A survey of calf rearing practices in the south-west region of Western Australia

ABSTRACT

Aims

To gather data on the calf management and rearing practices of a subset of dairy farmers in the south-west region of Western Australia.

Methods

A 30-minute face-to-face survey was conducted with dairy cattle producers in the south-west region of Western Australia from April–June 2019 to determine pre-weaning calf rearing practices. Participation was voluntary, using a self-selected subset of dairy farmers registered with a regional extension group. The questionnaire assessed three broad categories: farm demographics, colostrum harvesting and management and calf rearing practices.

Results

The study response rate was 34/140 (24%). The following key areas were identified where there were deviations from recognised best practice: Precalving: no transition diet was fed pre-calving on 4/34 (12%) of farms, and on a further 5/34 (15%) it was fed for less than 3 weeks; mixing of heifers and adult cows in the calving paddocks occurred in 24/34 (70%) of the farms, with 15% (5/34) of the farms using calving induction. During calving 14/34 (41%) of the farms did not disinfect navels of new-born calves; although 23/34 farmers stated that they collected calves within 6 hours of birth, data on frequency of calf pick-up (2/34 did not separate calves and dams and 19/34 picked up only once per day) indicated that on 21/34 farms (62%) the reality was that calves were picked up >12 hours after birth. Colostrum quality was not assessed appropriately on 18/34 (53%) farms and farmers overestimated how soon after birth it was administered: 23/34 (68%) reported feeding it within 6 hours of calving, despite 62% picking up calves >12 hours after calving. Regarding calf rearing practices, no pain relief before or after dehorning was used on 20/34 (59%) farms, calf bedding was removed infrequently (<weekly) on 26/35 (76%) farms and appropriate isolation of sick calves was only reported by 14/34 (41%) farmers.

Conclusion and clinical relevance

Although limited by the low response rate, this is the first survey of dairy calf rearing practices in the south-western region of Western Australia. We found evidence of at least one process inconsistent with industry best-practice on 34/140 (24%) of responding farms and all farms had more than one sub-optimal calf rearing practice. This highlights the need to improve calf rearing in this region and identifies key areas of deficiency for further study and extension to producers.

KEYWORDS:

• Calf
• health
• management
• rearing
• welfare

Introduction

Constant evaluation and improvement of farming practices supports and promotes better animal health and welfare outcomes (Beggs 2018; Urie et al. 2018). Rearing healthier, more robust replacement heifers leads to better immunity, lifetime growth, reproductive efficiency and milk production, compared with less healthy heifers (Stanton et al. 2012; Chuck 2016; Chuck et al. 2018). The rearing of replacement heifers is also more profitable than purchasing replacement heifers (Wells et al. 1997; Swali and Wathes 2006). Guidance on best practice in animal care is available to producers based on farming policies and legislation, evidence-based veterinary medicine, scientific reports and farming guidelines such as the Australian Animal Welfare Standards and Guidelines for Cattle (Dairy Australia 2011; Animal Health Australia 2014).

Dairying in Western Australia is unique due to the Mediterranean climate and the presence of larger dairies (mean 54 (min 47, max 1,821) ha) compared with other states (mean 23 (min 21, max 647) ha) in Australia (Aleri and Laurence 2020). However, there is a lack of information on the range of calf animal health and welfare practices adopted in Western Australian dairies. As part of the dairy cattle medicine, health and welfare surveillance programme at Murdoch University (Perth, Western Australia), we conducted a cross-sectional farm survey with the objective to determine the calf management and rearing practices of a sub-set of dairy farmers in the south-west region of Western Australia.

Materials and methods

Ethics approval

The study was conducted in accordance with the Australian Code of Practice for the Care and Use of Animals for Scientific Purposes, with the approval of the Human Research and Animal Ethics Committees of Murdoch University, Approval Nos. R3144/19 and 2019/047 respectively.

Study area, design and general data collection

The study was conducted in the south-west region of Western Australia. The region has a temperate Mediterranean climate with a mean annual rainfall of approximately 730 mm (DAFWA 2016). To identify calf management practices potentially associated with calf health and welfare, a cross-sectional on-farm survey using face-to-face interviews with farm owners/managers was conducted by one author (JWA), using a standard questionnaire (Supplementary Material I), from April to June 2019.

