Estimation of Dairy Cow Survival in the First Three Lactations for Different Culling Reasons Using the Kaplan–Meier Method

Abstract

The aims of the study were: (i) to compare survival curves for cows culled for different reasons over three successive lactations using the Kaplan–Meier estimator; (ii) to determine the effects of breeding documentation parameters on cow survival; (iii) to investigate the similarity between culling categories. The survival times for a subset of 347,939 Holstein-Friesian cows culled between 2017 and 2018 in Poland were expressed in months from calving to culling or the end of lactation. The survival tables were constructed for each culling category and lactation number. The survival curves were also compared. The main culling categories were reproductive disorders—40%, udder diseases—13 to 15%, and locomotor system diseases—above 10%. The survival curves for cows from individual culling categories had similar shapes. A low probability of survival curves for metabolic and digestive system diseases and respiratory diseases was observed in each of the three lactations. The contagious disease category was almost non-existent in the first lactation. The greatest influence on the relative culling risk was exerted by age at first calving, lactation length, calving interval, production subindex, breeding value for longevity, temperament, and average daily milk yield. A more accurate method of determining culling reasons would be required.

Mortality in Galla Goat Production System in Southern Rangelands of Kenya: Levels and Predictors

“…Based on the Kaplan-Meier functions, the cumulative survival decline could be observed and this translate to an increase in the Cumulative mortality for the entire period of about 29%. The proportion surviving Galla goat on this day seems to be relatively high and ranges from 0.922 to 0.991. comparable survival probability for cows culled for different reasons was observed in Grzesiak et al (2022) study. The causes of mortality in Galla goat and their relative contribution to the mortalities based on the data collected during the 2014-2021 study period are presented in Table 4.…”

“…However, we cannot exclude those goats since otherwise sample size of the study may become small. The Kaplan-Meier method allow us to compute the survival over time in spite of such difficulties associated with subjects or situations (Goel et al, 2010;Grzesiak et al, 2022). Therefore, for each time interval, survival probability was calculated as the number of Galla goats surviving divided by the number of Galla goats at risk.…”

“…Therefore, for each time interval, survival probability was calculated as the number of Galla goats surviving divided by the number of Galla goats at risk. The total probability of survival till that time period was calculated by multiplying all the probabilities of survival at all-time intervals preceding that time (by applying law of multiplication of probability to calculate cumulative probability) [Kaplan & Meier, 1958;Grzesiak et al, 2022]. Then, the probability of Galla goat dying (cumulative mortality) is 1 (one) minus the probability of Galla goat survival (cumulative survival).…”

Milk recording data indicates the importance of fertility, including age at first calving, on the progression of first lactation cows to second lactation

“…In the Swedish study, poor fertility (conventional, 32% of culls; organic, 31% of culls), udder health (conventional, 15%; organic, 21%) and low milk production (9% of culls in both types) were the most common reasons given for first lactation cows not progressing to second lactation [ 4 ]. Likewise, in Poland, first lactation HF cows are frequently culled due to poor fertility (43.9%) and udder diseases (13.0%) [ 5 ]. In Estonia, 16% of first lactation Holstein, Red and Native cows did not progress to second lactation, of which 25% were culled due to feet/claw disorders, 18% due to udder disorders and 15% due to fertility problems [ 6 ].…”

Maternal, Postnatal, and Management-Related Factors Involved in Daily Weight Gain and Survivability of Suckling Zaraibi Goat Kids in Egypt

“…This advantage is important for studying events such as a mortality rate in livestock farms, which is time dependent. Applying survival analysis allows for the use of records from surviving (censored) and dead (uncensored) animals/kids, as both records can be used jointly and introduced into the analysis, therefore all the available data about the animals/kids are properly used [ 6 , 7 ]. The obtained data might permit managers to follow better management techniques to reduce mortality rates and maximize profits.…”