Report

The effect of body condition score change 15 days prior to calving on lactation curve and production parameters in grazing dairy cows in Ireland M.R. Sheehy*1,2, F.J. Mulligan1, M.A. Crowe1, S.P.M. Aungier1, and A.G. Fahey3 1School of Veterinary Medicine, University College Dublin, Ireland Nutrition Ltd., Belfast, Northern Ireland 3 School of Agriculture & Food Science, University College Dublin, Ireland 2Devenish Introduction • The transition period extends from 3 weeks before to 3 weeks after calving • It is the most critical period of the lactation – Nutrition and energy balance – Production – Metabolic Health Issues • Economic and welfare implications Introduction OUTPUTS INPUTS ENERGY BALANCE Energy balance can be assessed during transition by body condition score change Previous Studies Have been concerned with the implications of cows reaching target BCS at various stages of lactation Stage Dry off Calving Breeding 150 to 250 days in milk Body Condition Score 2.75 – 3.00 3.00 – 3.25 Minimum 2.75 2.75 – 3.00 (Mulligan, 2012) However, little is known about the effect of BCS change immediately pre-calving on the lactation characteristics of the dairy cow Objective To determine if change in BCS in the last 15 days before calving has an affect on subsequent lactation characteristics Materials and Methods • Commercial Irish dairy farm • 98 Spring-calving Holstein-Friesian cows 305 day yields Milk (kg) Fat (kg) Protein (kg) 9125 331 298 Fat (%) Protein (%) SCC (‘000 per ml) 3.62 3.27 308 Calving Interval (days) 445 Treatments MAIN – cows that maintained BCS 15 d prior to calving LOSS – cows that lost BCS 15 d prior to calving Parity 1 N ∆ BCS MAIN 23 0 LOSS 8 -0.28 Parity 2 N ∆ BCS 12 0 15 -0.25 Parity 3 N ∆ BCS 20 0 20 -0.32 Body Condition Scoring • 1 to 5 BCS scale (Edmonson et al., 1989) • Same trained researcher every 2 weeks • Eliminate inter-observer variation Dairy Cow BCS Body Condition Score (BCS) Records Analysis Milk Sampling • Cows milked at 0700 and 1600 h daily • Milk was sampled every two weeks – Mid infrared spectrophotometry – Milk, fat, and protein yields – Fat, protein, and lactose concentrations • Energy Corrected Milk (KirchgeBner 1997) (Milk yield x 0.3246) + (Fat yield x 12.86) + (Prot yield x 7.04) Lactation Curve Modelling • Woods Incomplete Gamma Function (Woods, 1967) • Non-linear function • y(t) = atbe-ct – – – – t = time a = estimate of initial milk yield b= rate of increase until peak production c = rate of decrease after peak production Curve Shape Shape Parameter Curve Shape description b c C1 + - Standard lactation curve C2 + + Continuous increase C3 - - Continuous decrease C4 - + Inverted lactation curve b a c Lactation Curve Characteristics • Initial milk yield (a) • Rate of increase to peak yield (b) • Rate of decline after peak yield (c) • Lactation persistency (p) • Time at which peak yield is attained (Tm) • Peak yield (Ym) Statistical Analysis Yijkl = BCS + Ci + Tj + Pk + TPjk + TCij + PCki+ eijkl Yijkl = lactation curve characteristics of the lth cow in ith calving month, the jth treatment, and the kth parity, BCS = covariate of BCS on d -15 Ci = the ith calving month of Jan, Feb, Mar, or Apr Tj = the jth treatment of MAIN or LOSS Pk = the kth