Herd health observations in an intensively managed cow-calf production system

Abstract Text: Given heightening interest in alternative cow-calf production systems, data regarding animal health are critical, yet limited in the literature.  This report presents cow-calf health observations from 2 years of a continual study evaluating the feed efficiency of early weaning in an intensively managed (total drylot confinement) cow-calf production system.  Multiparous (4.6 ± 1 year), crossbred (Red Angus × Red Poll × Tarentaise × South Devon × Devon), lactating beef cows (n = 156) with summer-born calves at side were blocked by prebreeding BW (H, M, L), stratified by calf age, and assigned randomly to 1 of 4 treatments within strata.  The study was a randomized complete block design with a 2 × 2 factorial arrangement of treatments with three replications (pens) per treatment per year (total n = 24).  Treatment factors were: 1) location; eastern (ARDC) or western (PHREC) Nebraska and 2) calf age at weaning; 91 ± 18 (EW) or 203 ± 16 (NW) d of age.  At each location, EW cows and calves and NW pairs were fed a common diet (60:40 distillers grains:crop residue [year 1]; 40:40:20 corn silage:distillers grains:crop residue [year 2], DM basis) from the time of early (October) to normal (January) weaning.  Cattle were maintained in earthen feedlot pens adjacent to other cattle during calving (prior to trial initiation) and the weaning portion of the study.  Cows received two annual vaccinations: 1) prior to calving (ScourGuard 4KC) and 2) prior to breeding (Bovi-Shield Gold FP 5 VL5 HB).  Calves were vaccinated: 1) at birth (Vision 7 Somnus) and 2) at 90 d of age (Vision 7 Somnus + Bovi-Shield Gold 5).  Data were analyzed using the GLIMMIX procedure of SAS.  Incidences of cow morbidity and neonatal calf diarrhea were absent.  However, occurrence of bovine respiratory disease (BRD) in calves varied by location and year.  Bovine respiratory disease rates across weaning treatments were 0% and 26% (P ≤ 0.01) at PHREC and ARDC, respectively (year 1).  In year 2, 0% and 84% (32 of 38) of calves were diagnosed with BRD at ARDC and PHREC, respectively (P ≤ 0.01).  While calves were 3.5-5.0 months of age when treated for BRD, no mortality was observed regardless of year or location.  Divergence in BRD incidence was likely related to stressors including weaning, weather, and exposure to other animals.  These data are essential for developing recommendations for producers managing cowherds in alternative production systems.                           

Keywords: cow-calf pairs, health, production system