Effects of long day photoperiod on milk yield and circulating concentrations of insulin-like growth factor-1 and prolactin in Jaffrabadi buffalo

Abstract

An experiment was conducted to study the effect of long day photoperiod and showering on milk production and associative endocrine changes in lactating Jaffrabadi buffaloes between November, 2013 and May, 2014 at Cattle Breeding Farm, Junagadh Agricultural University, Junagadh (India) on twenty-four recently calved Jaffrabadi buffaloes for a total duration of 182 days. The treatment groups were T₁ (control-Natural day photoperiod-NDPP), T₂ (NDPP + showering twice a day), T₃ (long day photoperiod of 18 h-LDPP) and T₄ (LDPP + showering twice a day). The buffaloes were fed as per ICAR (2010) feeding standards to meet the nutritional demands of lactation. Supplemental lighting of 20 footcandle at eye level of buffaloes in T₃ and T₄ was provided by fluorescent lamps, controlled by automatic timer. Plasma was assayed for Insulin like Growth Factor-1 (IGF-1) and Prolactin (PRL) hormones by using ELISA kit. Buffaloes in T₄ produced 27.68% (1.55 lit) more milk than control group of buffaloes, followed by T₃ group of buffaloes producing 24.0% (1.35 lit) and T₂ group of animals producing 8.93% (0.5 lit) more milk per day. Buffaloes exposed to LDPP showed greater concentrations of IGF-1 and prolactin than buffaloes exposed to NDPP. Exposure to LDPP and showering twice a day increased milk yield and circulating concentrations of IGF-1 and PRL in Jaffrabadi buffaloes indicating that IGF-1 and PRL are galactopoietic in dairy buffaloes and revealed physiological basis for possible endocrine mechanism for the galactopoietic response of both the hormones. LDPP along with showering twice a day produce synergetic effect on milk yield in Jaffrabadi buffaloes. These practices are simple to implement, easy to manage, profitable, cost effective and does not require any technological insertion and thus provide another management tool for dairy buffalo producers to enhance productivity and profitability.