Energy requirements of gestating dairy cows

Energy requirements of gestating dairy cows

In dairy cows, the later stages of gestation play a pivotal role in priming the mammary gland for upcoming lactation and facilitating fetal development [1]. Nonetheless, there exists a scarcity of research focused on quantifying energy needs throughout the gestation period [1, 2, 3, 4]. Within the range of existing requirement frameworks [5, 6, 7, 8], the NRC [6] is extensively employed in the context of dairy cattle.

The NRC [6] determined the energy prerequisites for gestation based on findings by Bell et al. [3], while Ferrell et al. [1] evaluated the efficiency of metabolizable energy utilization by the embryo. Bell et al. [3] proposed that the energy demand for gestation gains significance after 190 days, exhibiting a linear rise up to 279 days. These requirements for gestation were obtained using Bos taurus breeds.

Therefore, when evaluating the needs of animals from different breeds, such as the crossbreed of Bos taurus × Bos indicus (Holstein × Gyr), there is no concrete evidence that energy demands for gestation are the same.

The Brazilian dairy industry is composed of approximately 70% Holstein × Gyr animals [9, 10], and this crossbreed exhibits higher milk production than the Gyr breed itself.

energy-gestating dairy cows This increased milk production is likely the result of heterosis, which incorporates the best characteristics of each breed: Holstein’s milk production capability and Gyr’s adaptability to tropical climates [10].

In a meta-analysis, Oliveira [11] found lower maintenance requirements and lower efficiency for milk production in Bos taurus × Bos indicus breeds compared to Bos taurus breeds. However, as far as we know, there is no quantitative data available regarding the nutrient requirements of Holstein × Gyr cows during gestation. Additionally, no studies have been found concerning weight gain requirements for Holstein × Gyr cows.

Estimation of energy requirements for gestating cows

The objective of this study was to estimate the energy requirements of Holstein × Gyr cows during gestation. Different feeding patterns were established using two administration protocols: ad libitum or maintenance. Sixty-two non-lactating cows with an average body weight of 480 ± 10.1 kg and an age of 5 ± 0.5 years were used. The cows were divided into three groups: pregnant (n = 44), non-pregnant (n = 12), and reference (n = 6). The 56 pregnant and non-pregnant cows were randomly assigned to a feeding regimen: ad libitum or maintenance.

In order to assess the impacts of various gestational periods, both pregnant and non-pregnant animals were slaughtered at intervals of 140, 200, 240, and 270 days following the onset of gestation.

The energy requirements for maintenance exhibited differences between pregnant and non-pregnant cows, thereby giving rise to the formulation of two distinct equations.

The net energy and metabolizable energy requirements for maintenance of non-pregnant cows were 82 kcal/kg of fasting body weight 0.75/day and 132 kcal/kg of fasting body weight 0.75/day, respectively.

The efficiency of metabolizable energy utilization for maintenance of non-pregnant cows was 62.4%.

The net energy and metabolizable energy requirements for maintenance of gestating cows were 86 kcal/kg of fasting body weight 0.75/day and 137 kcal/kg of fasting body weight 0.75/day, respectively.

The efficiency of metabolizable energy utilization for maintenance of gestating cows was 62.5%.

The efficiency of metabolizable energy utilization for weight gain was 41.9%.

The efficiency of metabolizable energy utilization for gestation was 14.1%.

Furthermore, the net energy requirement for gestation deviated from zero, commencing on the 70th day of the gestational period.

In summary, the net energy and metabolizable energy requirements for maintenance vary between pregnant and non-pregnant cows. Furthermore, researchers from the aforementioned study consider that the proposed nonlinear equations for estimating net energy requirements for gestation are more suitable than the current NRC equation and should be recommended for Holstein × Gyr cows.

Source: Journal Plos One

You may also like to read: “Dairy Cattle Nutrition during the Transition Period.”

Bibliographical References:

1. Ferrell CL, Garrett WN, Hinman N, Grichting G. Energy utilization by pregnant and non-pregnant heifers. J Anim Sci. 1976;42: 937–950. pmid:1262293
2. Moe PW, Tyrrell HF. Metabolizable energy requirements of pregnant dairy cows. J Dairy Sci. 1972;55: 480–483. pmid:5063018
3. Bell AW, Slepetis R, Ehrhardt UA. Growth and accretion of energy and protein in the gravid uterus during late pregnancy in Holstein cows. J Dairy Sci. 1995;78: 1954–1961. pmid:8550905
4. BR-CORTE. ‘Nutrient requirements of Zebu and crossbred.’ (3rd ed). (Suprema Gráfica e Editora: Visconde do Rio Branco. MG, Brazil); 2016.
5. AFRC ‘Energy and protein requirements of ruminants.’ (1st ed). (CAB International: Wallingford, UK); 1993.
6. NRC ‘Nutrient requirements of dairy cattle (7th ed).’ (National Academic. Press: Washington DC); 2001.
7. CSIRO; `Nutrient requirements of domesticated ruminants.’ (Australia Agricultural Council: Victoria); 1965.
8. INRA. ‘Alimentation des bovins, ovins et caprins. Besoins des animaux. Valeurs des aliments.’ (Agabriel J., ed. Editions Quae, Versailles, France); 2007.
9. Ruas JRM, Menezes AC, Queiroz DS, Silva EA da, Costa MD da. Cruzamentos para a produção sustentável de leite. EMBRAPA—Pesquisa, desenvolvimento e inovação para a sustentabilidade da bovinocultura leiteira. 10th ed. 2011: 189–190.
10. Carvalho PHA, Borges ALCC, Silva RR, Lage HF, Vivenza PAD, Ruas JRM, et al. Energy metabolism and partition of lactating Zebu and crossbred Zebu cows in different planes of nutrition. Loor JJ, editor. PLoS One. 2018;13: 1–10. pmid:30118491
11. Oliveira AS. Meta-analysis of feeding trials to estimate energy requirements of dairy cows under tropical condition. Anim Feed Sci Technol. 2015;210: 94–103.