Induction of Lactation by Two Techniques: Success Rate, Milk Composition, Estrogen and Progesterone in Serum and Milk, and Ovarian Effects

Abstract

Induction of lactation was attempted in 12 heifers and 12 cows with estradiol benzoate (.011 mg/kg body weight per day) subcutaneous for 10 days or that plus progesterone (.1 mg + .25 mg/kg body weight per day) for 7 days. Milking commenced on day 20 for those treated with the mixture and on day 11 for the others. Lactations were induced (minimum of 4.5 kg of milk/day) in five of six heifers and two of six cows by the mixture and in six of six heifers and three of six cows for estradiol benzoate. Milk production was 44% of herdmates in the 16 induced lactations. Cows on the single treatment had lower production than the other three groups. Ovarian status, cycling, cystic, or static, was affected adversely in 5 of 16 animals induced successfully. Two of the 16, both heifers, carried calves to term following induction. The transition to normal composition of milk was slower for single than double treatment. Lactose increased slowly to normal over the 1st wk of milking while protein decreased slowly. Estrogen and progesterone in milk of induced cows were approximately twice as concentrated as in normal postparturient cows, probably because milk production was halved.

Induced lactation in pubertal heifers: Efficacy, response to bovine somatotropin, and profitability

“…As observed in cows, induced lactation in heifers resulted in variable milk yield responses among individual animals (Smith and Schanbacher, 1974;Harness et al, 1978;Byatt et al, 1997). Peak milk yields ranged from approximately 7 kg/d (Fulkerson, 1978) to over 20 kg/d (Smith and Schanbacher, 1974) in heifers that produced milk following the induction protocol.…”

“…Success rate of induced lactation varied among studies. Smith and Schanbacher (1974) reported that 62% of the heifers induced into lactation in their study produced milk, while Harness et al (1978) reported a 92% success rate. Fulkerson (1978) induced lactation in reproductively normal heifers and reported that all animals successfully lactated; however, milk production was only 60 to 70% of the milk observed in postpartum lactations.…”

Protocolo de indução de lactação: uma abordagem histórica

“…Preocupados com a qualidade do leite oriundo de vacas ou novilhas submetidas a protocolo de indução de lactação, vários investigadores conduziram pesquisas nessa área (12,83%), como a avaliação da composição do leite (NARENDRAN et al, 1974) e os níveis de caseína ou de E2 e P4 no leite (HARNESS et al 1978;NARENDRAN et al, 1979;SAWYER et al, 1986).…”

<b>Eficácia do tratamento com antibiótico injetável associado a selante de tetos sobre a saúde do úbere de novilhas com lactações induzidas</b>

“…De acordo com esses estudos, o leite de vaca e novilhas com lactações induzidas podem apresentar um valor econômico maior por unidade de leite produzido, devido ao maior teor de sólidos (MACRINA; TOZER; KENSINGER, 2011). Vários estudos avaliaram a eficácia reprodutiva de vacas e novilhas após PIL (COLLIER; HAYS, 1975;BALL et al, 2000;HARNESS et al,1978;DELOUIS et al, 1978). Lactações induzidas em vacas quando comparadas as lactações convencionais tiveram 1,25 vs1,32 serviços por concepção, respectivamente.…”

“…Lactações induzidas em vacas quando comparadas as lactações convencionais tiveram 1,25 vs1,32 serviços por concepção, respectivamente. Além do menor número de serviços, 60% das vacas induzidas foram inseminadas, resultando em taxa de prenhez de 70% e posteriormente parindo com sucesso (JEWEL, 2002 Vários autores observaram a presença de cistos foliculares após os PILs tanto em vacas quanto em novilhas (FREITAS, 2009;HAYS, 1975;DELOUIS et al, 1978;JORDAN et al,1981;HARNESS et al, 1978), possivelmente vinculada às altas dosagens hormonais (principalmente de estrógeno e progesterona) utilizadas durante os protocolos (ERB et al, 1973;COOK et al, 1990…”