Influence of feeding different ratios of forage to concentrate and methionine hydroxy analog supplementation on growth performance of Holstein heifers

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Abstract: The objective of this experiment was to evaluate the effects of altered forage: concentrate ratio and DL-methionine analogue supplementation on growth performance of growing heifers until breeding weight (330 kg BW). Twenty-four Holstein heifers with an average of age 5.6 ±0.36 mo and weight 116 ± 6 kg, were fed restricted intakes formulated to allow for 800 g/d. Experimental diets were formulated to contain either 50 :50 (low forage) of 75: 25 (high forage) forage: concentrate ratio diets dry mater (DM) basis. Forage comprised of corn silage (CS) and constant amounts of berseem hay (1.5 and 2 kg/h/ d for low and high forage, respectively). Treatments were fed with or without Methionine Hydroxy Analog supplementation (MHA, 2.1 g / day/ 100 kg BW). Live body weight (LBW) was taken biweekly, while some body measurements and blood samples were taken monthly. Blood plasma were taken twice weekly during three consecutive week from 280 kg LBW to determine the peak of plasma progesterone (P4). Digestibility trial was performed after three months of the trail (at 170 kg LBW), during the digestibility trial heifers were fed individually in tie-stall. Actual intakes of nutrients were lower than expected intakes due to lower corn silage DM ratio. OM, CP, NFE and EE digestibility were significantly (P < 0.05) improved by reducing the forage portion of the diet, however CF digestibility had a significant (P < 0.05) opposite direction. While, supplementation of MHA resulted in trends toward increased CF and EE digestibility . insignificant differences were absorbed for plasma total protein triglyceride, creatinine, urea and peak of P4, in addition to negligible difference for albumin, globulin, A/G ratio, and transferases (AST and ALT) while significant (P<0.05) decreasing in plasma cholesterol was recorded for low forage without MHA treatment. Throughout the feeding period, ADO was not affected across all treatment rations (0.675 LF. 0.679 HF, 0.715 LFM. 0.666 HFM. SE± 0.032 kg/d). Gain of heifers body weight and measurements and age at 330 kg BW, were not different among treatments, however age at 330 kg BW was recorded an average of 15.98 mo (15.85 LF, 16.26 HF, 15.41 LFM, 16.38 HFM, SE±0.52 mo). Whereas, low forage groups had significantly (P < 0.05) better feed-conversion for DM TDN and DCP, Daily cost for high forage groups was signiticantly (P < 0.05) better than low forage groups, even though there is a deep gap within treatments in total feed cost, especially in high forage groups, thus it's was insignificantly influence between treatment in economic efficiency, Thus, we can feed growing heifers in this tested forage strategy under quality recommended for feedstuffs, and method of feeding. Notwithstanding, MHA addition did not have effect on growth of heifers, nevertheless MHA addition may have influences on CF digest and body metabolism, and may be the amount used was not enough to improve growth performance.
Keywords: Holstein heifers, forage: concentrate digestibility, growth performance.

Publication year

2010

Pages

91-105

Availability location

معهد بحوث الانتاج الحيوانى- شارع نادى الصيد- الدقى - الجيزة

Availability number

Organization Name

Animal Production Research Institute (APRI)

serial title

Egyptian Journal Nutrition and Feeds

ISSN