Effect of Feeding Level Pre- and Post-Puberty and Body Weight at First Calving on Growth, Milk Production, and Fertility in Grazing Dairy Cows

Abstract

The effect of feeding to achieve differential growth rates in Holstein-Friesian (HF; n = 259) and Jersey (n = 430) heifers on time to puberty and first lactation milk production was investigated in a 3 x 2 factorial design. Holstein-Friesian and Jersey calves were reared to achieve a BW of 100 and 80 kg, respectively, at 100 d. At target weight, all calves were randomly allocated to one of 3 feeding treatments to achieve different growth rates. Holstein-Friesian and Jersey calves were fed fresh pasture to achieve average daily growth rates of 0.77, 0.53, or 0.37 kg of BW/d (HF) and 0.61, 0.48, or 0.30 kg of BW/d (Jersey), respectively. Period 1 (prepubertal) was imposed until HF and Jersey treatment groups averaged 200 and 165 kg of BW, respectively. Following period 1, HF and Jersey calves from each treatment group were randomly allocated to one of 2 feeding treatments to achieve average daily growth rates of 0.69 or 0.49 kg of BW/d (HF) and 0.58 and 0.43 kg of BW/d (Jersey), respectively. Period 2 (postpubertal) was imposed until 22 mo, when heifers were returned to their farms of origin. Body weight, body condition score, height, heart girth circumference (HGC), milk production, and fertility-related data were collected until the end of the third lactation. Time to reach puberty was negatively associated with level of feeding, and heifers attained puberty at the same BW (251 +/- 25.4 and 180 +/- 24.0 kg for HF and Jersey heifers, respectively). Heifers on high feed allowances during periods 1 and 2 were heavier, taller, and had greater HGC than their slower grown counterparts until 39 mo of age when height and HGC measurements stopped. Body weight differences remained until 51 mo, when measurements ceased. High feed allowance during period 1 (prepubertal) did not affect milk production during the first 2 lactations, but did reduce milk production in lactation 3. It is possible that the expected negative effect of accelerated pre-pubertal growth was masked by greater calving BW, as BW-corrected milk yield declined in both breeds with increasing prepubertal feed allowance. Growth rate during period 2 was positively correlated with first lactation milk production. Milk yield increased 7% in first lactation heifers on the high feed allowance, which resulted in higher growth rate during period 2. Milk production during subsequent lactations was not affected. Results suggest that accelerated prepubertal growth may reduce mammary development in grazing dairy cows, but this does not affect milk production in early lactations because of superior size. Body weight at calving and postpubertal growth rate management are important in first lactation milk production, but do not affect milk production in subsequent lactations.

Influence of age, body weight and body condition score before mating start date on the pubertal rate of maiden Holstein–Friesian heifers and implications for subsequent cow performance and profitability

“…These findings are in line with the studies of Gardner et al (1988), Abeni et al (2000) and Dobos et al (2001), who all showed a positive relationship between BW at first calving and subsequent milk production performance. In contrast, Macdonald et al (2005) found that BW at first calving is important for first lactation milk production, but its effect diminished in subsequent lactations. As reported by Carson et al (2002), heifers reared to calve at 620 kg lost more weight in early lactation and had a longer interval up to the first recorded oestrus than those reared to calve at 540 kg.…”

“…The importance of BW and BW gain is supported by the findings of many studies. Macdonald et al (2005) reported that attainment of puberty was influenced by BW gain in their study where BW gain was manipulated by varying feed allowances. This is in line with earlier studies by Arjie and Wiltbank (1971), Short and Bellows (1971) and Foldager et al (1988), whereby level of nutrition and average daily gain (ADG) were reported to significantly reduce the age at which animals reached puberty.…”

“…The negative effects of feeding intensity pre-puberty on milk yield potential because of mechanisms responsible for reduced mammary development have been widely documented (Le Cozler et al, 2008). However, this effect is less certain under grass-based systems (Macdonald et al, 2005), likely because of the less intensive nature of the rearing process. In the current study, only 4.8% of heifers gained more than 0.8 kg per day from birth (birth weight of 38 kg assumed; Olson et al, 2009), the threshold above which adverse consequences for milk production have been indicated (Zanton and Heinrichs, 2005).…”

Heifer fertility and carry over consequences for life time production in dairy and beef cattle

“…An investigation into the effects of different feeding regimes pre-and post-puberty on dairy heifers in New Zealand found no effects of a higher pre-pubertal feed intake on milk production in the first two lactations but those that survived made less milk in lactation 3. Macdonald et al (2005) suggested that the well-fed animals may have had decreased mammary development but compensated initially by an overall greater body size. Others have found that increasing ADG through increasing the plane of nutrition has a minimal impact on histological mammary development (Daniels et al, 2009).…”

“…Several groups have reported that a younger AFC in dairy heifers does not reduce, or may even increase, the first lactation yields, providing the animals are sufficiently well grown and the AFC is not less than 23 months (Ettema and Santos, 2004;Macdonald et al, 2005;Sakaguchi et al, 2005;Cooke et al, 2013). An AFC below 23 months is however generally detrimental with a large study by Eastham (2012) of UK dairy cows showing that heifers with an AFC < 23 months underperformed by producing less milk in each of lactations 1 to 4.…”