Lactation failure in crossbred Sahiwal Friesian cattle

Abstract

Milk producers in Malaysia make extensive use of crossbred Sahiwal Friesian dairy cattle. These animals have, however, been found susceptible to lactation failure. A survey of cows in an experimental herd of F1 Sahiwal Friesian animals indicated that, in 30% of animals, milk yield decreased to negligible levels within the first 8 weeks post partum. Lactation failure was associated with a progressive increase in the amount of residual milk left in the udder after normal milking. By week 3 of lactation, residual milk volume was significantly greater than that in animals that, based on previous lactation history, were not susceptible to lactation failure, and accounted for up to 30% of milk available at the morning milking. The cellular consequences of residual milk accumulation were evident in the activities of acetyl-CoA carboxylase, fatty acid synthetase and galactosyltransferase, key enzyme markers of cellular differentiation, which decreased in glands undergoing lactation failure and were lower than values measured in tissue of control cows. Mammary cell number, estimated by tissue DNA content, was also reduced in animals undergoing lactation failure. These indices of mammary development indicate that lactation failure is the result of premature involution in susceptible animals. Premature involution is a predictable consequence of progressive milk stasis in failing lactation, and attributable to an increase in autocrine feedback by inhibitory milk constituents. The progressive increase in residual milk is, on the other hand, unlikely to be attributable to impaired mammary development. Measurements of milk storage during milk accumulation showed no differences between control and lactation failure cows in the distribution of milk between alveolar and cisternal storage compartments. We conclude that lactation failure in Sahiwal Friesian cows is due to a failure of milk removal, and probably the result of an impaired milk ejection reflex rather than to the glands' milk storage characteristics.

Milk yield, residual milk, oxytocin and cortisol release during machine milking in Gir, Gir × Holstein and Holstein cows

“…Additionally, all experimental groups produced milk at levels comparable with those described by other authors [7,20], and the Gir and GirHol groups did not exhibit a high percentage of residual milk as described for other zebu breeds [15] or for dairy cows submitted to different situations of stress [7,32] or during first milkings after parturition [6,16]. This confirms that CORT levels alone are often poor predictors of stress in lactating animals as reported by other research [33] and suggests that, if stress exists in Gir cows, it is not very acute and only concerns some animals in the group.…”

“…In other countries, some Bos indicus breeds are also susceptible to lactation failure [14,15] and retain high volumes of residual milk [15]. Disturbance of milk ejection can be attributed to a selective inhibition of OT release from the hypophysis gland as described after weaning [8,16]; in this case, normal milk ejection can be established after OT administration [6].…”

Effect of calf suckling on oxytocin, prolactin, growth hormone and milk yield in crossbred Gir $\times$ Holstein cows during milking

“…Similarly, other authors have observed that crossbred cows susceptible to lactation failure exhibit high residual milk, and have suggested that inhibition of OT release is a possible explanation for lactation failure [26]. This could explain why cows with poor milk yield depend on frequent udder stimulation, and in many cases present a failure of lactation when submitted to the classical management strategy of 2 exclusive milkings/day.…”

Oxytocin release and lactation performance in Syrian Shami cattle milked with and without suckling

“…In crossbred GyrrHolstein cows, Negrao & Marnet (2002) demonstrated similar OT release and similar milk yields in exclusively machine milked cows compared with a combined suckling and milking regime, whereas Murugaiyah et al (2001) reported reduced milk yields and increased apoptotic activity in exclusively machine milked crossbred SahiwalrHolstein cows. However, increased OT release and milk yields due to suckling even in highyielding Holstein cows that are adapted to machine milking demonstrate the crucial role of suckling in stimulating OT release (Bar-Peled et al 1995;Krohn, 2001).…”