Study populations and selection of study farms

The target and source populations were 140 dairy farms registered with Western Dairy (a regional extension group in the south-west region of Western Australia). Invitations to the study participants were sent via email to all 140 farms via a regional newsletter (Feed Trough) and during a day event for the region's farmers. Participation was voluntary, and no incentives were provided.

Sample size estimations

The following assumptions were made for the purposes of a sample size calculation: that if the true proportion of farms with optimal calf rearing practices is 20%, and the survey was 100% sensitive and specific in identifying optimal practice, with a sample size of 44, 95% of the time, the true proportion will be within an interval of ±10% of our estimated proportion (Sergeant 2018). With a 10% inclusion for non-response rate and missing data, a total of 50 farms was targeted.

Questionnaire design

A three-stage process was used to develop and select questions for the final questionnaire. First >100 questions on calf health and welfare assessment drawn from published data (Vasseur et al. 2010; Phipps 2016), were pooled, prioritising those relating to calf management and rearing practices. These were then trialled with five farmers. To allow the questionnaire to be completed within 30 minutes, 30 questions were removed based on relevance to calf health and welfare. The survey covered 11 broad categories with 76 questions: 17 on general farm information, 33 on colostrum harvesting and management and 26 on calf rearing.

Epidemiological parameters

The individual farm was the unit of concern, and the various calf management and rearing practices associated with the health and welfare of dairy calves (Vasseur et al. 2010; Phipps 2016) were collated. Questionnaire responses were recorded as binary (yes/no), nominal and/or continuous variables.

Data handling and analysis

Responses were entered into an Excel (Microsoft Corp, Redmond, WA, USA) spreadsheet, checked twice for any errors and deidentified to maintain the confidentiality of the participants. Data were analysed using SSPS software version 22.0 (2013 SPSS; Chicago, IL, USA). Appropriate parametric and non-parametric descriptive statistics (measure of central tendency and precision) were generated for all data.

Results

Response rate

The study recorded a response rate of 24.3% (34/140).

General farm descriptions

A summary of the general herd characteristics is presented in Supplementary Material II, Table 2. The median farm size was 324 (min 40, max 2,226) ha. The most prevalent breeds were pure Holstein-Friesians and their crosses, reared in 20/34 (60%) of the farms. The median herd milk production/cow/year was 8,500 (min 2,300, max 10,000) L. Calving patterns included year-round, seasonal and split-calving, practised by 16/34 (47%), 16/34 (47%) and 2/34 (6%) of the farms, respectively. The median replacement number of heifers/year was 80 (min 20, max 100). The median grain supplementation rate was 2.5 (min 0, max 11) tonnes/cow/year. Irrigation was used on 19/34 (54%) farms. The median number of milking personnel was two and most farms milked the cows twice daily. Sick animals were identified by marking animals (paint) and recording cow identity in 30/34 (88%) farms, marking animals only in 2/34 (6%) farms and recording identity only in 2/34 (6%) farms.

Peri-calving management

A detailed description of peri-calving management practices is presented in Supplementary Material II, Tables 3 and 4.

Pre-calving practices to improve colostrum quality

Dams were vaccinated prior to calving on 23/34 (68%) farms. A total of 19/34 (56%) farms vaccinated cows against clostridial disease and leptospirosis and 4/34 (12%) vaccinated against these diseases and BVD. Although 30/34 (88%) farms reported feeding a transition diet to cows pre-calving, 9/34 (26%) farms reported feeding no transition diet or feeding one for ≤3 weeks.

Calving management

On the majority of farms (30/34; 88%), calving occurred in designated “calving paddocks” in close proximity to the milking plant with 4/34 (12%) farms using a permanent shed as the calving area. Mixing of heifers with adult cows in the calving paddocks was practiced in 24/34 (70%) farms. Calving induction was only practiced in 5/34 (15%) farms.

