absorb these large molecules and cells is a transient phenomenon; gut closure is complete by 24 hours, and absorption has decreased significantly markedly by 6–8 hours of age after birth.
The ingestion of adequate amounts of high-quality colostrum as early as possible after birth is important for calf survival and growth. Calves with failure of passive transfer (FPT) are 3–9 times more likely to become sick before weaning, and 5 times more likely to die before weaning than are calves with adequate passive transfer.
Minimizing the incidence of FPT passive-transfer failure should emphasize dystocia management, proper nutrition, and intervention for calves at high risk of FPT such failure. Cows that have dystocia should be milked out immediately, and the calf actively-fed should be actively fed colostrum to ensure ingestion. Target 3-4 litres The target should be 3–4 L as soon as possible after calving, by naso-gastric nasogastric tube as necessary. Cows with poor udder conformation or mastitis should be milked and the colostrum fed to the calf to ensure timely intake.
Colostrum supplements may not prove adequate as shown in controlled clinical trials in elevating serum IgG levels may be inadequate for elevating serum IgG concentrations, as controlled clinical trials have shown. Vaccination of the cow before calving with antigens causing that cause enteric disease in calves may be a useful adjunct to good overall management in reducing decreasing morbidity. Hygienic management of colostrum is vital to effective absorption, and either careful pasteurisation pasteurization or cooling of lidded containers should be considered.