Omitting the Dry-Off Period Negatively Affects Colostrum and Milk Yield in Dairy Goats

Abstract

Seventeen pregnant multiparous Murciano-Granadina dairy goats, kept in a semi-intensive exploitation system with once daily milking throughout lactation and 1 kidding per year (milk yield, 577 L/300 d), were used to study the effects of dry-off period length on performance during the subsequent lactation. Goats were mated at wk 29 of lactation and were assigned to 2 experimental groups according to dry-off treatment: goats that were dried off 56 d before expected kidding (D56; n = 9) and goats without dry-off (D0; n = 8). After parturition, kids were removed from their mothers and weighed before suckling. Goats were hand milked to obtain colostrum and were machine milked thereafter. Colostrum was sampled for composition and IgG analysis. Milk yield was recorded weekly during the preceding and subsequent lactations. Udders were biopsied in a sample of goats at d -65 (late lactation), d -49 (during dry-off), and d 48 (early lactation) to kidding (d 0). Apoptotic and proliferating cells in mammary tissues were detected immunohistochemically. Five goats (63%) in the D0 group dried off spontaneously at 27 +/- 4 d before kidding and were considered separately (D27). The rest of the D0 goats yielded 0.86 L/d from d -56 to kidding. Goats kidded 2.25 kids/goat, but the D0 kids had smaller birth weights (1.7 kg) than the D27 (2.2 kg) and D56 (2.1 kg) kids. Colostrum of the D0 goats contained less IgG (5.6 mg/mL) than the D27 (32.9 mg/mL) and the D56 (42.4 mg/mL) goats. In the subsequent lactation (210 d), the D0 goats produced less milk (1.78 L/d) than the D27 (2.51 L/d) and D56 (2.24 L/d) goats, with no detectable difference between the D27 and D56 goats. Apoptosis and proliferation indices increased from 0.51 and 2.09%, at d -65, to 1.75 and 7.12% at d -49 (d 7 of dry-off) in D56 goats. Despite differences in daily milk yield during early lactation (d 48) between the D0, D27, and D56 treatments (1.73, 2.68, and 2.53 L/d, respectively), no differences in apoptosis or proliferation indices were detected (D0: 0.65 and 2.48%; D27: 0.68 and 1.37%; and D56: 0.71 and 2.95%), indicating that duration of the dry period did not affect mammary cell turnover during the subsequent lactation. Omitting the dry period between lactations reduced the quality of colostrum and had negative effects on milk yield in dairy goats. Goats dried off spontaneously for 27 d were as productive as goats dried off for 56 d, indicating that less than 2 mo of dry-off may be sufficient in practice.

Ketonemia in dairy goats: Effect of dry period length and effect on lying behavior

“…Randomly assigning dry period in a controlled trial, using dairy goats where parity and the previous lactation's milk production is known (unlike in this study) is necessary to disentangle the effects of dry period length on metabolic function (similar to studies on cows; Rastani et al, 2005). However, as demonstrated by Caja et al (2006), assigning shorter dry periods may be difficult as lactation persistence varies in does, resulting in some spontaneous self-drying.…”

Effect of lactation induction on milk production and composition, oxidative and antioxidant status, and biochemical variables

“…However, similar results to those obtained in our study were found by Andrade et al (2008), who reported low yields of solids in the first week of lactation followed by increased values. Moreover, Caja et al (2006) reported lower levels of proteins, reaching only 72 % of the total protein in the colostrums of non-induced goats. According to the literature, these changes may be associated with the use of corticosteroids (Winger et al 1995).…”

Proteinograma da secreção láctea de cabras

“…O incremento do fluxo sanguíneo fornece os compostos necessários para a síntese do leite ocasionando um aumento no metabolismo das células epiteliais dos alvéolos (KOLB, 1984). A secreção produzida chamada colostro, é sintetizada devido aos efeitos inibitórios da progesterona e do estrógeno em um processo que ocorre na ausência da ordenha (CUNNIGAN, 2004 , 1974;QUILES et al, 1991;CHEN et al, 1998;LEVIEUX et al, 2002;ARGÜELLO et al, 2006;RUDOVSKY et al, 2008;YANG;ZHANG, 2009) Embora o alto teor de imunoglobulinas no colostro seja conhecido não há um consenso referente ao predomínio protéico que ocorre no início da lactação, pois alguns autores acreditam que ocorre um aumento de todas as proteínas nessa fase (QUILES et al, 1991;AULDIST et al, 1995;CUNNIGAN, 2004;MADSEN et al, 2004;TSIOULPAS;LEWIS, 2007), enquanto que outros autores associam a maior concentração de proteína no colostro aos menores valores de caseína com um predomínio das proteínas do soro lácteo (OYENIYI;HUNTER, 1978;CHEN et al, 1998;HENG, 1999;SGARBIERI, 2005;CAJA;SALAMA; MACH, 1970;MICUSAN;BORDUAS, 1976;HALLIDAY, 1978;HEARY JR.;DEVERY, 1980;RADOSTITS et al, 2000;YANG;ZHANG, 2009 mg/dL, respectivamente para cadeia leve) e valores inferiores no final do 1º mês de lactação (6,86±11,1 mg/dL, em primíparas e 12,9±10,2 mg/dL, em pluríparas para cadeia pesada e 11,8±22,2 mg/dL e 6,07±10,1 mg/dL, respectivamente para cadeia leve).…”

“…Esses resultados estão de acordo com os autores que afirmam existir no início da lactação o predomínio das proteínas do soro lácteo (OYENIYI;HUNTER, 1978;CHEN et al, 1998;HENG, 1999;SANT´ANA, 2004;SGARBIERI, 2005;CAJA;SALAMA;.…”

“…Observam-se na literatura compulsada controvérsias quanto ao predomínio protéico que ocorre na fase colostral, pois alguns autores atribuem às altas concentrações de proteína devido às proteínas do soro (OYENIYI; HUNTER, 1978;CHEN et al, 1998;HENG, 1999;SANT´ANA, 2004;SGARBIERI, 2005;CAJA; SALAMA; SUCH, 2006), enquanto que outros acreditam haver um aumento de todas as proteínas no colostro inclusive caseínas (QUILES et al, 1991;AULDIST et al, 1995;CUNNIGAN, 2004;MADSEN et al, 2004;TSIOULPAS;LEWIS, 2007) No fracionamento das proteínas durante a fase colostral e o primeiro mês de lactação de cabras da raça Saanen foram identificadas e quantificadas as seguintes frações protéicas: Lactoferrina (84,0 ± 4,0 kDa); Albumina (66,0 ± 2,0 kDa);…”