Title page for ETD etd-06242003-071849


Type of Document Master's Thesis
Author Jewell, Tracy Michelle
URN etd-06242003-071849
Title Artificial Induction of Lactation in Nonbreeder Dairy Cows
Degree Master of Science
Department Dairy Science
Advisory Committee
Advisor Name Title
Barnes, Michael A. Committee Chair
Akers, Robert Michael Committee Member
Nebel, Raymond L. Committee Member
Nickerson, Stephen C. Committee Member
Pearson, Ronald E. Committee Member
Keywords
  • estrous cycle
  • dairy cattle
  • induction of lactation
Date of Defense 2002-08-09
Availability unrestricted
Abstract
Thirty-four cows (26 Holsteins and 8 Jerseys) were subjected to an estrous synchronization protocol administering 2 PGF2Ą injections 11 d apart prior to beginning the lactation-induction protocol. Artificial induction of lactation yielded a 92% success rate for Holstein cows with success defined as achieving >9 kg milk/d, and a 88% success rate for Jersey cows with success defined as achieving > 5 kg milk/d. Mean accumulated milk yield for induced cows at 150 DIM was 65% of mean yield for nontreated cows. Mean peak milk yield for lactation- induced Holsteins and Jerseys was 32 kg/d and 20 kg/d, respectively. Mean serum and milk progesterone concentrations for samples collected during the first 6 d of lactation were not different between lactation-induced and nontreated cows. However, mean serum estradiol concentrations for induced cows were higher (P <0.05) in samples collected 3 and 5 DIM. Lactation-induced cows exhibited an increase in serum alpha-lactalbumin concentrations 2 d prior to initiation of milking, reaching values of ~260 ng/ml. Mean days-to-first service was greatly reduced in cows induced into lactation compared to nontreated cows, while mean services per conception was similar between induced and nontreated cows. Mean days to conception was lower for induced cows than for nontreated cows. By 150 DIM, pregnancy rate of induced cows was 70%, whereas nontreated cows averaged 56% pregnancy rate.
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