Care of the new born calf and calf-dam separation

The median number of personnel responsible for observing calving was two (min one, max five). Approximately half of the farms (18/34; 53%) disinfected the navel of calves. Most of the farms (29/34; 85%) did not identify calves by ear-tagging in their first day of life. A minority of farms collected calves twice or more during the day (11/34; 32%) with the balance collecting once daily, not at all or failing to specify. The collection of calves on most farms (29/34; 85%) was assigned to more than two staff members.

Colostrum management

The sources of colostrum as observed from this study are detailed in Supplementary Material II, Table 4. A majority of the farms (27/34; 79.4%) included fresh colostrum from the dams but 18/34 (53%) pooled colostrum in differing ways. There was conflicting information reported about the time between calving and the first feed of colostrum. Whilst 23/34 (68%) farmers stated that they removed calves from their dam and fed colostrum within 6 hours of calving 21/34 also reported that calves were either not separated or only collected once per day. As calving may occur at any point within the 24 hours of the day, to feed colostrum within 6 hours of birth requires that calves are picked up at least 4 times per day. There was variability in the feeding of colostrum with 19/34 (56%) farms allowing both direct nursing and assisted feeding by bottle feeding. There was a similar level of ambiguity in the responses to the volume of colostrum fed. Whilst 25/34 (74%) farmers reported feeding up to a maximum of 2 L of colostrum per calf, and the remainder 3 L per calf, 6/34 (18%) also reported relying on suckling alone for colostrum intake, making volume assessment unreliable for these calves. Most farms (21/34; 62%) fed colostrum for >1 day and pooling of colostrum was common (18/34, 53%). Frozen colostrum was stored for a mean of 3.3 months and up to 12 months, but no producers used preservatives to preserve colostrum. A small proportion of farms (5/34; 14.5%) did not store colostrum. Colostrum from first calvers was utilised by 17/34 (50%) farms. Appropriate assessment of colostrum quality prior to the feeding of calves was conducted in 15/34 (44%) farms using a Brix refractometer, with one farm using a colostrometer. On the remaining farms, colostrum quality was either not measured or estimated visually. No producers measured the transfer of passive immunity in the calves.

Calf rearing

A detailed description of calf rearing practices as observed in this study is shown in Supplementary Material II, Tables 5, 6 and 7.

Calf feeding practices

Milk feeding practices are detailed in Supplementary Material II, Table 5. Farmers estimated that the milk volume fed to calves was 2 L twice a day although this was not formally measured or recorded. Feeding method varied widely between farms but group feeding systems (calfeteria and/or teat bucket systems) where individual intake is uncontrolled and cross suckling possible, predominated and all producers fed pooled raw milk to the calves. The introduction of calf pellets was delayed beyond the first week on 19/34 (56%) of farms, with most farms allowing ad libitum access to water but on 14/32 (46%) drinking water was only provided at specific times of the day.

Calf housing type

The most common housing systems were permanent purpose-designed calf sheds on 23/34 (68%) farms. Some form of loose bedding material was provided on 25/34 (74%) farms with the remainder using mats, grating, earth, concrete or unspecified. For most of the pre-weaning period, most farms (30/34; 88%) kept calves in groups of 5–10, but on 17/34 (50%) farms, calves were kept individually for the first few days before mixing. A detailed description of the frequency of cleaning bedding is given in Supplementary Material II, Table 6. Only 9/34 (26%) farms reported cleaning the bedding at least weekly with 15/34 (44%) farms only cleaning it at the end of the weaning period.

Disease prevention

Vaccination was reported on 28/34 (82%) farms. The median age at which the primary and secondary vaccinations were administered to the calves was 8 (min 4, max 12) weeks and 12 (min 12, max 55) weeks respectively.

Dehorning and management of painful procedures

Dehorning (disbudding) was done at a median age of 5.5 (min 1, max 77) weeks and on 26/34 (76%) farms, by farm personnel. Most of the farms (20/34; 59%) did not use local anaesthetic prior to dehorning, nor non-steroidal anti-inflammatory drugs for post-operative analgesia.

