Effects of exposure to artificial long days on milk yield, maternal insulin-like growth factor 1 levels and kid growth rate in subtropical goats.
This study was designed to determine whether any relationship exists between exposure to artificial long days, milk yield, maternal plasma insulin-like growth factor 1 (IGF-1) levels, and kid growth rate in goats. One group of lactating goats was maintained under naturally decreasing day length (control group; n = 19), while in another one, they were kept under artificial long days (LD group; n = 19). Milk yield was higher in goats from the LD group than that in the control group (P < 0.05). Maternal IGF-1 levels at day 57 of lactation were higher (P < 0.05) in goats from the LD group than the levels in the control group and were positively correlated with the total milk yields per goat at days 43 and 57 of lactation (r = 0.77 and r = 0.84, respectively; P < 0.01). Daily weight gain at week 4 was higher (P < 0.01) in kids from the LD group than that in kids from the control group and was correlated with total and average IGF-1 maternal levels (r = 0.60 and r = 0.60, P < 0.05). It was concluded that submitting lactating goats to artificial long days increases milk yield, plasma IGF-1 maternal levels and the growth rate of the kids.
Centro de Investigación en Reproducción Caprina (CIRCA), Universidad Autónoma Agraria Antonio Narro, Torreón, Coahuila, Mexico.
Horacio
H
Hernández
Centro de Investigación en Reproducción Caprina (CIRCA), Universidad Autónoma Agraria Antonio Narro, Torreón, Coahuila, Mexico.
José Alfredo
JA
Flores
Centro de Investigación en Reproducción Caprina (CIRCA), Universidad Autónoma Agraria Antonio Narro, Torreón, Coahuila, Mexico.
José Alberto
JA
Delgadillo
Centro de Investigación en Reproducción Caprina (CIRCA), Universidad Autónoma Agraria Antonio Narro, Torreón, Coahuila, Mexico.
Ilda G
IG
Fernández
Centro de Investigación en Reproducción Caprina (CIRCA), Universidad Autónoma Agraria Antonio Narro, Torreón, Coahuila, Mexico.
Manuel de Jesús
Mde J
Flores
Centro de Investigación en Reproducción Caprina (CIRCA), Universidad Autónoma Agraria Antonio Narro, Torreón, Coahuila, Mexico.
Ángel
Á
Mejía
Transportadora de Alimentos, LALA, Gómez Palacio, Durango, Mexico.
José Manuel
JM
Elizundia
Centro de Investigación en Reproducción Caprina (CIRCA), Universidad Autónoma Agraria Antonio Narro, Torreón, Coahuila, Mexico.
Marie
M
Bedos
Centro de Investigación en Reproducción Caprina (CIRCA), Universidad Autónoma Agraria Antonio Narro, Torreón, Coahuila, Mexico.
José Luis
JL
Ponce
Centro de Investigación en Reproducción Caprina (CIRCA), Universidad Autónoma Agraria Antonio Narro, Torreón, Coahuila, Mexico.
Sergio
S
Ramírez
D000818:Animals; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D006041:Goats / Q000254:growth & development* / Q000502:physiology*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D007774:Lactation / Q000502:physiology*; D008297:Male; D017440:Photoperiod; D015430:Weight Gain
D007334:Insulin-Like Growth Factor I
IGF-1; goat kid growth; lactation; photoperiod