Effect of Age at First Calving on First Lactation Milk Yield, Lifetime Milk Production And Longevity of Cows

Abstract

The objective of the study was to analyse the effect of age at first calving (AFC) on first lactation milk yield, lifetime milk production and longevity of dairy cows. The study used SYMLEK data on the milk yield and culling of 111 857 Polish Holstein-Friesian cows from the active population in Pomerania and Kujawy, Poland. The cows first calved during 2000–2009 and were used or removed from the herds until the end of 2015. For each cow, calculations were made of first lactation milk yield, lifetime milk production, first lactation milk yield per milking day, lifetime milk production per day, as well as the lifespan (length of productive life, duration of rearing) and number of calvings. Based on the age at first calving (duration of the rearing period), the cows were grouped as follows: ≤22, 22.1–24.0, 24.1–26.0, 26.1–28.0, 28.1–30.0, 30.1–32.0 and >32 months. The GLM, CORR PEARSON and FREQ procedures from the SAS package were used in the statistical calculations. Considering first lactation milk yield, lifetime milk production and longevity, it is recommended that the cows should be first milked between 22.1 and 26.0 months of age. This is supported by the approximately 24% higher lifetime milk production in relation to the latest calving cows (P<0.01). Late commencement of the first milking (especially after 28 months) causes a considerable decrease in the first lactation milk yield and lifetime milk production, shortens the productive period, reduces the number of calvings, and increases culling rate due to low milk yield and udder diseases.

Effect of Age at First Calving and First Lactation Milk Yield on Productive Life Traits of Syrian Shami Cows

“…This could be due to the fact that cows calved early had longer PL and more NL, LMP and LDMY compared to those calved late, in addition, there is a negative correlation between age at first calving and number of lactations and lifetime milk production. Similar results were found by Sawa et al, (2019) on Polish Holstein-Friesian and Sawa and Bogucki (2010) on Australian Holstein cows. Eastham et al, (2018) found that reducing age at first calving was associated with improving reproductive performance and increasing of number of lactations on Holstein and Holstein-Friesian cows in the UK.…”

“…This could be due to those cows calved early started productive life early, so they had longer PL compared to those calved late, in addition, there is a negative correlation between age at first calving and productive life. Sawa et al (2019) and Curran et al, (2013) arrived at the same conclusion on Holstein cows in Poland and USA, respectively. Sawa and Bogucki (2010) indicated cows had AFC ⩽22 months had the longest productive life.…”

“…The correlation coefficients between AFC and each of PL and NL were negative and highly significant (p<0.01). Sawa et al (2019) found that the correlation coefficients between AFC and each of PL, LMP and NL were -0.08, -0.11 and -0.099, respectively.…”

The Use of Artificial Neural Networks and a General Discriminant Analysis for Predicting Culling Reasons in Holstein-Friesian Cows Based on First-Lactation Performance Records

“…This results, among others, from an association between the performance of primiparous cows and their lifetime production [ 20 , 21 ]. In this regard, the current attempts at searching for an association between certain production traits and culling reasons in cows are promising [ 22 , 23 ]. However, a qualitatively and quantitatively optimal selection of variables for prediction models and the use of sufficiently accurate analytical methods still remain a challenge.…”

Characterization of Some Productive and Reproductive Traits of Syrian Shami and Holstein Cows Under Syrian Conditions

“…Decreasing AFC can provide a lot of anumber of calving and milk production from cows during their lifespan and reduces high replacement costs. The typical AFC should be around 24 months (Sawa et al, 2019).…”