Preliminary investigation on stayability in Italian Mediterranean Buffalo

Animal longevity, as productive life, is an essential functional trait in the economic management of dairy herds, as well as in dairy buffalo breeding. Dairy buffalo herds have always had a lower recovery rate than dairy cows due to a higher longevity, which could be justified, among other factors, with their lower productive level. Selection criteria adopted for Italian Mediterranean Buffaloes from the National Association of Buffalo Breeders (ANASB) include several morphological traits aiming to preserve and to increase buffalo longevity. One way to quantify longevity in the herd is through the evaluation of stayability which has been defined as the aptitude for which an animal remains in the farm to a given time point. This approach uses calving date to calculate the time spent by each animal in the farm and to define stayability, assigning a value of 1 if a calving date was present or 0 otherwise. The aim of this preliminary work is to assess the stayability from the first parity up to 10 in Italian Mediterranean Buffaloes (IMB). Data from 276.415 buffalo cows registered in the ANASB studbook starting from 1989 were extracted and merged with the official milk test-day recording datasets from the Italian Breeder’s Association (AIA). The first 10 parities were retained, and the variables used were: date of birth, calving dates and culling dates. [page 32][Ital J Anim Sci vol.22:s1, 2023] 25th Congress of Animal Science and Production Association The stayability frequencies (stayability =1) were calculated to a given parity (e.g. Bstay2 = stayability at parity 2 until Bstay10 = stayability at parity 10) and between two successive calving (Bstay2–3, Bstay3–4, Bstay4–5, Bstay5–6, Bstay6–7, Bstay7–8, Bstay8–9, Bstay9–10). Stayability to a given parity was 77.2% for Bstay2; 57.9% for Bstay3; 42.4 for Bstay4; 30.6% for Bstay5; 21.4% for Bstay6; 14.5% for Bstay7; 9.90% for Bstay8; 5.7% for Bstay9 and 3.2% for Bsty10. Values of stayability between two successive calving events decrease linearly from 77.2% of Bstay1–2 to 56.6 of Bstay9–10.