Dados do Trabalho

Título

A comparative study between Holstein, Jersey, and mixed herds under official milk-recording

Titulo em português

Um estudo comparativo entre rebanhos Holandês, Jersey e mistos sob controle leiteiro oficial

Introdução (obrigatório)

Brazil is the fourth largest milk producer in the world, and it produces more than 34 billion liters annually. Despite progress in the total milk produced, Brazil still has low zootechnical and productive indexes. The predominant genetic group chosen in different regions and distinct production systems has major impact on productive parameters. It is well established (LIM et al., 2020) that Holstein animals outperform Jersey cows in the volume of milk produced daily. On the other hand, Jersey animals outperform the Holstein breed when it comes to milk components contents. The goal of this study is to compare Holstein herds with Jersey or mixed herds enrolled in the milk recording program carried out by the Associação Paranaense de Criadores de Bovinos da Raça Holandesa (APCBRH), which is the most important DHI (Dairy Herd Improvement) organization in Brazil, with almost 70% of all Brazilian official milk-recorded cows.

Material e métodos (obrigatório)

The present study compiled data from herds enrolled in the DHI service, from July 2023 to April 2024, from 247 dairy herds in the Campos Gerais region of Paraná State. From these 247 herds, 99 were categorized as large and more technologically advanced herds and 148 were categorized as small and medium-sized herds. Concerning the predominantly breed, 158 were Holstein herds, 61 Jersey herds, and 28 mixed and crossbred herds. The predominant breed was considered when the herd had 80% or more animals of the same breed; below 80%, they were considered mixed or crossbred herds. A total of 1,662 monthly reports were analyzed; 1,145 from Holstein herds (68.9%), 335 from Jersey herds (20.2%), and 182 mixed or crossbred herds (10.9%). Within the DHI monthly reports, ten indexes were measured: average daily milk production, milk production corrected for 180 days in milk (DIM), DIM itself, milk fat %, milk protein %, milk lactose %, milk total solids %, somatic cell count (SCC), cows’ average age, and days open. SAS software version 9.4 (SAS Institute Inc., Cary, NC) was used for data editing and analysis. The effects of breed (Holstein, Jersey or mixed and crossbred) and herd’s category (small/medium or large herds) were considered as fixed effects, and herd ID was included as a random effect. Data editing was carried out using MEANS and FREQ procedures of SAS, while associations of fixed and random effects were obtained using the MIXED procedure. A significance level of 5% was used in all tests.

Resultados e discussão (obrigatório)

Daily milk production and 180-DIM corrected milk production Predominantly Holstein herds had higher (P<0.01) daily milk averages than predominantly Jersey and mixed herds (29.27, 22.97, and 24.41 kg/d, respectively). Milk production corrected for 180 DIM was also higher (P<0.01) on predominantly Holstein herds when compared with Jersey and mixed herds (31.15, 24.63, and 26.74 kg/d). The breed factor has a great influence on the herd productivity, and it is already well established that Holstein cows have higher daily milk production than Jersey ones. Days in milk The variable days in milk did not differ (P=0.28) among Holstein, Jersey or mixed herds: 202.5, 200.4, 204.1 d, respectively, showing no breed effect on DIM.  Milk fat, protein, and total solids contents Milk composition differences (P<0.01) were found comparing Holstein, Jersey and mixed herds for milk fat content (3.64, 4.35, and 3.43%), milk protein content (3.25, 3.56, and 3.43%) and milk total solids content (12.46, 13.37, and 12.84%). While Holstein cows are superior in daily milk production, Jersey animals have significantly higher percentages of milk fat, protein and total solids. Milk components are important factors which have a direct effect on the quality and yield of dairy products. Another factor to be considered is that dairy farmers in this region receive bonus for higher milk fat and protein contents by the milk payment system adopted by Pool Leite (an integrated system of the three main cooperatives in the region). Milk lactose and somatic cell count Predominantly Holstein herds showed higher (P<0.01) lactose content than Jersey or mixed herds (4.59, 4.48, and 4.52%, respectively). Somatic cell count also differ (P=0.03) among herds with distinct genetic groups; Jersey herds showed lower SCC values when compared to Holstein or mixed herds (263, 329, and 362 cellsx103/mL; respectively). Mainly somatic cell count, but also milk lactose content, were indicators of mammary gland health and microbiological milk quality. Previous studies (LIM et al., 2020) showed that Jersey herds had a lower SCC when compared to Holsteins, corroborating the results found in the present study.  Cows’ average age Jersey breed herds showed greater (P<0.01) longevity when compared to Holstein or mixed herds (60.5, 51.9, and 54.5 months, respectively). It has been shown in previous studies (LIM et al., 2020) that the Jersey breed has a longer productive life when compared to the Holstein breed, corroborating our results. Days open No differences (P=0.46) were found for days open among Holstein, Jersey and mixed herds (151.1, 159.5, and 147.3 d, respectively), suggesting that all three genetic groups have the potential to improve their reproductive indexes.  Our results are, for the most part, in accordance with results previously found in the literature. However, as far our knowledge goes, there are no previous studies which compared official milk-recorded Holstein, Jersey and mixed herds including almost all herds in the same region, since this study is the first one to encourage the practice of official DHI on all dairy herds associated with dairy cooperatives.

Conclusão (obrigatório)

Holstein herds showed higher daily milk production, however, Jersey herds produce milk with higher milk solids, mainly fat and protein. The decision to choose one of these two breeds is dependable of the producer’s preference but maybe even more important, the adoption of a milk payment system based on milk quality and composition.

Referências bibliográficas (opcional)

LIM, D.H., V. MAYAKRISHNAN, H.J. LEE, K.S. KI, T.I. KIM, & Y. KIM. A comparative study on milk composition of Jersey and Holstein dairy cows during the early lactation. Journal of Animal Science and Technology, 62(4), 565-576, 2020.