Weaning protocols

A detailed description of the weaning protocols used by all farms is provided in Supplementary Material II, Table 7. The median age at weaning was 12 (min 6, max 20) weeks. The most common weaning method reported was based on a combination of age and weight (11/34; 32%) followed by weaning on age only (10/34; 29%), weaning based on weight only (8/34; 24%) and weaning based on concentrate consumption only. There was inconsistency in the recording of weaning weight and feed intake by the producers.

Managing sick calves

A total of 31/34 (91%) producers had treatment protocols for treating any sick calves before seeking a veterinarian’s advice. The practice of isolating sick calves from the healthy group of calves until recovery was routinely practiced by only 14/34 (41%) farms, as summarised in Supplementary Material II, Table 7.

Personnel responsible for rearing calves

A summary of the personnel responsible for rearing calves is shown in Supplementary Material II, Table 7.

Discussion

This study quantifies some of the pre-weaning calf rearing practices in the south-west pasture-based dairy production system of Western Australia.

The practice of vaccinating pregnant dams prior to calving was recorded on most farms. However, only 17% of the farms fed a transition diet at least 5 weeks prior to calving. These practices are not only important for the synthesis of high-quality colostrum (Quigley and Drewry 1998; Weaver et al. 2000; Denholm et al. 2017) and reducing metabolic and infectious diseases (Goff and Horst 1997; Aleri et al. 2016), but also support optimal dam health and welfare. The practice of calving induction was conducted on a small proportion of the farms. The Australian dairy industry discourages this practice and has made a commitment to phase it out by 1 January 2022 (Dairy Australia 2019). In New Zealand, calving induction is not practiced (ADIC 2020). Calving induction has the potential to interfere with the normal physiological transfer of immunoglobulins and may be considered fundamentally unethical (Refsdal 2000; Borman et al. 2004). This study suggests there is a need to continue educating farmers on the disadvantages of calving induction.

The paddock calving system observed from this study is a common practice in pasture-based dairy production systems in Australia (Dairy Australia 2011, 2017, 2019) and New Zealand (Neave et al. 2022), contrary to the use of calving pens and tie stalls seen in North America (Vasseur et al. 2010; Urie et al. 2018). Whilst the implications of these practices have not been fully elucidated, optimal management practices such as the number of times new-born calves are drafted, fresh cow milking policy, colostrum harvesting, storage and feeding policy, navel disinfection and timely tagging, can ameliorate some of their potential disadvantages such as failure of passive transfer of immunity. In the current study, there were deficiencies in these management practices similar to those recorded in New Zealand research (Denholm et al. 2017). There is benefit in educating farmers on the impact of these practices. In a recent study within Western Australia, the prevalence of failure of passive transfer in newborn dairy calves was demonstrated to be low (Aleri et al. 2021). In the present study, the practice of infrequent calving surveillance or the late removal of calves from their dams allowed calves to nurse their mothers more, but precluded the estimation of the actual volume of colostrum ingested by calves in the initial hours after birth. Whilst these observations are similar to the findings from other studies (Kehoe et al. 2007; Vasseur et al. 2010), it has also been shown that calves receiving colostrum mostly by self-nursing are at greater risk of failure of passive transfer of immunity (Franklin et al. 2003).

From the current study, the assessment of colostrum quality prior to the feeding of calves was conducted on less than half of the farms. This finding is in agreement with the findings of other studies in Australia where colostrum quality was occasionally assessed, but contrary to observations from Canada where colostrum quality was generally not assessed (Vasseur et al. 2010). Estimation of colostrum quality allows producers to select high-quality colostrum for the first feed and alerts them to any systematic quality issues. There is a need to emphasise the importance of accurate estimation of colostrum concentration to ensure high-quality colostrum is fed to the calves. Proper handling and storage of colostrum maintains quality. Studies have previously demonstrated that poor colostrum management is associated with a high incidence of diseases such as calf diarrhoea (Svensson et al. 2006). Pooling of colostrum was practiced on most farms. The practice of pooling colostrum has the potential to increase contamination of colostrum, possibly increasing calves’ exposure to pathogens (Weaver et al. 2000). Most farms included fresh colostrum from the dams and no producers fed pasteurised colostrum. There is a potential risk in spreading a number of diseases such as Mycoplasma bovis when utilising pooled unpasteurised colostrum and milk (Parkinson et al. 2019).

