Vitality in Newborn Farm Animals: Adverse Factors, Physiological Responses, Pharmacological Therapies, and Physical Methods to Increase Neonate Vigor

**Background:** Vitality in newborn farm animals describes the vigor and general health state during the first hours of life, assessed through numerical scores adapted from the human Apgar system. These scores evaluate heart rate, respiratory rate, mucous membrane coloration, time to stand, and meconium staining. Factors such as intrauterine hypoxia, dystocia, low birth weight, glycogen depletion, hypothermia, and neurodevelopmental immaturity can compromise neonatal vitality and increase mortality risk. Pre-weaning mortality in piglets in EU countries remains around 15%, with some as high as 25%, often due to crushing associated with postnatal hypoglycemia and hypothermia. This review aims to analyze pharmacological and physical therapies used to increase vitality in newborn farm animals and understand the factors affecting it.

**Methods:** This is a narrative review synthesizing existing literature on factors affecting neonatal vitality in farm animals (pigs, cattle, sheep, goats, horses, rabbits) and therapeutic interventions. The authors examined intrinsic factors (hypothermia, hypoxia, birth weight, glycogen depletion, neurodevelopment, dystocia) and physiological mechanisms for achieving thermostability (brown adipose tissue thermogenesis, shivering, vasomotor control, postural changes). They then reviewed pharmacological therapies (caffeine, naloxone, dextrose/glucose, oxygen therapy) and physical methods (colostrum supplementation, external heat sources, drying).

**Key Results:** - Hypothermia: Newborn temperature can drop up to 3.5 °C after expulsion from the uterus. Pre-weaning mortality in piglets in EU countries remains around 15%, with some as high as 25%. - Birth weight: Low-birth-weight newborns have liver glycogen and skeletal muscle reserves decreased by 70–85%, and available lipids are only about 10% of those in adequate-weight animals. Up to 74% of calves with reduced vigor die before weaning. - Caffeine: Administration at 20–30 mg/kg 8 h after birth in piglets with asphyxia increased body weight by 19% at weaning. In Merino lambs, 20 mg/kg caffeine showed nonsignificant effect on mortality. Combined caffeine (30 mg) and glucose (30 mg) in low-birth-weight piglets improved growth by 0.9 kg between days 1 and 3. - Naloxone: In rabbit pups at 4 mg/kg, minute volume increased by 50 mL and tidal volume by 8%, with a 5 mmHg decrease in CO₂ and 2 mmHg increase in pO₂. In piglets, naloxone increased phrenic neural activity and respiratory output by 122 ± 36%. - Oxygen therapy: Intranasal oxygen in calves with respiratory distress increased PaO₂ by 20.3 ± 8.8 mmHg and SaO₂ by 10% within the first 12 h, with survival of 9/10 in treatment vs. 4/10 in controls. - Colostrum: Piglets with serum IgG <1000 mg/dL had only 67% chance of survival during the first 72 h. In Holstein calves, colostrum powder (10 g IgG in 70 g) resulted in less diarrhea (6.1% vs. 9.7%) and mortality (7.7% vs. 26.1%), though not statistically significant. Piglets fed milk replacement had 57% mortality (8/14). - Drying: Drying newborn piglets or drying plus heat lamp reduced mortality to approximately 6% vs. 12% in controls. Drying plus heat lamp reduced crushing by sow (13.6% vs. 47.9%). Desiccant plus warming box (35 °C) resulted in highest rectal temperatures (37.6–38.6 °C vs. 36.7–37.7 °C in controls). - Dextrose: Intraperitoneal administration of 10 mL/kg of 20% glucose plus rewarming at 40 °C improved survival in lambs. Combined glucose and colostrum resulted in higher blood glucose levels than either alone.

**Clinical Implications:** The review emphasizes that systematic vitality assessment immediately after birth is essential to determine newborn health and identify those needing medical intervention to minimize effects of intrapartum asphyxia. Vitality assessment should be conducted by trained personnel with adequate equipment. The authors recommend increasing the number of stock people during expected parturition days to reduce long-term neonatal morbidity and mortality. Combined approaches—including colostrum supplementation, external heat sources, drying, and appropriate pharmacological support—are recommended over single interventions. The review notes that caffeine administration alone is insufficient and should be combined with energy supplements. Infrared thermography is proposed as a non-invasive method to assess thermal state. The authors suggest exploring additional drugs such as sildenafil or doxapram for their cardiovascular effects in counteracting hypertension, acidemia, and hypoxia during the postpartum period.