Association between dry period length and lactation performance, lactation curve, calf birth weight, and dystocia in Holstein dairy cows in Iran

Abstract

In this study, 65,971 lactations on 41,842 cows in 64 herds were used to determine the association between dry period length (DPL) and lactation performance, lactation curve, calf birth weight, and the incidence of calving difficulty during the subsequent parity in Holstein dairy cows in Iran. The length of the dry period was classified into 7 categories: 0 to 35d, 36 to 50d, 51 to 60d, 61 to 70d, 71 to 85d, 86 to 110d, and 111 to 160d. Cows with the standard DPL (51 to 60d) produced more 305-d milk, fat, and protein over the next lactation compared with those with shorter dry periods. Shorter dry periods (0 to 35d and 36 to 50d) were associated with lower initial milk yield, steeper inclining and declining slopes of the lactation curve, and higher milk persistency compared with dry period length of 51 to 60d. Peak lactation was achieved later in cows with 0- to 35-d and 36- to 50-d dry period length than in those with dry period length of 51 to 60d. We also observed a relationship between DPL and calf birth weight: smaller calf birth weight was recorded with a dry period of 51 to 60d compared with longer dry periods. The incidence of calving difficulty did not differ in cows with 51- to 60-d dry period compared with cows with 0- to 35-d and 36- to 50-d dry periods. In conclusion, the results of this study did not support previous findings that suggested a shorter dry period could be beneficial to dairy production.

Effects of dry period management and parity on rumen fermentation, blood metabolites, and liver triacylglyceride in dairy cows

“…Collier et al (2012) reported that the required length of dry period for the first parity cows is 60 d, while for the second parity and older cows it can be reduced to 30 d with no negative effect on production and health. On the other hand, Atashi et al (2013) showed that third parity and older cows need longer dry periods compared with younger animals. Khazanehei et al (2015) suggested that this difference between parity groups might be due to differences in growth and fat deposition between the first and second parity cows compared with the older cows.…”

Droogstand op maat : verkorten van de droogstand van melkvee: effecten op vervetting en persistentie, uiergezondheid, dierenwelzijn, melkproductie, economie en milieu

“…Ten eerste, zijn effecten van droogstandslengte op persistentie van de melkproductie in de volgende lactatie tot nu toe onduidelijk (Mantovani et al, 2010;Atashi et al, 2013;Chen et al, 2016a). Bovendien kan verondersteld worden dat aanpassingen in het rantsoen de persistentie van koeien met een verkorte of geen droogstand kunnen verbeteren.…”

Shortening or omitting the dry period in dairy cows : effects on milk yield, energy balance, metabolic status, and fertility

“…reported that omitting the DP resulted in an earlier time of peak yield (PT), lower PY, and lower LP in a small study (n = 17). On the contrary, Atashi et al (2013) found that a shortened DP (0 to 35 d) was associated with later PT, lower PY, and higher LP in a field study, compared with a conventional DP (50 to 60 d). In addition, both studies did not investigate effects of DP length on lactation curve characteristics in multiple lactations.…”

“…reported that omitting the DP resulted in an earlier PT, lower PY, and lower LP in a small study (n = 17) compared with a conventional DP. Atashi et al (2013) found that a shortened DP (0 to 35 d) was associated with later PT, lower PY, and higher LP in a field study compared with a conventional DP (50 to 60 d). The number of animals used in the study of was relatively low (n = 17) and the filed study of Atashi et al (2013) was not a preplanned experiment, which might bias the results.…”

“…Atashi et al (2013) found that a shortened DP (0 to 35 d) was associated with later PT, lower PY, and higher LP in a field study compared with a conventional DP (50 to 60 d). The number of animals used in the study of was relatively low (n = 17) and the filed study of Atashi et al (2013) was not a preplanned experiment, which might bias the results. Therefore, more studies are needed to verify whether the milk yield losses after shortening or omitting the DP is caused by decreased PY, or decreased LP, or both.…”