The findings of this study showed that group feeding systems were the most frequently used method for milk. Estimations of the actual volume of milk consumed by calves were beyond the scope of this study. A possible management strategy to ensure milk is consumed without competition is to avoid overcrowding and group calves based on age or size. Adequate volumes of milk have been associated with benefits such as increased growth rate, and better reproductive and production performance of the replacement heifers in their first and second lactations (Khan et al. 2007; Chuck et al. 2018). From this study, a majority of the farms housed calves in groups of five to ten. These findings align with recent reports in Australia’s eastern states (Phipps 2016). Group housing has the potential to foster better social interactions among calves but poses a higher risk of the spread of infectious diseases. In this study, isolation of sick calves from the healthy group of calves was routinely practiced on a minority of farms. There is a need to continue emphasising the importance of this disease management strategy along with others such as disinfection and quarantine (Aleri and Laurence 2020).

Dehorning is a painful procedure performed in calves and raises significant animal welfare and public concerns (Stafford and Mellor 2005; Huxley and Whay 2006; Hewson et al. 2007). From this study, it was observed that dehorning was commonly performed by the farm personnel without the use of pain relief pre- and post-dehorning. The use of anaesthesia for disbudding is not compulsory in Australia, in contrast to other countries such as New Zealand and Canada (NFACC 2008; Animal Health Australia 2014), however, there is increasing consensus that appropriate pain relief strategies are required.

The findings of this study revealed that all producers had treatment protocols for treating sick calves prior to seeking a veterinarian’s advice. This is an important calf welfare practice that shows preparedness and awareness among the producers. A follow-up question on the type and specifications of the various treatment protocols was beyond the scope of this study.

This study found that a combination of age and estimated weight were the common weaning criteria used. Less than 10% of the producers weaned calves concentrate consumption. It has been recommended that the best weaning indicator in Holstein-Friesian calves is based on the consumption of 1.5–2.0 kg/day of concentrate when on a diet containing 17–18% crude protein (Dairy Australia 2017). Increased concentrate consumption supports papillae growth within the rumen for increased surface area for the absorption of volatile fatty acids (Baldwin et al. 2004). Not all farms recorded weaning weight and feed intake during the weaning period. These observations are similar to studies in other regions in Australia (Chuck 2016; Chuck et al. 2018). Optimum management of weaning avoids the “post-weaning slump” (decrease in body weight post-weaning) and promotes better reproductive and production performance (Chuck 2016). Measuring weaning weights and concentrates fed was beyond the scope of the study. There is a need for continued education on good transition weaning and its consequences for early life reproductive performance (Chuck 2016; Chuck et al. 2018).

A limitation of the survey design is that we could not be certain that all farmers received and read the email invitation and newsletter announcement. Another limitation to the study was the low response rate of approximately 25%, despite aiming for 33%. However, these results provide information on pre-weaned dairy calf rearing practices in the south-west region of Western Australia.

We identified good practices in calf management, but also some welfare and health risk factors. These were (1) delayed feeding of transition diet, (2) mixing of heifers and adult cows in the calving paddocks, (3) lack of navel disinfection, (4) delayed collection of newborn calves in the calving paddocks (5) failure to determine colostrum quality, (6) conducting dehorning without pain relief, (7) the infrequent removal of straw beddings and, (8) poor weaning protocols. This management survey contributes to understanding the practices that should be focussed on in intervention strategies and highlights the need to educate producers on these areas.

Acknowledgements

We thank Drs Kathryn Davis, Jo Coombe, Stephanie Bullen and John Penry (Dairy Australia) for their support for this study. We acknowledge the support of Western Dairy (Esther Jones and Jessica Andony) towards facilitating this study. We thank John Abbot and Aprille Jack for their technical assistance and the many producers for their kind participation in this study. The study was supported by a grant from Dairy Australia [grant number 16085] and partly by Murdoch University [grant number 13363].