parity of 1, 2, or ≥ 3 TPjk = the interaction of the jth treatment and the kth parity TCij = the interaction of the jth treatment and the ith calving month PCij = the interaction of the kh parity and the ith calving month eijkl = random residual error Results: Milk (kg) MAIN Parity 1 Parity 2 LOSS Parity 3 Parity 1 Parity 2 Significance Parity 3 T P T×P Milk a c tm Ym 20.75 22.53 24.54 16.18 17.79 21.04 (2.34) (2.75) (2.23) (3.53) (2.67) (2.16) -0.005Aa -0.006 -0.006B -0.007b -0.006 -0.007 (0.0005) (0.0004) (0.0004) (0.0007) (0.0005) (0.0005) 56.24ACc 45.79B 43.51D 48.99d 46.72 44.47 (4.35) (4.20) (3.63) (6.04) (4.07) (3.12) 35.82CE 40.33D 46.02F 34.06E 39.77EF 44.36F (1.21) (1.42) (1.24) (1.74) (1.31) (1.06) <0.05 NS NS <0.10 NS NS <0.10 NS NS NS <0.01 NS Results: Fat (kg) MAIN LOSS Significance Parity 1 Parity 2 Parity 3 Parity 1 Parity 2 Parity 3 6.62a 6.41 6.42 6.15b 6.44 6.33 (0.10) (0.19) (0.14) (0.23) (0.16) (0.14) 42.66 45.72 53.38c 40.71 40.70 34.79d (6.12) (8.11) (5.78) (12.12) (6.99) (5.87) 1.11E 1.34F 1.33F 1.25 1.24A 1.37B (0.04) (0.06) (0.04) (0.09) (0.05) (0.05) T P T×P NS NS NS NS NS NS Fat kg P tm Ym NS <0.05 NS 305 Day Production Yields MAIN Parity 1 Parity 2 LOSS Parity 3 Parity 1 Parity 2 Significance Parity 3 Milk 7573.51CE 8352.29DE 9329.21F 6873.65E 8445.86AF 9126.74BF (kg) (240.35) (284.42) (232.48) (362.43) (276.44) (224.38) Fat 238.89E 276.53C 330.65DF 248.65 272.14 298.88 (kg) (16.24) (20.58) (16.48) (25.59) (19.10) (16.11) Prot 238.03E 269.32CF 294.40DF 218.80E 266.03EF 294.21F (kg) (6.69) (7.92) (6.47) (10.09) (7.69) (6.25) SCC 108.57A 157.62 252.60aB 164.89C 247.99 369.12bD (,000) (63.41) (58.62) (48.37) (88.61) (59.04) (45.65) T P T×P NS <0.01 NS NS <0.01 NS NS <0.10 NS <0.05 <0.05 NS Summary • Overall – – – – MAIN significantly greater initial milk yield (a) than LOSS MAIN significantly lower SCC than loss LOSS cows tended to reach peak milk yield sooner LOSS cows tended to have a faster rate of decline post peak • Parity 1 – MAIN took longer to reach peak milk yield – MAIN lower rate of decline post peak milk yield – MAIN more persistent fat yield curve • Parity 3 – MAIN took longer to reach peak fat yield – MAIN had lower somatic cell count Conclusion • Ideal lactation curve – Cows that reach peak milk and component yields slowly and remain persistent – More beneficial to the cows’ metabolic and health status (Solkner and Funchs, 1987) • Therefore MAIN parity 1 and parity 3 cows had improved lactation curve characteristics compared to LOSS parity 1 and parity 3 Thank you for your attention The effect of body condition score change 15 days prior to calving on lactation curve and production parameters in grazing dairy cows in Ireland M.R. Sheehy*1,2, F.J. Mulligan1, M.A. Crowe1, S.P.M. Aungier1, and A.G. Fahey3 1School of Veterinary Medicine, University College Dublin, Ireland Nutrition Ltd., Belfast, Northern Ireland 3 School of Agriculture & Food Science, University College Dublin, Ireland 2Devenish Lactation Curve Characteristics • Initial milk yield (a) • Rate of increase to peak yield (b) • Rate of decline after peak yield (c) • Lactation persistency (p) – p = -(b+1)*ln(c) • Time at which peak yield is attained (Tm) – Tm =b/c • Peak yield (Ym) – Ym = a(b/c)be-b