Effect of Body Condition Score at Calving on 305-day and Test-day Milk Yield in Holstein-Friesian and Brown Swiss Cows

Abstract

ABSTRACT The study included 37 cows, 20 of which were of the Holstein-Friesian and 17 of which were of the Brown Swiss breed at the Agricultural Institute's farm in Stara Zagora. The cows from both breeds were kept together under similar rearing and feeding conditions. A free-range production system with individual boxes for rest was applied. The cows were divided into three technological groups depending on their physiological condition, respectively: dry period, first lactation period (up to the 120th day of lactation) and second lactation period. Feeding was based on a complete ration including maize silage, alfalfa haylage, concentrated feed, and vitamin mineral premix. The concentrated feed during lactation was in accordance with the group's mean milk yield. The cows' body condition score (BCS) was measured monthly per a 5-grade evaluation system with accuracy of up to 0.5 points. The body condition score of the cows at calving was measured 7 to 10 days before calving. The BCS at calving had a significant influence on the 305-day lactation milk yield, test-day milk yield and peak lactation production. The cows that reached a BCS of 3.5 – 4 points at calving had sufficient body reserves for the lactation's beginning, which allowed them to reach higher milk yield during the peak of lactation, and higher yield for 305 days compared to cows with grades of 3 or lower at calving. The Holstein-Friesian cows had better mobilisation potential than Brown Swiss cows. At BCS of 2 to 2.5 points at calving, Holstein-Friesian cows reached a milk yield that was only 876 kg less than those of cows with high BCS (3.5 – 4 points), whereas in Brown Swiss cows the difference was 1,400 kg. The cows of the Brown Swiss breed had preserved to a greater extent the defence reaction to reduce milk production when body reserves were diminished. Key Words: Body condition score evaluation, 305-day lactation, peak lactation, test-day milk yield, Holstein-Friesian, Brown Swiss cattle OZET SIYAH ALACA VE ESMER IRK INEKLERDE BUZAĞILAMA ONCESI VUCUT KONDISYON SKORUNUN 305 GUN VE TEST-GUNU SUT VERIMI UZERINE ETKILERI Arastirma, Stara Zagora Ziraat Enstitusu Ciftligindeki 20 bas Siyah Alaca ve 17 bas Esmer olmak uzere toplam 37 bas inek ile yurutulmustur. Her iki irktan inekler benzer yetistirme ve besleme kosullarinda bakilmislardir. Ineklere serbest gezinmeli sistemde dinlenme icin bireysel bokslar saglanmistir. Inekler fizyolojik durumlarina gore uc gruba ayrilmislardir: a) Kuru donem, b) I. laktasyon periodu (laktasyonun 120. gunune kadar) ve c) II. laktasyon periyodu. Misir silaji, kuru yonca, konsantre yem ve vitamin - mineral premiksi iceren rasyona dayali bir besleme programi uygulanmistir. Laktasyon suresince verilen konsantre yem, grubun ortalama sut verimine gore duzenlenmistir. Ineklerin vucut kondisyon skoru (VKS), 5 dereceli degerlendirme sistemi ile 0,5 puanlik kesinlik ile aylik olarak olculmustur. Buzagilama oncesi VKS, buzagilamadan 7-10 gun once olculmustur. Buzagilama oncesi VKS'nun 305-gun laktasyon sut verimi, test gunu sut verimi ve pik sut verimi uzerine etkisi onemli bulunmustur. Buzagilama oncesi VKS 3,5-4 puan olan ineklerin laktasyon baslangicinda yeterli vucut rezervlerine sahip olduklari ve boylece VKS 3 ve daha az olan ineklerle karsilastirildiginda laktasyon pikinde daha yuksek sut verimine ulastiklari ve daha yuksek 305-gun laktasyon sut verimine sahip olduklari sonucuna ulasilmistir. Siyah Alaca ineklerin Esmer ineklerle karsilastirildiginda daha iyi mobilizasyon potansiyeline sahip olduklari gozlenmistir. Siyah Alaca irkinda buzagilama oncesi VKS 2-2,5 olan inekler, 3,5-4 VKS olanlara kiyasla sadece 876 kg daha az sut verimine sahip iken, Esmer ineklerde aradaki fark 1400 kg olarak belirlenmistir. Vucut rezervleri azaldiginda Esmer irk inekler sut verimini azaltma savunma reaksiyonunu daha fazla ortaya koymuslardir. Anahtar Kelimeler: Vucut kondisyon skoru degerlendirmesi, 305 gun laktasyon, laktasyon piki, test-gunu, sut verimi, Siyah Alaca, Esmer